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KSV 5000 LB-system
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KSV 5000 System is a modular Langmuir trough system which expands from a
conventional film balance to a high performance Langmuir-Blodgett instrument or
to a fully equipped alternating multilayer Langmuir-Blodgett system.
The heart of the system is the mainframe module and the system set-up is
built around it by using the modules and accessories. All the modules are easily
plugged into the mainframe and the system set-up is factory installed and ready
to use. The configuration can be up-graded later with various accessories and
modules.
KSV 5000 System is available in three basic modular set-ups.
System 1 Langmuir Film Balance for conventional
Langmuir film studies
System 2 Langmuir-Blodgett instrument for
deposition of Langmuir-Blodgett films
System 3 Alternating multilayer Langmuir-Blodgett
trough for fabrication of films consisting of two molecular materials
Specifications
KSV 5000 System 1
Langmuir film balance for conventional monolayer analyses and Langmuir-Film
experiments. Biomembrane and enzyme kinetic reaction studies. Upgradable to
System 2 and 3.
Module configuration:
- Mainframe
- Film balance
- Symmetric compression trough
| Film balance measuring range |
0 to 125 mN/m |
| Film balance resolution |
4 µN/m |
| Trough surface area |
864 cm2, 576 x 150 mm |
| Subphase volume |
0.75 l |
| Subphase thermostation |
0-60 C |
| Compression speed |
0.01 to 800 mm/min |
KSV 5000 System 2
Langmuir-Blodgett instrument for unsupervised deposition of ordered
multilayer LB-films and for KSV 5000 System 1 applications. Upgradable to System
3.
Module configuration:
- Mainframe
- Film balance system
- Film deposition system
- Symmetric compression trough with dipping well
| Deposition speed |
1 to 85 mm/min. or 2 to 170 mm/min. |
| Speed adjustment |
in 0.1 mm/min. increments |
| Deposition cycles |
unlimited |
| Delay times |
adjustable from 1 to 9999 sec. |
| Dipper motor |
servo controlled DC motor |
| Trough area |
864 cm2, 576x150 mm |
| Trough volume |
0.95 l |
| Subphase thermostation |
0-60 C |
| Substrate size |
max. 100x100 mm |
| Length of dipper stroke |
145 mm |
| Film balance measuring range |
0 to 125 mN/m |
| Film balance resolution |
4 µN/m |
| Compression speed |
0.01 to 800 mm/min |
KSV 5000 System 3
Alternate Multilayer Layer Langmuir-Blodgett system for unsupervised deposition
of ordered layers of two different monolayer molecules and System 1 and System 2
applications.
Module configuration:
- Mainframe
- Alternate layer module
| Deposition speed |
1 to 85 mm/min. or 2 to 170 mm/min. |
| Speed adjustment |
in 0.1 mm/min. increments |
| Deposition cycles |
unlimited |
| Delay times |
adjustable from 1 to 9999 sec. |
| Dipper motor |
servo controlled DC motors |
| Trough area |
2x 960 cm2, 800x120 mm |
| Trough volume |
5.5 l |
| Subphase thermostation |
0-60 C |
| Substrate size |
max. 100x100 mm |
| Length of dipper stroke |
145 mm |
| Film balance resolution |
4 µN/m |
| Compression speed |
0.01 to 800 mm/min |
| Physical dimensions |
system 1 |
system 2 |
system 3 |
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| Height |
72cm |
72cm |
72cm |
| Length |
112cm |
112cm |
112cm |
| Depth |
60cm |
60cm |
69cm |
| Weight |
35kg |
37kg |
55kg |
| Operating voltage |
90-132 V or176-264 V, 50/60 Hz |
Catalogue summary
Symmetric compression
KSV uses symmetric compression of the monolayer in all of its troughs. Symmetric
compression, achieved by enclosing the monolayer in between two moving barriers,
produces uniform shear through out the whole film area minimising possible
parabolic film flow effects. The accuracy and reproducibility of the film
pressure measurement with the Wilhelmy Plate is increased because the plate is
evenly compressed from both sides. No floating of the plate with the flow will
occur, even with stiffest of films.
With simple arrangement the barriers can be modified to move in the same
direction, for example to go over various subphases in biological applications.
Film deposition
The key issue in successful film deposition is to maintain monolayer molecular
orientation unchanged during the transfer from air/water interface onto a solid
substrates. The parabolic film flow effect, center moving faster than sides,
caused by the friction between the side walls and the film is the major source
for orientation changes during the deposition. This problem comes evident
especially with conventional single barrier and band type of systems where
monolayer flows to one direction only. These systems produces another
problem in connection of substrate deposition. Since the face of the substrate
will be against the film flow there will be significant back drag on the
opposite side of the substrate causing localized orientation changes.
Consequently the pressure measurement, when performed near the deposition or at
back of substrate will become unreliable because of the local instabilities.
The symmetric compression avoids the back drag phenomena and pressure
measurement problems during the deposition process. The film deposition is
performed right at the film compression center where the film reaches its
highest degree of orientation. Orientation changes during deposition will not
occur since film compression is uniform.
The dipper is equipped with high precision DC motor to ensure smoothest possible
movement of the dipper shaft. The speed of the shaft, the number of deposition
cycles, dwell times, partial depositions etc. all are user programmable and
operation controlled by the software. The substrates can be dipped perpendicular
or parallel to the barrier movement.
Depositing alternating multilayer films
The unique substrate transport system of the KSV 5000 System 3 with a clean
subphase in the middle of the two trough compartments makes it possible to
deposit the alternating LB-layers in any desired stacking order.
The Film Deposition System, the dipper, is capable of depositing alternating
LB-films of x, z, y or any other type fully automatically, continuously and
without cross contamination. Stacking order of the layers is dependent only on
the chemistry of the molecules not on the instrument hardware.
The dipper consist of two independent arms equipped with automatic clamps to
hold the substrate. Rotation of the dipper, vertical movement of its arms and
opening and closing of the clamps is all software controlled. The upper arm is
for airborne travel and the lower arm for under subphase travel of the
substrate. There is no cross contamination as only the substrate penetrates the
film and not the mechanics moving it.
The trough, made of form sintered solid PTFE, consist of two rectangular shape
compartments each having its own symmetric compression system and film balance.
Both compartments function independent from the other.
Film compression, pressure monitoring and deposition processes for each
compartment is controlled by a KSV Multitasking software.
Software
KSV 5000 is run by a multitasking software allowing creation of complex
measurement sequences without software modifications. Software includes ready
written and menu driven programmes covering most of known LB-film experiments.
No reprogramming is needed and the user is directed trough the set up programs
step by step.
Standard programs include:
- Compression/relaxations isotherms - vs mma, vs time or vs any desired
measurable factor
- Transfer ratio and deposition profiles
- Analysis of enzyme kinetics and enzyme penetration
- Analysis of hydrolysis of monolayers
- Isochores and isobars
- Constant increase/decrease of vs mma, vs time or vs any desired measurable
factor
The software is a complete program development environment including its own
programming language, the Experiment Programming Language, EPL. With EPL you can
write your own test protocols to perform specific measurements. For example you
can design a command string to increase/decrease surface pressure following
linear or non-linear progression from given start point to endpoint of the
experiment and during which depositions of film is performed at given time
intervals or at give surface pressures.
The program continuously commands and receives data from all devices hooked
to the system (dipper, barriers, film balance, temperature, pH, surface
potential etc.) and stores it automatically on the hard disk. Up to four Y-axes
can be selected as function of X-axis. The process of the experiment can be
monitored in real time on the screen. As all the experimental data is stored it
is possible with the help of Analysis Program to call out desired data of an
specific experiment and have the graphs refitted to Y and X axes.
The soft ware is written in C language in order to have full control of the
computer .
Trough geometry
The wide variety of LB-film applications requires flexibility in the geometrical
design of the trough. Very often special shapes and sizes are needed. The use
original rectangular Langmuir trough with moving barriers offers greatest
flexibility in geometrical design of the troughs. In band and moving wall types
of systems the band defines the trough shape while acting as a barrier. In such
a systems the trough geometry is fixed and can't be changed.
Customised and standard troughs
The size of the bottom PTFE block of the KSV's troughs is standardised making it
possible to manufacture nearly shape or size troughs. No matter whether deep or
shallow, long and narrow or short and wide all shapes can be easily made and
without any extra cost.
Cleaning and dismantling
Easy access to troughs and barriers, their quick dismantling and cleaning plays
vital role in every day use of LB-trough. KSV's troughs are independent modules
from the main instrument body and can they be dismantled simply by lifting by
hand. The instrument body has a special guide rail for snap-in mounting of the
trough. The barriers are conveniently and accurately placed to their original
positions in their riders. All sharp angles are rounded for thorough cleaning.
Subphase temperature control
The temperature regulation and maintenance of accurate constant subphase
temperature is of one of the fundamental preconditions for successful film
fabrication. The smaller is the subphase volume the more accurate and fast is
its temperature regulation. The KSV PTFE trough with bottom thickness of approx.
1,0 mm is cemented on an aluminium heat plate. Aluminium, being a good
conductor, distributes energy evenly throughout the whole bottom area while
responding fast and accurately to the temperature changes. The walls of the
dipping well are also thermostated to minimise the temperature difference in
between the well and the rest of the trough bottom area.
Subphase water temperature is regulated by running thermostated water from an
external circulator through the heat plate. The temperature sensor probe,
situated in the subphase, constantly monitors subphase temperature while
commanding the external circulator.
Trough material
A pure solid PTFE (polytetrafluoroethylene) is used in all KSV's troughs mainly
because it is inert and highly hydrophobic and easy to clean. All troughs are
made of solid block of from sintered PTFE.
Sprayed PTFE coating is not used due to its porousness, impurities caused by
spraying process and because it can't be repaired in case of scratches.
Leak proof barriers
Often it is thought that in order to make good seal in between the PTFE trough
and barriers it is necessary to overfill the trough. Doing so usually caused
overspilling of subphase or film leakage over the trough edges.
KSV avoids these problems by a hydrophilic barrier material. Advantage are quite
obvious especially when experimenting high surface pressures.
To prevent film leakage over the edges surface level of the subphase should be
kept as low as possible. With low surface pressures this causes no problems
either with hydrophilic or hydrophobic surface barriers.
Special troughs
Enzyme kinetics trough
A zero-order trough was originally developed by Prof. Verger de Haas for
studying enzyme reactions in monomolecular films. It offers the advantage of
linear (zero-order) enzyme kinetics, and possibility of using mixed lipid
monolayers of constant composition as substrates for lipolytic enzymes.
The zero-order trough consists of a reaction compartment and a reservoir
compartment separated with a glass bridge just underneath the water surface. The
bridge prevents mixing of the subphases of the two compartments.
The enzymes or molecules are injected into the subphase of the reaction
compartment. The adsorbed molecules increase the surface pressure of the
monolayer and if the pressure is being kept constant by moving the barrier the
rate of the adsorption and the number of molecules adsorbed can be calculated.
Conductivity trough
The conductivity trough facilitates the measurement of the lateral
conductivities of monolayer films on water. Due to the glass bridge the
electrical resistance between the electrodes is increased to the extent where
one can easily measure films with conductivity better than one S/cm.
Conductivity measurements are performed under CO2 free atmosphere and highly
purified water is used.
Microscopy trough
Using mixed monolayers with fluorescent dyes one can observe the possible phase
separation of the different substances through the quartz window on the bottom
of the trough.
The trough is standard KSV trough with out dipping well. Quartz optical window
is fixed into the bottom of the trough. Optics of the microscope are arranged
below the trough and the monolayer is observed vertically beneath the trough.
Surface potential measurement trough
The surface potential of floating monolayer can be measured with KSV 5000SP
module and KSV surface potential measurement trough. The trough is designed long
and narrow in order to have maximum compression area. It is important to have as
much space as possible to compress the monolayer because the surface potential
of water/monolayer/air interface usually begins to change when the area/molecule
in the film is still quite large.
Online display
Digital display card displays on line status of desired parameter during an
experiment, e.g. surface pressure, dipping speed, barrier speed, etc. or any
other parameter selected by the user. standard mainframe includes two displays
cards one for barrier position and one for film pressure. Additional cards can
be ordered separately.
AD/DA converter cards
AD/DA converter cards are provided to measure signals from devices designed by
user. data is collected by the software.
Motorised height elevators
The motorised height elevator provide vertical movement for the film balance
head, dipper head, surface potential meter or any other measuring device. The
elevator is supported by Mainframe and the measuring unit it attached to the
elevator arm for accurate positioning. The vertical movement of the elevator is
controlled by manual key pad. The wetting procedures of the Wilhelmy Plate,
coarse drive of the dipper head to start position as well as manual control
drive of barriers are conveniently controlled from the remote control key pad.
The remote control of these key procedures reduces human activity above the film
area thus minimising contamination risk.
Film balance
Accurate measurement of the surface pressure and precise surface area control
system are crucial in fabrication of reproducible and defect free films. The
film balance is interfaced to a barrier driving system with a feedback circuit
for compression, expansion or for constant surface pressure operation modes. The
film balance uses Wilhelmy Plate method to measure the surface pressure. This
method incorporates a electronic micro balance and Wilhelmy Plate made of
platinum. Platinum is used because of its inertness and good hydrophilic
properties achieved by sand blasting of its surface. Platinum plate is easily
cleaned and durable in use. Only occasional calibration is needed and the
balance is electronically zeroed through the software.
Surface area control
The method of film compression is important in fabrication of reproducible
high quality films. Several designs have been developed in search of ideal film
compression. In these designs (bands, circular troughs and moving wall) the
attempt to eliminate one specific problem have often lead to limitation of
instruments versatility and reliability.
KSV uses original well proven Langmuir trough design improved with
symmetrical compression of the monolayer. This straight forward method have
proven itself to be most practical with out compromising the high standard of
your research work.
The compression method is only as good as the mechanics moving it. The power
of micro stepping motor is transmitted through a reduction gear box into a
precision tooth belt driving the barrier holders. The barrier holders rides on a
precision linear motion rail giving the barriers smooth and friction free
movement. The barriers are attached to their holders by hand for easy removal.
Moving wall compression, usable film area determined by width
of substrate, moving wall scratches sides of substrate, no dipping of circular
substrates.
Band compression, band pushed outwards by film pressure, film
collapse near corner post with condensed films, complex vibration causing
mechanics.
Circular trough, unstable pressure measurement due to uneven
pressure distribution caused by the difference of film speed at inner and outer
trough perimeter.
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