Operation Manual

LB device

KSV Minitrough

Revision 1.1
Table Of Contents

1. INTRODUCTION------------------------------------------------------------------------- 1

2. PHYSICAL DESCRIPTION----------------------------------------------------------- 2

2.1. Overview ------------------------------------------------------------------------------2

2.2. System 1 -------------------------------------------------------------------------------3

2.3. System 2 -------------------------------------------------------------------------------4

2.4. System 3 -------------------------------------------------------------------------------5

2.5. System 4 -------------------------------------------------------------------------------5

2.6. Mechanics-----------------------------------------------------------------------------6

2.7. Additional Devices ---------------------------------------------------------------- 10

2.8. Special Troughs-------------------------------------------------------------------- 11

3. PRELIMINARIES -----------------------------------------------------------------------15

3.1. Connections------------------------------------------------------------------------- 15

3.2. Cleaning ----------------------------------------------------------------------------- 16

3.3. Dipper Substrate Attachment -------------------------------------------------- 19

3.4. Monolayer Material Spreading ------------------------------------------------ 19

3.5. Experimental Setup--------------------------------------------------------------- 20

4. TECHNICAL SPECIFICATIONS---------------------------------------------------21

4.1. Deposition System----------------------------------------------------------------- 21

4.2. Film Pressure Measuring System---------------------------------------------- 21

4.3. Film Area Control System------------------------------------------------------- 21

4.4. Trough------------------------------------------------------------------------------- 22

4.5. General ------------------------------------------------------------------------------ 22

5. CONTACT INFORMATION----------------------------------------------------------23
1

1. Introduction

The Langmuir and Langmuir-Blodgett (LB) devices available from KSV

Instruments are efficient and effective in investigating the properties of floating

monolayers, precise deposition of multilayers onto solid substrates or simply

as platforms for use in observing surface chemistry effects such as the

breakdown of an enzyme or the crystalline structure of a surfactant. The wide

range of available systems and the many modules available make

customisation a charm, and if the troughs available do not suit your needs

then contact us about designing a particular trough to your specifications. There are four series of LB systems available today, the KSV 5000, 2000, Minitrough and the Minimicro in descending order of size. The differences

between the systems are mechanical, the same software and interface unit

operates all of the LB devices. KSV 2000 is the basic multipurpose LB device. KSV 5000 adds a sturdy frame with automatic elevator arms for attaching

additional measurement devices, becoming the most versatile LB device

available today. The KSV Minitrough is a more compact and economical LB

device. The KSV Minimicro is a small and elegant LB device brilliant for

depositions on small substrates or to minimise sample volumes. This is the device-specific manual for the KSV Minitrough LB device, featuring

details such as physical descriptions and cleaning instructions. Please see the

LB installation manual or the LB software manual for details on installation, calibration, measurement taking or data analysis.
2

2. Physical Description

2.1. Overview

The general physical layout of the KSV Minitrough Langmuir-Blodgett (LB)

system consists of the trough with the subphase and the surfactant, barriers

which can adjust the surface pressure by reducing the area available to the

surfactant, a balance with a Wilhelmy plate which monitors the surface

pressure and an interface unit to control the devices and communicate with

the computer running the experiment. The available systems are modular, based on System 1. System Trough Devices Available experiments

1 Flat Balance Langmuir film balance

2 Flat with well

Balance

and

dipper

Multilayer LB-films on solid

substrate and Langmuir film

balance

3 Flat with quartz

window

Balance

Langmuir film balance for

Microscopy experiments

4 Flat with extended

range

Balance Langmuir film balance
3

2.2. System 1

The appearance of the instrument depends on the system in use. System 1 is

the most basic setup, consisting of a balance and a trough with a barrier drive

system.

Image 2.1: KSV Minitrough System 1. 1) Balance

2) Trough

3) Barriers

4) LayerBuilder

System 1 is designed for the study of floating monolayers. PTFE trough with a surface area of 273 cm

2

, (L364 x W75 x D7 mm

3

) and a

subphase volume of 190 ml.

1

2

3

4
4

2.3. System 2

The System 2 additions over System 1 are the dipper, a second stand for the

dipper and a trough with a well.

Image 2.2: KSV Minitrough System 2. 1) Balance

2) Trough

3) Barriers

4) LayerBuilder

5) Dipper

6) Well

System 2 is designed for the study of floating monolayers and for the

deposition of multilayer films of one substance on a solid substrate. PTFE trough with a surface area of 273 cm

2

, (L364 x W75 x D7 mm

3

), a

dipping well (L37 x W37 x D64 mm

3

) and a subphase volume of 280 ml.

2

3

4

5

6
5

2.4. System 3

In addition to system 1 the trough is fitted with a quartz window. System 3 is

designed for the microscopic study of monolayers and floating monolayers. It

is suitable for all conventional microscopes and inverted fluorescence

microscopes.

Image 2.3: KSV Minitrough System 2. 2.5. System 4

In addition to system 1 the trough length is doubled. The dimensions of the

trough are surface area of 587 cm

2

, (L782 x W75 x D7 mm

3

) and a subphase

volume of 290 ml.
6

2.6. Mechanics

A) Computer

The computer controls all functions of the instrument. Because each device

includes its own microprocessor, the computer sends only high level

commands to them (for instance "Move with certain speed" or "Go to certain

position" and so on). All devices are listening to every message, but they

become active only when they recognise their own address. The computer should be a PC running Windows 2000/XP/Vista. A 1GHz

processor and 512MB RAM memory are recommended. B) Barrier Driving System

The barrier position is controlled by a micro step driven stepping motor. The

motor moves the barrier holder using a tooth belt. The holder itself is attached

to a linear motion system, which is equipped with ball bearings. The barrier driving system is equipped with adjustable safety switches which

stop the barrier immediately when the barrier holder hits the switches. The

position of the barrier is measured using an optical encoder. The position is

relative and so a zero point at a known position must be set manually. The control electronics are located inside of the barrier driving unit. There is a

15-pin connector on the rear of the unit. The barrier driving unit should be

connected to the Interface unit through this connector.
7

Image 2.4: Block diagram of the barrier driving system

C) Surface Balance

The surface pressure is measured by using the Wilhelmy plate method (round

rod optional). The Wilhelmy plate is a carefully sandblasted platinum plate or a

clean paper plate, which is put partly under the surface of the subphase. Normal practice is to position the plate so that one third of it is under the

subphase. The force acting on the plate depends on surface pressure. This

force is measured using the electro-balance. The total measurement range of

the balance is +/- 2000 mg. The width of the platinum Wilhelmy plate has

been chosen so that 1 mN/m corresponds to 4 mg. For paper Wilhelmy plates

this value is commonly about half as great as with the platinum plates.
8

Image 2.5: Block diagram of the surface balance. D) Deposition system

The deposition system is DC motor controlled to ensure vibration-free

operation. The speed range of the dipping arm is 0.1...85 mm/min and

maximum stroke is about 75 mm. The DC motor is servo controlled to keep

the speed constant. The position is determined with an optical encoder. The

deposition system is equipped with safety switches which stop the motor

automatically in both ends.
9

Image 2.6: Block diagram of the deposition system. E) Trough and Barriers

The troughs are made of a solid piece of PTFE. The trough is glued onto an

aluminium base plate, in which there are water channels for the thermostation

of the subphase. The temperature is adjusted with a water bath circulator, which is connected to the trough with special connectors. These connectors

include valves in both parts, so the connection can be opened without any

leakage. The maximum temperature allowed is 60C!

The barriers are made out of hydrophilic material, which ensures that the film

does not escape the barrier. The barrier material is polyacetal (Delrin) and it

should be noted that Delrin is not resistant to acids or chloroform, so do

not use these as cleaning agents. Chlorinated solvents such as these can

still be used as spreading solvents. The barrier is equipped with a round rod, which fits into the barrier holder.
10

2.7. Additional Devices

Various additional devices can be used to improve measurement conditions, enable additional measurement methods or to provide additional data. A) Thermostation

The temperature of the subphase can be monitored with a temperature probe

that connects directly to the Interface Unit. The temperature sensor is covered

with a thin PTFE tube and it can be attached to the trough with a special

holder. The display units are in degrees Celcius, though Fahrenheit is

available on request. This keeps a full record of the temperature conditions of the experiment, but to

adjust that temperature a water bath is required. KSV troughs have built-in

piping in the aluminum block which holds the teflon trough. Connect the water

bath to the ports along one end of the trough. KSV Instruments recommends

the Julabo water bath also available from KSV, though others can be used as

well. Connect the water bath to an available COM port on the computer. Use the

software's Manual Control Unit to adjust the temperature settings for the water

bath. B) pH Probe

The acidity of the subphase can be monitored with a pH probe that connects

directly to the LayerBuilder interface unit. C) Stirrer

A magnetic stirrer consists of a rotating magnetic field source and a small

magnetic bar. The rate of rotations can be adjusted with the control knob on

the power supply. A magnetic stirrer is used particularly with enzyme reaction

studies. D) Minicab Cabinet

A cabinet that can be placed around the LB device to isolate it more from the

environment. Includes appropriate holes for water bath circulator tubes and

cables. E) Horizontal Dipping Clamp

The standard dipper clamp can be replaced by a horizontal dipping clamp for

the purpose of conducting Langmuir-Schaefer experiments. The two dipping
11

clamps can be interchanged quickly and easily, and no software upgrade is

necessary. Set the zero position of the dipper as the level at which the plate is

wetted first. With longer experiments the dipping depth might need to be

increased over time to reach the surface due to evaporation. F) Surface Potential Probe SPOT

A surface potential probe (KSV SPOT) is a tool for measuring the surface

potential of an interface or a solid. KSV SPOT uses the vibrating plate

capacitor method. G) Brewster Angle Microscopy BAM

Brewster angle microscopy (BAM) provides visual information of two

dimensional structures in monolayer films. It utilises a laser and a CCD

camera to obtain images at 25 fps. H) Interfacial Shear Rheometer ISR

The ISR 400 provides information on the shear stress of interfaces, particularly useful for low viscosity applications. A teflon-coated magnetic

needle rests at the interface, and as a magnetic field is induced the movement

of the needle is observed with a microscope. 2.8. Special Troughs

The choice of trough is one of the most important ones to make when

acquiring and using a LB device. Several troughs are available designed, and

many more can be manufactured according to specifications. The specialized

trough types available at the moment are alternate dipping, conductivity, compartmentalised, enzyme reaction, oil/water interface and surface potential

troughs. Additionally several features can be incorporated into most of the

troughs, these are an injection port, a quartz window and low subphase

volume. A) Low Volume Trough

The low volume trough requires smaller subphase and sample volumes. Effective surface area is 136 cm

2

(L316 x W50 x D1) and subphase volume is

18ml. B) Conductivity Trough

The conductivity trough is used to measure the conductivity of the monolayer. Four electrodes are placed near the center of the trough, two on each side of

a central rise. The central rise divides the trough into two compartments with a
12

narrow band of glass connecting the subphases of the different

compartments.

Image 2.7: The conductivity trough

The exterior electrodes introduce a current and the interior electrodes

measure the potential between them. The subphase volume through which

the current can flow is minimized with the use of the glass band. C) Enzyme Reaction Trough

The enzyme zero order breakdown reaction can be observed with this special

trough. The center compartment is connected to the outer compartments with

glass bridges allowing the pressures to be adjusted without disturbing the

center compartment.

Image 2.8: The enzyme reaction observation trough. The enzyme is placed in the centre trough and the initial surface pressure is

measured. A protein is placed through an injection port and as the protein

interacts with the monolayer the amount of monolayer material decreases and

surface pressure decreases. The barriers approach the centre to keep the

surface pressure (and thus mean molecular area) constant, and the area

removed by them can be used to calculate the activity of the enzyme.
13

A stirrer might be necessary to properly observe the activity of the enzyme. D) Oil/Water Interface

The oil/water interface trough places the monolayer material between two

liquids as opposed to between a liquid and a gas. The denser liquid, usually

water or another polar liquid, is poured into the trough up to the first notch. The monolayer is placed onto the surface of the polar liquid. The organic

liquid is then poured gently on top of the water so that the holes in the barriers

are distinctly above the interface but covered by the oil. When the barriers are

brought closer together the monolayer material is compressed.

Image 2.9: The oil/water interface trough

Alternatively the monolayer material can be mixed into the oil and as the oil is

poured the monolayer material forms a monolayer at the interface due to the

strong polar attractions between the polar subphase and the hydrophilic end

of the monolayer material. E) Additional Trough Features

 A quartz window can be added to most troughs to enable live

observation with a microscope or similar optical instrument.  An injection port can be used to add a substance into the trough after

the beginning of an experiment. As it is important not to disrupt the

surface the injection port leads a needle tip from the side of the trough

to the subphase. It is a standard feature with enzyme reaction troughs.  A low subphase volume trough reduces the area that is available for

the subphase, thus reducing the amounts of materials required.
14

F) Custom Troughs

Many situations arise where a custom designed trough is necessary to

accomplish a particular task. KSV Instruments supplies many custom

designed troughs, be they extensions of current designs or completely new

concepts. Ask us for more information about a trough that suits your needs!

Image 2.10: Some past custom-made troughs.
15

3. Preliminaries

3.1. Connections

Check that all devices are attached to the LayerBuilder interface unit. Check

that the power cable is connected to the interface unit and that it is turned on. Turn on the computer and start the sgserver for LB systems. It can be located

from the Start menu under Programs > LB. Open the Manual Control Unit

by clicking on the menu Control Panel. Open the Barrier1 tab.

Image 3.1: The Manual Control Unit used to control attached devices. Check that the safety limit switches are properly set by first closing and then

opening the barriers. Adjust the positions of the switches if necessary.
16

3.2. Cleaning

Before an experiment the trough and barriers must be cleaned. Use rubber

gloves to minimise oils from the skin contaminating the apparatus. The

importance of cleanliness cannot be overstated!

The troughs used by KSV can be removed from the frame and carried to a

sink for ease of cleaning. A recommended cleaning procedure is to first brush

with a soft brush covered in ethanol or another organic solvent (mechanical

and chemical cleaning) and then rinse with ion exchanged water. Take care

not to scratch the surface!

Images 3.2 and 3.3: Brushing the trough with ethanol (left) and rinsing the

barrier with pure water.

If the trough has not been used for a longer period of time then first washing

with hot water and a commercial detergent might be appropriate before

performing the standard cleaning described above. Replace the trough in the

frame, checking that the screws fit into the available notches.
17

Image 3.4: Replacing the trough so that the screws slot into the respective

notches. Clean the barriers. The appropriate cleaning method is the same as with the

trough. When one barrier is cleaned place it on top of the trough before

cleaning the other barrier. Take special care in choosing the appropriate

handhold on the barrier so that replacing it will be simple, avoid touching the

delrin itself!

Rinse the aspirator tip with ethanol and ion exchanged water. On the Manual Control Unit click Open and wait until the barriers are in the

desired position, most often fully open. Press Zero. Fill the trough with the

subphase. In most cases pure water will be a good choice. Pour the water

gently on to the trough so that the level of the water rises distinctly (at least

3mm) above the level of the trough. Turn on the aspirator and click on Close to start bringing the barriers together. Contaminants on the surface of the water will be picked up by the barrier. Run

the tip of the aspirator along both barriers several times. The purpose of this is

to remove contaminants and not to suck too much of the water so run the tip

over the surface rather than plunging it into the water. When the barriers are

fully closed run the aspirator tip over the surface between the barriers several

times to pick up remaining contaminants. A systematic pattern such as three

vertical and horizontal lines (#) is recommended. Remove enough water to lower the water surface until it is level with the

trough.
18

Image 3.5: Sucking contaminants from the barriers. Clean the Wilhelmy plate. A thorough cleaning entails heating the platinum

Wilhelmy plate over a flame (such as a Bunsen burner). Heat the plate over a

blue flame hot enough to make the plate glow red in just a few seconds, a

flame that is too cool will leave residues on the plate surface. Alternatively

rinsing with ethanol and ion exchanged water should be enough for most

cases of frequent use. Once the experiment is finished the Wilhelmy plate

should be stored in a water-soluble organic solvent such as ethanol. Attention! The platinum Wilhelmy plate is an excellent catalyst for the

combustion of methanol! Beware of operating the Wilhelmy plate around

methanol, especially when hot. After the plate is completely glowing remove it from the flame and hold it for

several seconds to allow it to cool. Dip the plate into the water in the trough

and hang it from the balance hook. Set the plate so that about two thirds of it

is covered and it is perpendicular to the barriers. For information on using a paper Wilhelmy plate, please see the LB software

manual. Open the barriers. In the Manual Control Unit open the Balance tab and

press Zero Balance1. The reading is now zeroed with pure water, and the

measured difference in surface tension will be the surface pressure. Close the

barriers. Pure water does not cause the surface pressure to change, so any

change in surface pressure is caused by contaminants. If the surface pressure

does not exceed 0.2mN/m the water can be considered sufficiently clean.
19

3.3. Dipper Substrate Attachment

If about to perform a Dipping Experiment with a hydrophilic substrate then

clean the sample as appropriate. In the Manual Control Unit open the

Dipper1 tab and press Up and wait until the dipper arm moves well above the

surface. Attach the substrate to the dipper arm and make sure that the

substrate is still above the water surface. Take care not to touch the surface!

Lower the substrate slowly from the Manual Control Unit and at when the

water touches the substrate press Stop and then Zero. Then lower the

substrate as far as it is meant to go for the experiment.

Images 3.6 and 3.7: Attaching a substrate to the dipper (left) and zeroing the

position of the substrate for a dipping experiment. 3.4. Monolayer Material Spreading

Fill a precision syringe with a suitable volume of a prepared solution of

monolayer material and a volatile organic solvent. The organic solvent should

be non-polar so that it will not mix with the water and volatile so that it will

evaporate from the surface, for example chloroform or hexane. A

concentration of 1 mg/ml is usually a good choice to start investigations with. Placing the solvent on the water should be done with care, gently push on the

syringe to get a drop out of the needle and then touch the surface with the tip

of the needle. Do not let the drop fall from the needle as some of the sample

might be lost to the subphase as micelles and the surfactant does not spread

evenly! Furthermore the waves caused by drops can carry monolayer

materials to the edges of the trough.
20

Image 3.8: Place the sample onto the water with care. Wait 10-15min for the solvent to evaporate. Use this time to fill in the

Experimental Setup for this experiment. Press on the appropriate icon to

start a new experiment, this will first open the Experimental Setup. Double- check that the dimensions of the trough are correct as this plays an important

part in the analysis of the obtained data. 3.5. Experimental Setup

The Experimental Setup is used to identify the appropriate procedure and as

a record for later analysis. Access this screen by beginning a new isotherm, dipping or alternative trough dipping experiment. Fill in all of the relevant

sections. To add items to the drop-down menus use the Edit Database

function. For more details please see the LB Software Manual.
21

4. Technical Specifications

4.1. Deposition System

Control and operation Software controlled unsupervised

and automatic film deposition. User defined deposition

parameters. Deposition speed 0.1 to 85 mm/min

Speed adjust Increment 0.1 mm

Optional speed range 0.2 to 170 mm/min

Deposition cycles 1 to unlimited consecutive

depositions

Dwell times 0 to unlimited seconds, individual

adjustment for upper and lower

end point of substrate

movement. Deposition arm 75 mm max. stroke

Max. size of substrate 60 x 35 mm

Type of motor Servo controlled DC motor

4.2. Film Pressure Measuring System

Measuring principle Wilhelmy plate, platinum or paper

sensor element or round rod

connected to micro-electronic

feedback system for surface

pressure control. Software

controlled operation, user defined

measuring parameters. A floating

barrier sensor element with the

same features as above also

available. Dynamic range 0 to 250 mN/m

Resolution 4 μN/m

4.3. Film Area Control System

Surface area regulation Two symmetrically moving surface

barriers. Software controlled

operation and user defined process

parameters.
22

Surface barrier Leak proof hydrophilic (Delrin)

barriers. Hydrophobic (Teflon)

barriers by request or optional. Barrier speed 0.01 mm to 400 mm/min (max. relative speed 800 mm/min)

Barrier motor High precision micro step driven

stepper motor. Accuracy Greater than 99%

4.4. Trough

Dimensions Systems 1 and 3: surface area 273

cm

2

, (L364 x W75 x D7 mm

3

), subphase volume 190 ml. System 2: surface area 273 cm

2

, (L364 x W75 x D7 mm

3

), dippin well

(L37 x W37 x D64 mm

3

), subphase

volume of 280 ml. System 4: surface area 587 cm

2

, (L782 x W75 x D7 mm

3

), subphase

volume of 290 ml. Trough material Solid PTFE (Teflon), 1.5 mm

bottom thickness, mounted on a

thermo regulated base plate. Barrier material Hydrophilic Delrin (polyacetal). Delrin is not suitable to be

washed with acids or

chloroform. Teflon barriers can be provided as

option. Temperature range 0 to +60 C

4.5. General

Environmental protection Optional vibration isolated bases

and laminar flow hoods available. Computer requirements PC with a 1 Ghz processor and

512 MB memory running

Windows

TM

2000/XP/Vista. Voltage

Nominal 220 V, 50/60 Hz 110 V, 50/60 Hz

Operational 176-264 V, 40/440 Hz 90-132 V, 40/440 Hz
23

5. Contact Information

If any problems arise please feel free to contact a local distributor or KSV

Instruments directly. KSV Instruments can be contacted from this address:

KSV Instruments Ltd. Hˆyl‰‰mˆtie 7

FIN-00380 Helsinki

Finland

Tel. +358-(0)9-5497 3300

Fax +358-(0)9-5497 3333

E-mail info@ksvltd.fi for sales and

support@ksvltd.fi for service or technical questions

http://www.ksvltd.com

Local distributors are listed at our website, www.ksvltd.com.