実験報告書様式（一般利用課題・成果公開利用）

MLF Experimental Report

提出日 Date of Report

課題番号 Project No.

装置責任者 Name of responsible person

2015A0105

山田悟史

実験課題名 Title of experiment

装置名 Name of Instrument/（BL No.）

Porosity Control of Porous Diamond-like Carbon Membranes

SOFIA / BL16

実験責任者名 Name of principal investigator

実施日 Date of Experiment

藤井 義久

2015/4/1– 2016/04/30

所属 Affiliation(国)物質・材料研究機構
試料、実験方法、利用の結果得られた主なデータ、考察、結論等を、記述して下さい。（適宜、図表添付のこと）
Please report your samples, experimental method and results, discussion and conclusions. Please add figures andtables for better explanation.
1. 試料 Name of sample(s) and chemical formula, or compositions including physical form.
Name of samples: porous diamond-like carbon (DLC)

petri dishcarbon membrane

Chemical formula: C x H y N z
pure water

Figure 1 shows the photo image of our porous diamond-like carbon(DLC) membrane floated on water.

Figure 1. DLC membrane floated on water.

2. 実験方法及び結果 （実験がうまくいかなかった場合、その理由を記述してください。）
Experimental method and results.

If you failed to conduct experiment as planned, please describe reasons.

Experimental method

Diamond-like carbon DLC membranes are prepared from various precursor gases onto thick silicon
blocks with a size of 40 mm × 40 mm × 7 mm by CVD method. The thickness of the membranes in adried state is controlled to be approximately 60 nm which is appropriate for NR measurements. To
evaluate the intrinsic swollen structures of these porous DLC, membranes are aged in deuterium oxide(D 2 O) for a given time, which is sufficiently enough to induce contrast change by sorption of deuteratedliquids. Density profiles of the films along the direction normal to the surface in contact with deuterated
liquids are examined by NR measurements. The neutron beams are guided into the film from the siliconside, and the reflected beam is detected under the specular condition.

12. 実験方法及び結果（つづき） Experimental method and results (continued)
Results(a)100

Figure 2(a, c) show the reflectivity curves as a function of the scattering

Reflectivity

vector (q = (4π/λ)sinθ, where λ and θ are the wave length and the incident

experimental
fitting curve

10-2

angles of the neutron beams, respectively) for porous DLC films in air (a)10-4and under deuterated water (c). The open symbols denote the experimental
data, and the solid curves were fit curves calculated from the scattering

10-60in panel (a) and (c) are in good agreement with the experimental data, it is(b) 5

most likely that the model (b/V) profiles drawn panel (b) and (d) in Figure 24(b/V)•104 / nm-2

Since the solid curves

length density (b/V) profiles in Figure 2(b) and (d).

would reflect the density profiles of the films. The (b/V) values for silicon(Si), and native oxide layer (SiO x ) were 2.07×10−4 and 4.10×10−4,
respectively. The fitting parameters are summarized in Table below. It is0.5

q / nm-1

1.0

1.5

native oxide layer

3DLC layer

Si21

noteworthy that the (b/V) value of the DLC film in water was higher than that0of the film in air, indicating that water molecules with higher (b/V) value

040
2060
Distance from surface / nm(c)deeply penetrated into the film. Then, the water content of the film wasexperimental
fitting curve

100
Reflectivitycalculated on the basis of (b/V) difference between DLC films measured in
air and under water. Surprisingly, the water content in the interior region,

10-2

namely, the constant density region, of the film was almost 50 vol %. Since

10-4

the porous film contained water molecules after being immersed in the water,
it became slightly thicker than before. However, the thickness increasing

10-6
0from 56.3 to 61.2 nm was only 9%. If the film is in fact swollen by water(b/V)•104 / nm-2

film. It is plausible to assume that above mentioned difference is originatedfrom the pore with sub-nanometer scale if we consider that our DLC film
contains the porous structure. Therefore, on the basis of neutron reflectivity
measurements, the initial volume fraction of the pore was estimated as almost

porous DLC films will be discussed in conjugated with above mentioned

20Air

in waterthickness / nm(b/V)•104 / nm-2

thickness / nm(b/V)•104 / nm-2

-0-

6.38

DLC

56.3

1.58

61.2

4.13

SiOx

7.45

4.10

7.45

4.10

Si-

2.07-

2.07

2040
2060
Distance from surface / nm

Figure 2. Neutron reflectivity for DLC filmin (a) air and (c) deuterated water. Opensymbols depict experimental data, and solidlines represent the reflectivity calculated on
the basis of the scattering length density(b/V) profiles, respectively.

Table. Parameters Used to Fit Obtained Reflectivity
in AirSwollen DLC layer

4results.

Curves

1.5
D2O

6using ellipsometry. The value of refractive index of our porous DLC film wasestimated the volume fraction of pores. The filtration properties of these1.0Si40 %. We also evaluated the refractive index of these porous DLC films by

In this experiments, we revealed the evidence of the existence of pores andq / nm-1(d) 8molecules, the thickness must be increased to conserve the mass of DLC

reasonable when we take into account the effects of sub-nanometer pores.

0.5