Process for producing plasma polymerized film

A process for producing a plasma polymerized film, which comprises forming a plasma polymerized film on the surface of a substrate placed in a reaction zone by subjecting an organic compound containing gas to plasma polymerization utilizing low temperature plasma formed by pulse discharging, in which the time for non-discharge condition is at least 1 msec. and the voltage rise time for gas breakdown is not longer than 100 msec. The plasma polymerized film obtained has a small coefficient of friction, high lubricity, durability and heat resistance and is useful as a solid lubricating film, etc.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a process for producing a plasma polymerized film 
by utilizing low temperature plasma, particularly to a process for 
producing a plasma polymerized film by pulse discharging. 
2. Description of the Prior Art 
In use, magnetic tapes, magnetic discs, and the like are placed in a 
sliding relationship with structural elements, mechanical members, and the 
like, and the surfaces in sliding contact require lubricity with a small 
coefficient of friction. 
One of the methods known in the art for improving the lubricity of such a 
sliding surface is to coat the sliding surface with an organic lubricant 
comprising a fatty acid, and it has been utilized for magnetic tapes, 
magnetic discs, etc. However, this method has drawbacks in that the 
lubricant cannot easily be applied uniformly on the sliding surface, the 
effect may differ depending on the material of the surface to be coated 
and therefore no satisfactory lubricity can necessarily be obtained, the 
durability of lubricity is poor because the lubricant is lost gradually by 
repeated use, and that it has no heat resistance and therefore cannot be 
used at high temperatures. In addition, it is not applicable for precision 
machines such as watches and robots. Another method for improvement of 
lubricity is the method in which the sliding surface is coated with 
inorganic powder such as graphite powder, molybdenum sulfide powder, lead 
oxide, calcium fluoride, etc. This method has been utilized for mechanical 
elements such as gears, bearings, etc. However, this method also involves 
the same drawbacks as the above organic lubricant. Still another method 
known in the art is to form a solid lubricating film composed of, for 
example, polytetrafluoroethylene on the sliding surface and it has been 
used for sliding surfaces for which chemical resistance is required and 
sliding surfaces for which heat resistance is required. However, since the 
lubricating film which can be formed is considerably thick on the order of 
several tens microns or more, it has the drawback of being not applicable 
for the bearings, gears, and other such parts of precision machines, video 
heads, magnetic tapes, magnetic discs and others. 
SUMMARY OF THE INVENTION 
Accordingly, an object of the present invention is to provide a process for 
producing a plasma polymerized film having low coefficient of friction, 
excellent lubricity even with a very thin film, and good durability and 
heat resistance. 
The present invention provides a process for producing a plasma polymerized 
film, which comprises forming a plasma polymerized film on the surface of 
a substrate placed in a reaction zone by subjecting an organic compound 
containing gas to plasma polymerization utilizing low temperature plasma 
formed by pulse discharging, in which the time of non-discharge condition 
is at least 1 msec. and the voltage rise time for gas breakdown is not 
longer than 100 msec. 
Low temperature plasma, which as used herein is a term used in contrast to 
high temperature plasma, means a plasma in which the electron temperature 
is tens of thousands K. but neutral gas temperature and ion temperature 
are 2,000 K. or lower. Specifically it is a plasma stable at a plasma 
system pressure of 10 Torr or lower, generally from 0.1 mTorr to 10 Torr. 
The plasma polymerized film obtained according to the process of the 
present invention, when employing the same organic compound as the 
monomer, is considerably smaller in coefficient of friction as compared 
with the plasma polymerized film obtained according to the continuous 
plasma polymerization method of the prior art, and it is also possible to 
make the coefficient of friction markedly smaller by appropriate selection 
of the organic compound which is the monomer. 
Also, the above plasma polymerized film can be made excellent with respect 
to acid resistance, alkali resistance, solvent resistance, etc., by 
appropriate selection of the organic compound which is the monomer, and 
therefore, when these characteristics are required in combination with 
lubricity, or even when these characteristics are required without 
lubricity, it is useful as the surface protective film, etc. 
Further, as the general characteristics of the plasma polymerized film 
obtained by the present invention, it has partially the structural 
features and the physical or chemical characteristics of the organic 
compound which is the monomer. For example, plasma polymerized film 
obtained when using an organic compound having amino group as the monomer 
will be a polymer having a large number of amino group and with excellent 
biocompatibility. Plasma polymerized film having biocompatibility in 
addition to the various characteristics described above is useful as a 
coating material for artificial organs, artificial blood vessels, 
artificial joints, artificial skin, and the like.

DETAILED DESCRIPTION OF THE INVENTION 
If pulse voltage is periodically applied to a gas, when the voltage for 
each pulse surpasses the gas breakdown voltage, gas breakdown will occur, 
initiating discharging, and discharging will stop when the applied voltage 
goes below a certain level. This is repeated periodically. In this 
specification, "pulse discharging" means discharging which is caused to 
occur periodically by the pulse voltage applied periodically to a gas. By 
"time of discharge condition in pulse discharging" is meant the time from 
the initiation of discharging by gas breakdown to the stopping of the 
discharging in one cycle of pulse discharging. By "time of non-discharge 
condition in pulse discharging" is meant the time from the stopping of the 
discharging to the subsequent initiation of discharging by gas breakdown 
in one cycle of pulse discharging. By "voltage rise time for gas 
breakdown" is meant the time from the time when the applied voltage is 0 V 
or one tenth as great as the voltage at the time of the discharge 
condition to the time when it surpasses the gas breakdown voltage. The 
voltage rise time for gas breakdown corresponds to the final portion of 
the time of non-discharge condition in the pulse discharging, and it is 
the time of transition from the non-discharge condition to the discharge 
conditions. Referring now to the illustration shown in FIG. 1, this figure 
shows an example of the wave form of the voltage when a direct current 
pulse voltage is applied to a gas to generate pulse discharging. In this 
figure, .tau..sub.on indicates the time of discharge condition in pulse 
discharging, .tau..sub.off indicates the time of non-discharge condition 
in pulse discharging, and .tau. indicates the voltage rise time for gas 
breakdown. 
The time of the discharge condition, the time of the non-discharge 
condition and the voltage rise time for gas breakdown in a given pulse 
discharging can be measured by a commercially available wave form 
measuring instrument such as an oscilloscope, synchroscope, digital 
synchroscope, storage oscilloscope, digital storage oscilloscope and the 
like. The time of the discharge condition and the time of the 
non-discharge condition in pulse discharging can be controlled by 
connecting a commercially available function generator to a power 
amplifier and changing the form of the function. The voltage rise time for 
gas breakdown can be controlled by regulation of the voltage rise time and 
the set voltage in the pulse generator in the case of direct current 
discharge, while it can be controlled by selection of the frequency to be 
used and the control of the set voltage in the case of alternating current 
discharge and microwave discharge. 
In the present invention, the voltage rise time for gas breakdown is an 
important factor. That is, as an electric field begins to be applied to 
the molecules of the organic compound which is the monomer, polarization 
of the organic compound molecules or acceleration of a trace of electrons 
and ions existing thermally will occur, and the polarization and 
acceleration are gradually enhanced until gas breakdown occurs to form a 
stable plasma state. The time from the application of the electric field 
until the formation of stable plasma state is the voltage rise time for 
gas breakdown, and the length of said time determines the properties of 
the plasma polymerized film formed. 
In the process of the present invention, the voltage rise time for gas 
breakdown is required to be not longer than 100 msec., preferably 10 nsec. 
to 50 msec., more preferably 10 nsec. to 5 msec. If the voltage rise time 
for gas breakdown is longer than 100 msec., no effect of using pulse 
discharging can be obtained and the coefficient of friction of the plasma 
polymerized film obtained cannot be made small. Also, the time of the 
non-discharge condition in pulse discharging must be not shorter than 1 
msec. If the time of the non-discharge condition is shorter than 1 msec., 
the plasma during previous discharging will frequently exist by after-glow 
at the time of the initiation of subsequent pulse discharging, whereby no 
effect of using pulse discharging can be obtained and it is not possible 
to lower the coefficient of friction of the plasma polymerized film 
obtained. The time of the discharge condition in pulse discharging may be 
generally 1 msec. to 10 sec., because the effect of using pulse 
discharging will become smaller if it is too long. 
Other conditions ae not particularly limited. The discharging system 
employed may be any of, for example, direct current discharge, low 
frequency discharge, high frequency discharge and microwave discharge. 
Under typical conditions, the electron temperature of the plasma during 
discharging in the reaction zone of plasma polymerization, specifically, 
for example, in the region 1 to 3 cm apart in the vertical direction from 
the surface of the substrate, may be selected within the range of 
0.5.times.10.sup.4 to 8.times.10.sup.4 K. Here, the electron temperature 
is measured according to the method by use of the probe for measurement of 
plasma characteristics as disclosed in U.S. Pat. No. 4,242,188, and it can 
be controlled to a desired value by changing the applied power for plasma 
excitation, discharging current, the gas pressure of the organic compound 
which is the monomer, the flow rate of said gas, the structure of 
electrodes and the position of the substrate to be treated. The flow rate 
of the gas containing the organic compound which is the monomer flowing 
into the plasma polymerization reactor may be, for example, 0.01 to 500 
ml (STP)/min. per 100 liters of inner volume of the plasma polymerization 
reactor. The temperature of the substrate during plasma polymerization is 
not particularly limited but is generally 0.degree. to 300.degree. C. 
The plasma polymerization reactor used for plasma polymerization is not 
also particularly limited and any of internal electrode system and 
electrodless system may be available, and there is also no limitation with 
respect to the shape of electrode coils, or cavity or antenna structure in 
the case of microwave discharging. Conventional devices used for plasma 
polymerization can be utilized. 
The organic compound which may be used as the monomer in the process of the 
present invention is not particularly limited, provided that it is a gas 
under the above-mentioned pressure for generating low temperature plasma. 
The organic compounds include substituted or unsubstituted hydrocarbon 
compounds and organometallic compounds. Examples of hydrocarbon compounds 
are saturated or unsaturated aliphatic or alicyclic hydrocarbons and 
aromatic hydrocarbons, and these may have substituents such as halogen 
atoms, including fluorine, chlorine, bromine and iodine, hydroxyl group, 
amino group, carboxyl group, mercapto group, amido group, imido group and 
others, and they may also contain ether linkages. 
More specifically, aliphatic hydrocarbons include, for example, alkanes 
such as methane, ethane, propane, butane, pentane, hexane and the like; 
alkenes such as ethene, propene, butene, pentene and the like; dienes such 
as butadiene, isoprene, pentadiene, hexadiene and the like; alkynes such 
as acetylene, vinylacetylene and the like. Alicyclic hydrocarbons include, 
for example, cyclopropane, cyclobutane, cyclopentane and the like. 
Aromatic hydrocarbons include, for example, benzene, styrene, toluene, 
xylene, pyridine, thiophene, pyrrole, aniline, phenylenediamine, 
toluidine, benzenesulfonic acid, ethylbenzene, acetophenone, 
chlorobenzene, methyl benzoate, phenyl acetate, phenol, cresol, furan and 
the like. 
Organic compounds which are particularly preferred for obtaining plasma 
polymerized films with low coefficient of friction are alkanes and 
halogenated alkanes, and the voltage rise time for gas breakdown should 
preferably be 10 nsec. to 5 msec. Alkanes preferably have 1 to 10 carbon 
atoms, more preferably 3 to 8 carbon atoms, as exemplified by methane, 
ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane 
and isomers of these. Among them, particularly preferred are propane, 
n-butane, n-pentane, n-hexane, n-heptane and n-octane. Halogenated alkanes 
are those in which at least one hydrogen atom in alkanes is substituted by 
a halogen atom such as fluorine, chlorine, bromine or iodine, preferably 
fluorine atom or chlorine atom, having preferably 1 to 10 carbon atoms, 
more preferably 2 to 6 carbon atoms. Such halogenated alkanes include, for 
example, monofluoromethane, difluoromethane, trifluoromethane, 
tetrafluoromethane, monochloromethane, dichloromethane, trichloromethane, 
tetrachloromethane, monofluorodichloromethane, monofluoroethane, 
trifluoroethanes, tetrafluoroethanes, pentafluoroethane, hexafluoroethane, 
dichloroethanes, tetrachloroethanes, hexachloroethane, 
difluorodichloroethanes, trifluorotrichloroethanes, monofluoropropanes, 
trifluoropropanes, pentafluoropropanes, perfluoropropane, 
dichloropropanes, tetrachloropropanes, hexachloropropanes, 
perchloropropane, difluorodichloropropanes, tetrafluorodichloropropanes, 
bromomethane, methylene dibromide, bromoform, carbon tetrabromide, 
tetrabromoethanes, pentabromoethane, methyl iodide, diiodomethane, 
monofluorobutanes, trifluorobutanes, tetrafluorobutanes, 
octafluorobutanes, difluorobutanes, monofluoropentanes, 
pentafluoropentanes, octachloropentanes, perchloropentanes, 
trifluorotrichloropentanes, tetrafluorohexanes, nonachlorohexanes, 
pentafluorotrichlorohexanes, tetrafluoroheptanes, hexafluoroheptanes, 
trifluoropentachloroheptanes, difluorooctanes, pentafluorooctanes, 
difluorotetrafluorooctanes, monofluorononanes, hexafluorononanes, 
decachlorononanes, heptafluorohexachlorononanes, difluorodecanes, 
pentafluorodecanes, tetrachlorodecanes, tetrafluorotetrachlorodecanes, 
octadecachlorodecanes and the like. Particularly preferable halogenated 
alkanes are monofluoroethane, difluoroethanes, trifluoroethanes, 
tetrafluoroethanes, pentafluoroethane, monofluoropropanes, 
difluoropropanes, trifluoropropanes, tetrafluoropropanes, 
pentafluoropropanes, monofluoropropanes, difluorobutanes, 
trifluorobutanes, tetrafluorobutanes and pentafluorobutanes. 
Also, preferred as organic compounds for obtaining plasma polymerized films 
with particularly low coefficient of friction are halogenated unsaturated 
hydrocarbons such as monofluoroethylene, difluoroethylenes, 
trifluoroethylene, tetrafluoroethylene, monochloroethylene, 
dichloroethylenes, trichloroethylene, tetrachloroethylene, 
monofluorobenzene, difluorobenzenes, tetrafluorobenzenes, 
hexafluorobenzene and the like. For these compounds, the voltage rise time 
for gas breakdown is preferably 10 nsec. to 5 msec. 
According to the continuous plasma polymerization process of the prior art, 
it has been impossible to obtain a plasma polymerized film enriched in 
aromatic rings, because aromatic rings will be destroyed during the 
polymerization process even if an aromatic hydrocarbon such as styrene may 
be used as the organic compound which is the monomer. Also, it has been 
impossible to obtain a plasma polymerized film enriched in functional 
groups such as amino group or hydroxyl group, because these functional 
groups will also be destroyed in the polymerization process even if 
organic amines or alcohols having such functional groups may be used as 
the organic compound which is the monomer. In contrast, the process of the 
present invention is advantageous in that when an aromatic hydrocarbon is 
used as the monomer, there can be obtained a plasma polymerized film with 
low coefficient of friction and enriched in aromatic rings, while, when a 
compound having functional groups is used as the monomer, there can be 
obtained a plasma polymerized film with low coefficient of friction and 
enriched in the functional groups. 
The plasma polymerized film enriched in aromatic rings has permselectivity 
for aromatic hydrocarbons and therefore, for example, it is useful as a 
separation membrane for separating styrene from a mixture of styrene and 
methanol. Preferable aromatic hydrocarbons for obtaining such a plasma 
polymerized film include, for example, benzene, styrene, phenol, toluene, 
xylene, chlorobenzene and the like. For these compounds, the voltage rise 
time for gas breakdown is preferably 1 .mu.sec. to 4 msec. 
The plasma polymerized film enriched in amino groups or mercapto groups has 
biocompatibility, and therefore it is suitable for surface coating of cell 
cultivation bed, artificial organs, artificial blood vessels, artificial 
bones, carriers for diagnostic reagents, biosensors, etc. Preferable 
organic amines for obtaining such a plasma polymerized film include, for 
example, ethylamine, methylamine, propylamine, ethylenediamine, 
allylamine, aniline, phenylenediamine, toluidine, hexamethylenediamine and 
the like. Examples of mercaptans are methylmercaptan, ethylmercaptan and 
the like. For these compounds, the voltage rise time for gas breakdown is 
preferably 1 .mu.sec. to 25 .mu.sec. According to the continuous plasma 
polymerization of the prior art, when employing a compound with low 
molecular weight such as ethylamine, methylmercaptan, etc., as the 
monomer, it has been particularly difficult to permit amino group or 
mercapto group to remain in the plasma polymerized film. However, the 
process of the present invention is advantageous in giving a film enriched 
in these functional groups by use of these monomers, because use of these 
organic compounds with low molecular weights as the monomer can give the 
advantages such that the amount of the monomer flowing into the plasma 
polymerization reactor can be controlled with ease due to the greater 
vapor pressure thereof and also that a uniform film with large area can be 
obtained due to rapid gas diffusion velocity. 
The plasma polymerized film enriched in hydroxyl group or carboxyl group is 
highly hydrophilic and therefore it is useful for surface coating of 
articles for which wettability with water is demanded, such as contact 
lens. Also, it is useful for improvement of coating, dyeing and adhesion 
characteristics by modification of the surface of plastic moldings. 
Preferable organic compounds for obtaining such a plasma polymerized film 
are compounds having hydroxyl groups or carboxyl groups, as exemplified by 
alcohols such as methanol, ethanol, ethylene glycol, isopropanol, butanol 
and the like; hydroxybenzenes and hydroxyalkylbenzenes such as phenol, 
pyrocatechin, resorcin, hydroquinone, pyrogallol, cresol and the like; 
carboxylic acids such as formic acid, acetic acid, propionic acid, acrylic 
acid, oxalic acid, malonic acid, succinic acid, glycolic acid, lactic acid 
and the like. For these compounds, the voltage rise time for gas breakdown 
is preferably 10 nsec. to 1 .mu.sec. 
Organometallic compounds which may be used in the process of the present 
invention include, for example, those containing tin, silicon, germanium, 
aluminum, magnesium, calcium, zinc, cadmium, beryllium, lead, etc., as the 
metal element. Typical examples of the compounds include organic tin 
compounds such as tetramethyltin and the like; organic silicon compounds 
such as tetramethylsilane, trimethylsilane and the like. When these 
organometallic compounds are used as the monomer, the voltage rise time 
for gas breakdown is preferably 1 nsec. to 1 .mu.sec., whereby there is 
the advantage that a plasma polymerized film which has smooth surface like 
a metal having a low coefficient of friction and a metallic luster can be 
obtained. 
The above organic compounds may be used either singly or in combination of 
two or more compounds. When employing a combination of two or more organic 
compound gases, a gas mixture of the respective gases may be introduced 
into the plasma polymerizer, or alternatively they can be introduced 
separately into the plasma polymerizer and mixed in the polymerizer. Also, 
the gases containing these organic compounds provided for plasma 
polymerization may be mixed with a carrier gas of an inert gas such as 
argon, helium, xenon, neon and the like before introduction into the 
plasma polymerization reactor. Further, to the gases may be added, as 
required, gases such as nitrogen, hydrogen, oxygen, carbon monoxide, 
carbon dioxide, nitrogen monoxide, nitrogen dioxide, sulfur hexafluoride, 
fluorine. 
In the process of the present invention, the plasma polymerized film is 
formed on the surface of a substrate placed in the reaction zone of plasma 
polymerization. The substrate may include, in addition to the examples as 
already mentioned, magnetic recording media such as magnetic tapes, 
magnetic discs and the like. Particularly, a thin metal film type magnetic 
recording medium in which the magnetic recording layer formed on a 
non-magnetic support comprises a thin metal film (e.g. thin cobalt (film) 
has a large coefficient of friction due to the thin metal film. Therefore, 
it is markedly effective to employ the plasma polymerized film according 
to the present invention. Also, Japanese Laid-open Patent Publication No. 
179632/1984 discloses a process for forming a protective film on the 
surface of a magnetic recording medium according to plasma polymerization. 
It is also possible to enhance lubricity by forming further plasma 
polymerized film according to the process of the present invention on such 
a protective film thereby further enhancing the durability of such 
magnetic recording media. Examples of the substrate include structural 
elements such as gears, shafts, bearings, cams, pistons, cylinders, 
chains, wires, etc. made of metals, plastics or ceramics; members such as 
heads, guide poles, reels for videos or tape recorders; outer surfaces of 
ship or boats and various screws; inner surfaces of hoses; inner surfaces 
of various pumps; inner nozzle surfaces of extruders; surfaces of O-rings 
for shielding of movable portions; surfaces of skiing plates, artificial 
joints and other articles. Thus, coefficient of friction of the sliding 
surfaces of these substrates can be made smaller by the plasma polymerized 
film formed thereon. 
According to the process of the present invention, a plasma polymerized 
film can be formed uniformly with a thickness of 3 .ANG. to 1 .mu.m on the 
surface of a substrate disposed in the reaction zone by plasma 
polymerization for about 1 minute to 1 hour. The plasma polymerized film 
has practical durability even when it is a very thin film with an average 
thickness of about 3 to 50 .ANG.. 
The process of the present invention is now described in more detail by 
referring to the following examples, to which the present invention is not 
limited. 
EXAMPLES 
Examples 1-11, Comparative Examples 1-18 
By means of the device shown in FIG. 2, a plasma polymerized film was 
formed on the surface of the substrate tape for magnetic recording media. 
The device shown in FIG. 2 has a pair of electrodes 3 and 4 opposed to 
each other in a plasma polymerization reactor 2 connected to a vacuum pump 
1 and these electrodes are connected to an alternate current power source 
(20 KHz) 5. The alternate power source is equipped with a function 
generator and an amplifier, and pulsing is possible by the burst control 
of the function generator. The voltage rise time for gas breakdown in 
pulse discharging is controlled to 12.5 .mu.sec. Pipes 6, 7 and 8 for 
feeding gaseous organic compounds are connected to the plasma 
polymerization reactor 2 at the bottom thereof. These feeding pipes for 
organic compounds are equipped with flow rate controlling valves (not 
shown). At the side wall of the plasma polymerization reactor 2, there is 
provided a pressure gauge (not shown) for monitoring the gas pressure 
within the polymerization reactor. The substrate tape 11 for magnetic 
recording media to be treated wound up on a first roll 9 runs continuously 
between the two electrodes 3 and 4 during operation and is wound up on a 
second roll 10. In the region between the electrodes 3 and 4, the 
aforementioned probe 12 disclosed in U.S. Pat. No. 4,242,188 is disposed 
at the position 2 cm apart from the tape to be treated. 
In the operation of this device, one or more monomer compounds are fed 
under gaseous state while evacuating the inside of the plasma 
polymerization reactor 2 by means of a vacuum pump. When plasma is excited 
by discharging between the electrodes 3 and 4, a plasma polymerized film 
is formed on the surface of the substrate tape 11 running between the 
electrodes. The electron temperature of the plasma in the reaction zone is 
measured by the probe 12, and it is controlled to a desired value by 
changing the discharging current, the gas pressure in the plasma 
polymerization reactor, the flow rates of the monomer compounds and so on. 
In these Examples and Comparative Examples, a long 
polyethyleneterephthalate film with a thickness of 12 .mu.m and a width of 
10 cm obliquely vapor deposited with a thin cobalt-nickel magnetic film 
(nickel content; 20 weight %) with a thickness of 100 nm on the surface 
thereof was used as the substrate tape for magnetic recording media and a 
plasma polymerized film was formed by means of the device shown in FIG. 2 
on the thin cobalt-nickel magnetic layer to obtain a magnetic recording 
medium. In Examples 1 and 2 and Comparative Examples 1 and 2, a single 
layer plasma polymerized film was formed on the substrate tape, while in 
Examples 3, 4 and 5 and Comparative Examples 3 and 4, after formation of a 
first layer of plasma polymerized film, a second layer of plasma 
polymerized film of a different kind was formed as the overlayer thereon. 
The plasma polymerization conditions in respective Examples and Comparative 
Examples, namely the kinds and flow rates of organic compounds, 
discharging system, discharging current (in the case of pulse discharging, 
current during the time of discharge condition), running speed of the 
substrate tape and the thickness of the plasma polymerized film formed are 
shown in Table 1 and Table 2. Table 1 concerns the case of forming a 
single layer of plasma polymerized film and the first layer (lower layer) 
in the case of forming two layers, and Table 2 concerns the second layer 
(upper layer) in the case of forming two layers. In Table 1 and Table 2, 
the thickness of the plasma polymerized film was evaluated by measuring 
the plasma polymerized film formed on the surface of a silicon wafer run 
simultaneously with the substrate tape by means of an ellipsometer and 
regarding the measured value as the thickness of the plasma polymerized 
film formed on the substrate tape. 
The coefficient of dynamic friction (.mu.) of the surface of the magnetic 
recording medium tape having the plasma polymerized film formed on its 
surface as described above was measured by the method shown in FIG. 3. In 
this method, a tape 22 mounted with a weight 21 of 50 g at one end was 
hanged at the upper half of a fixed stainless steel rod (SUS 420 J) 23 of 
50 mm in diameter, led downward vertically and thereafter, through a 
freely rotatable roll 24, in the horizontal direction and connected at the 
other end to a tension detector 25. The tension detector 25 is equipped 
with a mechanism capable of tensioning and relaxing the tape and 
reciprocates the tape 22 with a stroke of 5 cm at a speed of 20 mm/sec. 
During going (when the tape 22 is drawn toward the tension detector), the 
tension T.sub.2 is measured and the coefficient of dynamic friction is 
determined according to the following formula T.sub.2 /T.sub.1 =exp 
(.mu..pi.) wherein T.sub.1 =50 g (load by the weight 21). 
According to the above method, the initial value of the coefficient of 
dynamic friction in the contact between the magnetic recording medium tape 
surface having the plasma polymerized film formed thereon and the 
stainless steel rod and the coefficient of dynamic friction after 
reciprocating the tape 22 1000 times by means of the device shown in FIG. 
3 were measured. Also, by observation of the tape surface after 1000 times 
reciprocation with naked eyes and by an optical microscope (.times.100), 
the state in which abraded matters were sticked on the stainless steel rod 
23 was examined. The results of these measurements are shown in Table 3. 
TABLE 1 
__________________________________________________________________________ 
Formation of single layer or first layer plasma polymerized film*.sup.1 
Running 
Thickness 
Discharging*.sup.2 
Discharging current 
speed of 
of plasma 
conditions under discharge 
substrate 
polymerized 
Organic compound 
Gas flow rate 
(Non-discharge time- 
condition tape film 
(molar ratio) 
(ml(STP)/min.) 
discharge time, sec.) 
(mA) (m/min.) 
(.ANG.) 
__________________________________________________________________________ 
Example 1 
CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.3 
30 Pulse (1-1) 
50 0.25 80 
Example 2 
CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.3 
30 Pulse (5-1) 
50 0.20 90 
Example 3 
CH.sub.4 + CF.sub.4 (1:1) 
20 Continuous 120 0.15 80 
Example 4 
CH.sub.4 + CF.sub.4 (1:1) 
20 " 120 0.15 80 
Example 5 
CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.3 
30 " 100 0.2 20 
Example 6 
CH.sub.2 CH.sub.2 
30 Pulse (0.5-0.5) 
100 0.20 100 
Example 7 
CH.sub.2 CHCHCH.sub.2 
30 " 90 0.10 90 
Example 8 
C.sub.6 H.sub.12 
30 " 70 0.15 90 
Example 9 
C.sub.6 H.sub.6 
30 " 80 0.10 80 
Example 10 
CF.sub.2 CF.sub.2 
30 " 80 0.10 90 
Example 11 
CH.sub.2 CHCOOH 
30 " 80 0.15 80 
Comparative 
CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.3 
30 Continuous 70 0.3 100 
Example 1 
Comparative 
CH.sub.2 .dbd.CH--CH.dbd.CH.sub.2 
30 " 60 0.3 100 
Example 2 
Comparative 
CH.sub.4 + CF.sub.4 (1:1) 
20 " 120 0.15 80 
Example 3 
Comparative 
CH.sub.2 .dbd.CH--CH.dbd.CH.sub.2 
25 " 70 0.3 90 
Example 4 
Comparative 
C.sub.4 H.sub.10 
30 Pulse (0.0005-0.0005) 
150 0.25 100 
Example 5 
Comparative 
CH.sub.4 + CF.sub.4 (1:1) 
30 " 120 0.20 120 
Example 6 
Comparative 
CH.sub.2 CHCHCH.sub.2 
30 " 90 0.10 100 
Example 7 
Comparative 
C.sub.6 H.sub.12 
30 " 70 0.15 110 
Example 8 
Comparative 
C.sub.6 H.sub.6 
30 " 80 0.10 110 
Example 9 
Comparative 
CF.sub.2 CF.sub.2 
30 " 80 0.10 120 
Example 10 
Comparative 
CH.sub.2 CHCOOH 
30 Pulse 80 0.15 90 
Example 11 
Comparative 
C.sub.4 H.sub.10 
30 Continuous 150 0.25 120 
Example 12 
Comparative 
CH.sub.4 + CF.sub.4 (1:1) 
30 " 120 0.20 120 
Example 13 
Comparative 
CH.sub.2 CHCHCH.sub.2 
30 " 90 0.10 100 
Example 14 
Comparative 
C.sub.6 H.sub.12 
30 " 70 0.15 110 
Example 15 
Comparative 
C.sub.6 H.sub.6 
30 " 80 0.10 110 
Example 16 
Comparative 
CF.sub.2 CF.sub.2 
30 " 80 0.10 120 
Example 17 
Comparative 
CH.sub.2 CHCOOH 
30 " 80 0.15 90 
Example 18 
__________________________________________________________________________ 
Remarks: 
*.sup.1 Inner pressure in the plasma polymerization reactor during plasma 
polymerization are all 50 mTorr. The electron temperature of plasma 
(provided during the time of discharge condition in the case of pulse 
discharging) is controlled to within 0.5 .times. 10.sup.4 to 8 .times. 
10.sup.4 K. 
*.sup.2 The voltage rise time for gas breakdown is 12.5 sec. Nondischarge 
time means the time for nondischarge condition in pulse discharging. 
Discharge time means the time for discharge condition in pulse 
discharging. 
TABLE 2 
__________________________________________________________________________ 
Formation of second layer plasma polymerized film*.sup.1 
Thickness 
Whole 
Discharging*.sup.2 
Discharging 
Running 
of plasma 
thickness 
Organic Gas flow 
conditions 
current under 
speed of 
polymerized 
of plasma 
compound rate (Non-discharge 
discharge 
substrate 
film (2nd 
polymerized 
(molar (ml(STP)/- 
time-discharge 
condition 
tape layer) films 
ratio) min.) time, sec.) 
(mA) (m/min.) 
(.ANG.) 
(.ANG.) 
__________________________________________________________________________ 
Example 1 
-- 0 80 
Example 2 
-- 0 90 
Example 3 
CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.3 
30 Pulse (1-1) 
50 0.5 40 120 
Example 4 
CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.3 
30 Pulse (5-1) 
50 0.4 45 125 
Example 5 
CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.3 
30 " 60 0.7 30 100 
Example 6 
-- 0 100 
Example 7 
-- 0 90 
Example 8 
-- 0 90 
Example 9 
-- 0 80 
Example 10 
-- 0 90 
Example 11 
-- 0 80 
Comparative 
-- 0 100 
Example 1 
Comparative 
-- 0 100 
Example 2 
Comparative 
CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.3 
30 Continuous 
70 0.9 30 110 
Example 3 
Comparative 
CH.sub.2 .dbd.CHCH.dbd.CH.sub.2 
25 " 70 1.0 20 110 
Example 4 
Comparative 
-- 0 100 
Example 5 
Comparative 
-- 0 120 
Example 6 
Comparative 
-- 0 100 
Example 7 
Comparative 
-- 0 110 
Example 8 
Comparative 
-- 0 110 
Example 9 
Comparative 
-- 0 120 
Example 10 
Comparative 
-- 0 90 
Example 11 
Comparative 
-- 0 120 
Example 12 
Comparative 
-- 0 120 
Example 13 
Comparative 
-- 0 100 
Example 14 
Comparative 
-- 0 110 
Example 15 
Comparative 
-- 0 110 
Example 16 
Comparative 
-- 0 120 
Example 17 
Comparative 
-- 0 90 
Example 18 
__________________________________________________________________________ 
Remarks: 
*.sup.1 Inner pressure in the plasma polymerization reactor during plasma 
polymerization are all 50 mTorr. The electron temperature of plasma 
(provided during the time of discharge condition in the case of pulse 
discharging) is controlled to within 0.5 .times. 10.sup.4 to 8 .times. 
10.sup.4 K 
*.sup.2 The voltage rise time for gas breakdown is 12.5 sec. 
TABLE 3 
______________________________________ 
Coefficient of 
Result of*.sup.1 
Initial value 
dynamic friction 
observation of 
of coefficient 
after 1000 times 
abrasion after 1000 
of dynamic 
reciprocal times 
friction (.mu.) 
friction (.mu.) 
reciprocal friction 
______________________________________ 
Example 1 
0.23 0.25 A 
Example 2 
0.22 0.25 A 
Example 3 
0.23 0.24 A 
Example 4 
0.23 0.25 A 
Example 5 
0.22 0.26 A 
Example 6 
0.28 0.30 A 
Example 7 
0.29 0.31 A 
Example 8 
0.24 0.26 A 
Example 9 
0.28 0.30 A 
Example 10 
0.19 0.21 A 
Example 11 
0.22 0.24 A 
Comparative 
0.43 &gt;0.7 B 
Example 1 
Comparative 
0.45 &gt;0.7 B 
Example 2 
Comparative 
0.51 &gt;0.7 B 
Example 3 
Comparative 
0.42 &gt;0.7 B 
Example 4 
Comparative 
0.38 0.47 B 
Example 5 
Comparative 
0.42 0.60 B 
Example 6 
Comparative 
0.44 0.55 B 
Example 7 
Comparative 
0.39 0.44 B 
Example 8 
Comparative 
0.38 0.57 B 
Example 9 
Comparative 
0.32 0.45 B 
Example 10 
Comparative 
0.34 0.40 B 
Example 11 
Comparative 
0.39 &gt;0.7 B 
Example 12 
Comparative 
0.44 &gt;0.7 B 
Example 13 
Comparative 
0.45 &gt;0.7 B 
Example 14 
Comparative 
0.40 &gt;0.7 B 
Example 15 
Comparative 
0.40 &gt;0.7 B 
Example 16 
Comparative 
0.35 &gt;0.7 B 
Example 17 
Comparative 
0.37 &gt;0.7 B 
Example 18 
______________________________________ 
Remarks: 
*.sup.1 A: No abraded matter recognized by optical microscope. 
B: Adherent of white powdery abraded matter recognized with naked eyes. 
EXAMPLE 12 
By means of the Bell-jar type plasma polymerization reactor shown in FIG. 
4, plasma polymerized film from propane was formed by plasma 
polymerization by pulse discharging on the surface of a disc made of 
copper with a diameter of 50 mm and a thickness of 5 mm. 
The plasma polymerization reactor 31 shown in FIG. 4 has parallel flat 
plate type electrodes 32 and 32', and these electrodes are connected to 
the power source 33 outside of the polymerization reactor. A pipe 35 for 
feeding a gaseous monomer compound is connected to the plasma 
polymerization reactor 31 at its bottom, and this pipe 35 is provided with 
a gas flow rate controlling valve 37. A vacuum pump (not shown) is 
connected through an evacuating pipe 34 to the plasma polymerization 
reactor at another site of the bottom, and the pipe 34 is provided with a 
valve 36 for controlling gas evacuating level. The plasma polymerization 
reactor 31 is equipped at its side wall with a pressure gauge for 
monitoring the pressure in the vessel. 
The above copper disc is disposed as the substrate 39 between the 
electrodes 32 and 32', and the probe 40 disclosed in U.S. Pat. No. 
4,242,188 is disposed at a position 2 cm apart from the substrate 39 for 
measuring the electron temperature of plasma. 
In this Example, plasma polymerization was carried out by application of an 
alternate current of 20 KHz for 3 minutes under the conditions of a flow 
rate of propane of 10 ml (STP)/min., a pressure in the plasma 
polymerization reactor of 50 mTorr, pulse conditions: 0.8 sec. of the time 
of the discharge condition in pulse discharging, 0.2 sec. of the time of 
non-discharge condition, 12.5 .mu.sec. of the voltage rise time for gas 
breakdown and 100 mA of discharging current during discharging. During 
this operation, the electron temperature of the plasma during the time of 
discharging was found to be 0.5.times.10.sup.4 to 8.times.10.sup.4 K. As a 
result, a plasma polymerized film with a thickness of 200 .ANG. was formed 
on the surface of the copper disc. The film thickness was estimated by 
measuring the thickness of the plasma polymerized film formed on the 
surface of silicon wafer with a diameter of 50 mm and a thickness of 300 
.mu.m placed nearby the copper disc by an ellipsometer and regarding the 
measured thickness as that of the plasma polymerized film formed on the 
copper disc. 
The coefficient of dynamic friction of the surface of the copper disc 
having the plasma polymerized film thus formed on its surface was measured 
as follows. That is, a hemisphere made of copper of 2 mm in diameter was 
mounted on one end of a rod, and the tip of the rod, namely said 
hemisphere, was urged under a load of 100 g weight vertically against the 
copper disc having the plasma polymerized film thereon at a distance of 20 
mm from the center, and the coefficient of dynamic friction of the copper 
disc having the plasma polymerized film thereon was determined by 
measuring the force applied in the lateral direction on the rod while 
rotating the copper disc at 100 rpm. The coefficient of dynamic friction 
was measured at several temperatures of the copper disc and the copper 
hemisphere in contact therewith within the range of from 20.degree. C. to 
200.degree. C., and the relationship between the coefficient of dynamic 
friction and temperature was examined. The results are shown in Table 4. 
EXAMPLES 13-15 
Plasma polymerized films were formed on the surface of copper discs in the 
same manner as in Example 12 except for changing the conditions of pulse 
discharging as shown in Table 4. The thicknesses of the plasma polymerized 
films formed in these Examples are also shown in Table 4. The coefficient 
of dynamic friction of the surfaces of the discs having thus formed plasma 
polymerized films on the surfaces were measured at various temperatures 
according to the same method as in Example 12. The results are shown in 
Table 4. 
TABLE 4 
__________________________________________________________________________ 
Pulse discharging conditions 
Time of Time of 
Plasma 
Thickness 
discharge non-discharge 
polymeri- 
of plasma 
condition condition 
zation time 
polymerized 
Coefficient of dynamic friction (.mu.) 
(sec.) (sec.) (min.) 
film (.ANG.) 
20 (.degree.C.) 
40 60 80 100 
120 
140 
160 
200 
240 
__________________________________________________________________________ 
Example 12 
0.8 0.2 3 200 0.07 0.07 
0.07 
0.06 
0.07 
0.08 
0.09 
0.10 
0.11 
0.12 
Example 13 
7 1 3 120 0.11 0.10 
0.11 
0.10 
0.11 
0.11 
0.12 
0.12 
0.13 
0.13 
Example 14 
0.3 0.2 1.8 240 0.12 0.11 
0.12 
0.11 
0.11 
0.11 
0.12 
0.13 
0.14 
0.14 
Example 15 
0.03 0.02 1.5 210 0.18 0.17 
0.18 
0.16 
0.17 
0.17 
0.17 
0.16 
0.18 
0.19 
__________________________________________________________________________ 
Note: 
The voltage rise times for gas breakdown are all 12.5 .mu.sec. 
EXAMPLES 16-39 AND COMATIVE EXAMPLES 19 AND 20 
Plasma polymerized films were formed on the surface of copper discs in the 
same manner as in Example 12 except that the conditions of pulse 
discharging were changed as shown in Table 5 and the gas pressure in the 
plasma polymerization reactor and polymerization time were changed to 500 
mTorr and 1 hour, respectively. The thicknesses of the plasma polymerized 
films formed in the respective Examples and Comparative Examples are also 
shown in Table 5. The coefficient of dynamic friction of the surfaces of 
the copper discs having thus formed plasma polymerized films on the 
surfaces were measured at various temperatures according to the same 
method as in Example 12. The results are shown in Table 6. 
TABLE 5 
__________________________________________________________________________ 
Pulse discharging Thickness of 
conditions 
Discharging current 
plasma 
Organic 
Power 
Voltage rise time 
(cycle-discharge 
under discharge 
polymerized 
compound 
source 
for gas breakdown 
time) (sec.) 
condition (mA) 
film (.ANG.) 
__________________________________________________________________________ 
Example 16 
C.sub.4 H.sub.10 
DC 10 nsec. 1-0.5 100 5200 
Example 17 
" " 1 .mu.sec. 
" " 4800 
Example 18 
" " 100 .mu.sec. 
" " 5000 
Example 19 
" " 1 msec. " " 5100 
Example 20 
" " 4 msec. " " 4800 
Example 21 
" " 50 msec. " " 4300 
Comparative 
" " 130 msec. " " 4200 
Example 19 
Example 22 
" AC 250 nsec. (1 MHz) 
" 150 6300 
Example 23 
" " 2.5 .mu.sec. (100 KHz) 
" 130 6000 
Example 24 
" " 12.5 .mu.sec. (20 KHz) 
" 120 6100 
Example 25 
" " 250 nsec. (1 KHz) 
" 100 5800 
Example 26 
" " 2.5 msec. (100 Hz) 
" " 5500 
Example 27 
" " 5 msec. (50 Hz) 
" " 4800 
Example 28 
C.sub.2 F.sub.4 
DC 10 nsec. " 70 7000 
Example 29 
" " 1 .mu.sec. 
" " 6800 
Example 30 
" " 100 .mu.sec. 
" 60 7000 
Example 31 
" " 1 msec. " " 7200 
Example 32 
" " 4 msec. " " 6800 
Example 33 
" " 50 msec. " " 6500 
Comparative 
" " 130 msec. " " 6300 
Example 20 
Example 34 
" AC 250 nsec. (1 MHz) 
" 100 8100 
Example 35 
" " 2.5 .mu.sec. (100 KHz) 
" 90 7700 
Example 36 
C.sub.2 H.sub.4 
" 12.5 .mu.sec. (20 KHz) 
" 85 7800 
Example 37 
" " 250 .mu.sec. (1 KHz) 
" 80 7500 
Example 38 
" " 2.5 msec. (100 Hz) 
" 70 7000 
Example 39 
" " 5 msec. (50 Hz) 
" " 7100 
__________________________________________________________________________ 
TABLE 6 
______________________________________ 
Coefficient of 
dynamic friction 
(.mu.) 
20.degree. C. 
100.degree. C. 
200.degree. C. 
______________________________________ 
Example 16 0.07 0.07 0.11 
Example 17 0.08 0.09 0.13 
Example 18 0.08 0.08 0.12 
Example 19 0.09 0.09 0.13 
Example 20 0.10 0.11 0.13 
Example 21 0.37 0.37 0.39 
Comparative 0.44 0.45 0.48 
Example 19 
Example 22 0.07 0.07 0.10 
Example 23 0.08 0.09 0.11 
Example 24 0.07 0.09 0.10 
Example 25 0.09 0.10 0.12 
Example 26 0.10 0.12 0.14 
Example 27 0.11 0.13 0.15 
Example 28 0.06 0.06 0.06 
Example 29 0.05 0.06 0.06 
Example 30 0.06 0.06 0.07 
Example 31 0.07 0.06 0.07 
Example 32 0.07 0.07 0.08 
Example 33 0.25 0.29 0.33 
Comparative 0.30 0.37 0.45 
Example 20 
Example 34 0.06 0.06 0.07 
Example 35 0.07 0.07 0.07 
Example 36 0.07 0.08 0.08 
Example 37 0.07 0.08 0.09 
Example 38 0.08 0.08 0.10 
Example 39 0.09 0.09 0.14 
______________________________________ 
EXAMPLES 40-45, COMATIVE EXAMPLES 21-23 
Under the following conditions, according to the same procedure as in 
Example 12, plasma polymerized films were formed on the surfaces of copper 
discs (diameter 50 mm, thickness 5 mm) and silicon wafers (diameter 50 mm, 
thickness 300 .mu.m). 
Power source: DC power source, 
Organic compound: ethylamine (flow rate 10 ml (STP)/min.), 
Pressure: 100 mTorr, 
Time of discharge condition in pulse discharging: 10 msec., 
Time of non-discharge condition in pulse discharging: 40 msec., 
Current during the time of discharge condition: 100 mA, 
Polymerization time: 1 hr, 
Electron temperature during the time of discharge condition: 
3.7.times.10.sup.4 to 4.0.times.10.sup.4 K. 
Under the same conditions as shown above except for changing the voltage 
rise time for gas breakdown to 2 msec., 4 msec., 6 msec., 8 msec., 10 
msec. and 12 msec., plasma polymerized films were formed on the surfaces 
of copper discs and silicon wafers. 
As Comparative Examples, under the same conditions as shown above except 
for effecting continuous discharging in place of pulse discharging at 
discharging current of 50 mA, 100 mA and 200 mA, plasma polymerized films 
were formed on the surfaces of copper discs and silicon wafers. 
The thicknesses of the plasma polymerized films were determined by 
measuring those of the plasma polymerized film formed on the silicon 
wafers by means of an ellipsometer, and also the films were analyzed by 
Fourier Transform Infrared Spectroscopy (FT-IR) according to the 
transmission method. Prior to analysis, the FT-IR device was replaced 
internally with dry argon gas so that OH absorption exhibited by water may 
not appear in the IR spectrum. The area of the absorption band in the 
region of from 3300 to 3500 cm.sup.-1 by amino group was measured. The 
relative values of the band areas in respective experiments were 
determined, taking the band area in the experiment in which continuous 
discharging was effected at a discharging current of 100 mA to be 1. The 
relative values obtained were estimated as representing relatively the 
contents of amino group. The results are shown in Table 7. The coefficient 
of dynamic friction of the surfaces of the copper discs having thus formed 
plasma polymerized films on their surfaces were measured at 20.degree. C. 
according to the same method as in Example 12. The results are shown in 
Table 7. 
TABLE 7 
__________________________________________________________________________ 
Discharging conditions 
Plasma polymerized film 
Voltage rise 
Discharging Coefficient 
time for gas 
current under 
Content of dynamic 
Discharging 
breakdown 
discharge 
of amino 
Thickness 
friction 
system 
(msec.) 
condition (mA) 
group 
(.ANG.) 
(.mu.) 
__________________________________________________________________________ 
Example 40 
Pulse 2 100 6.5 4700 0.29 
Example 41 
" 4 " 3.0 4500 0.30 
Example 42 
" 6 " 1.6 4600 0.34 
Example 43 
" 8 " 1.1 4400 0.35 
Example 44 
" 10 " 0.9 4200 0.37 
Example 45 
" 12 " 1.0 4400 0.37 
Comparative 
Continuous 
-- 50 0.8 5400 0.45 
Example 21 
Comparative 
" -- 100 1.0 5800 0.47 
Example 22 
Comparative 
" -- 200 0.9 6300 0.46 
Example 23 
__________________________________________________________________________ 
EXAMPLES 46-49, COMATIVE EXAMPLES 24-26 
Under the following conditions, according to the same procedure as in 
Example 12, a plasma polymerized film was formed on the surface of a 
silicon wafer (diameter 50 mm, thickness 300 .mu.m). 
Power source: AC power source, 
Organic compound: styrene (flow rate 10 ml (STP)/min.), 
Pressure: 50 mTorr, 
Time of discharge condition in pulse discharging: 10 msec., 
Time of non-discharge condition in pulse discharging: 40 msec., 
Current during the time of discharge condition: 100 mA, 
Polymerization time: 1 hr, 
Electron temperature during the time of discharge condition: 
3.2.times.10.sup.4 to 3.8.times.10.sup.4 K. 
Under the same conditions as shown above except for changing the voltage 
rise time for gas breakdown to 12.5 .mu.sec., 16 .mu.sec., 25 .mu.sec. and 
50 .mu.sec., plasma polymerized films were formed on the surfaces of 
silicon wafers. Pulsing of applied power was effected by burst control of 
a low frequency generator (function generator), and the voltage rise time 
for gas breakdown was changed by changing the frequency of the power 
source to 5, 10, 15 and 20 KHz. 
As Comparative Examples, under the same conditions as shown above except 
for effecting continuous discharging in place of pulse discharging at 
discharging current of 10 mA, 50 mA and 100 mA, plasma polymerized films 
were formed on the surfaces of silicon wafers. 
The thicknesses of the plasma polymerized films were measured in the same 
manner as in Example 12, and also the films were analyzed by FT-IR 
according to the transmission method. The area of the absorption band in 
the region of 1450-1600 cm.sup.-1 inherent in benzene ring was measured. 
The relative values of the band areas in respective experiments were 
determined, taking the band area in the experiment in which continuous 
discharging was effected at a discharging current of 100 mA to be 1, and 
the relative values obtained were estimated as representing relatively the 
contents of benzene rings. The results are shown in Table 8. 
TABLE 8 
__________________________________________________________________________ 
Discharging conditions 
Discharging 
Voltage rise 
current under 
time for gas 
discharge 
Plasma polymerized film 
Discharging 
breakdown 
condition 
Content of 
Thickness 
system 
(msec.) (mA) benzene ring 
(.ANG.) 
__________________________________________________________________________ 
Example 46 
Pulse 12.5 
(20 KHz) 
100 8.2 3600 
Example 47 
" 16 (15 KHz) 
" 9.8 3400 
Example 48 
" 25 (10 KHz) 
" 3.5 3500 
Example 49 
" 50 (5 KHz) 
" 2.8 3800 
Comparative 
Continuous 
-- 10 1.5 1200 
Example 24 
Comparative 
" -- 50 1.2 3100 
Example 25 
Comparative 
" -- 100 1.0 4200 
Example 26 
__________________________________________________________________________ 
EXAMPLES 50-61 AND COMATIVE EXAMPLES 27-30 
Plasma polymerized films were formed in the same manner as in Examples 
46-49 except that allylamine, ethylenediamine, propylamine or aniline was 
used in place of styrene and the voltage rise time for gas breakdown was 
changed to 2 msec., 4 msec. or 8 msec. As Comparative Examples, plasma 
polymerized films were formed using plasma by continuous discharging. The 
thicknesses of the plasma polymerized films thus obtained were determined 
in the same manner as in Example 12, and the films were analyzed by FT-IR 
according to the transmission method in the same manner as in Example 12. 
The results are shown in Table 9. 
TABLE 9 
__________________________________________________________________________ 
Discharging conditions 
Plasma polymerized film 
Voltage rise 
Content Coefficient 
time for gas 
of of dynamic 
Organic Discharging 
breakdown 
amino 
Thickness 
friction 
compound system (msec.) 
group 
(.ANG.) 
(.mu.) 
__________________________________________________________________________ 
Example 50 
allylamine 
Pulse 2 6.2 5800 0.29 
Example 51 
" " 4 4.1 5600 0.28 
Example 52 
" " 8 1.3 5600 0.32 
Comparative 
" Continuous 
-- 1.0 6900 0.42 
Example 27 
Example 53 
Ethylenediamine 
Pulse 2 5.3 5500 0.30 
Example 54 
" " 4 4.8 5400 0.30 
Example 55 
" " 8 1.8 5800 0.35 
Comparative 
" Continuous 
-- 1.0 6800 0.47 
Example 28 
Example 56 
Propylamine 
Pulse 2 7.2 7100 0.26 
Example 57 
" " 4 6.8 6900 0.27 
Example 58 
" " 8 1.9 7500 0.33 
Comparative 
" Continuous 
-- 1.0 7900 0.45 
Example 29 
Example 59 
Aniline Pulse 2 6.9 6300 0.31 
Example 60 
" " 4 6.2 6200 0.30 
Example 61 
" " 8 1.4 6500 0.35 
Comparative 
" Continuous 
-- 1.0 7100 0.46 
Example 30 
__________________________________________________________________________ 
EXAMPLE 62 AND COMATIVE EXAMPLE 31 
Under the following conditions, according to the same procedure as in 
Example 12, a plasma polymerized film was formed on the surface of a 
silicon wafer (diameter 50 mm, thickness 300 .mu.m). 
Power source: AC power source (13.56 MHz), 
Organic compound: tetramethyltin (flow rate 10 ml (STP)/min.), 
Pressure: 50 mTorr, 
Time of discharge condition in pulse discharging: 10 msec., 
Time of non-discharge condition in pulse discharging: 40 msec., 
Voltage rise time for gas breakdown: 18 nsec., 
Current during the time of discharge condition: 100 mA, 
Polymerization time: 1 hr, 
Electron temperature during the time of discharge condition: 
2.7.times.10.sup.4 to 3.0.times.10.sup.4 K. 
As Comparative Examples, a plasma polymerized film was formed in the same 
manner as in the above example except for effecting continuous discharging 
in place of pulse discharging. 
In the case of pulse discharging, a thin film with a thickness of 6500 
.ANG. like a metal having luster was obtained, and it was found to be a 
film with a smooth surface by observing by a scanning type electron 
microscope (.times.10000). On the other hand, in case of continuous 
discharging, particles with sizes of 5000 to 7000 .ANG. were found to be 
dispersed on a thin film with a thickness of 1250 .ANG. which is yellowish 
and transparent without luster.