kulim Kht Sigma 701 Single Fiber measurements

Modified pore-flow model for pervaporation mass transport in PVDF hollow
fiber membranes for ethanol–water separation
2010
Panu Sukitpaneenit a , Tai-Shung Chung a,* , Lan Ying Jiang b
a Department of Chemical & Biomolecular Engineering, National University of Singapore, 10 Kent Ridge
Crescent 4 Engineering Drive 4, Singapore 117576, Singapore, b School of Metallurgical Science and
Engineering, Central South University, Changsha 410083, Hunan, PR China
For the first time, the mass transport phenomenon in pervaporation of the ethanol/water system via PVDF asymmetric hollow
fiber membranes has been demonstrated through the pore-flow model and a newly modified pore-flow model has been
proposed. The modified pore-flow model differs from the pore-flow model by factoring in the contribution of Knudsen flow to
vapor transport, which was ignored by the pore-flow model. The correlation of transport parameters to membrane pore size is
explored and it is found that the pore size expansion (including the change of membrane surface morphology) is strongly
dependent on the solvent in contact. The modified pore-flow model shows a better prediction for the permeate composition
than the pore-flow model and both models exhibit an excellent prediction of total permeate mass flux. The significance of
Knudsen flow contribution in vapor-phase transport as stated in the modified pore-flow model is discussed from the
experimental and theoretical aspects.
Journal of Membrane Science, Volume 362, Issues 1-2, 15 October 2010, Pages 393-406
Instrument(s) used:

Force tensiometers > Sigma 701

Kulim KHT Surface Tension Measurement. Sigma 702

Due to the unbalance of forces at the surface/interface the structure and composition of the surface/interface is different than in the bulk. Interactions at surfaces/interfaces therefore result in special orientations of molecules, accumulation of certain types of molecules at the interface, separation of positive and negative charges. This often results in a situation where the surface/interface properties are completely different from the properties of the bulk material. The knowledge of the properties of the outermost layer of a material is therefore very important in many cases.

Combined analysis of g and q gives information about the properties of the outermost layer of a surface in a simple way.

Kulim Theta QC-Portable Contact Angle Meter

YOUR PORTABLE CONTACT ANGLE METER FOR QUALITY CONTROL MEASUREMENTS OF:
- SURFACES AND COATINGS
- SURFACE TREATMENTS
- WETTABILITY
- ADHESION

Theta QC Optical Tensiometer is a mobile contact angle meter enabling characterization of solid surfaces and liquid-solid interactions. It is primarily used for quality control measurements and characterization of large objects

Theta QC deposits droplets from its integrated dispensing syringe which can be easily filled with your desired liquid. The drop can be visualized from the Viewfinder for accurate placement of the drop onto the solid sample.Theta QC Optical Tensiometer can be used in virtually any industry where surfaces and interfaces have a role to play. Please find below some of the main areas where optical tensiometry is used for quality control:

Theta QC working principle

Theta QC deposits droplets from its integrated dispensing syringe which can be easily filled with your desired liquid.
The drop can be visualized from the Viewfinder for accurate placement of the drop onto the solid sample.




Following deposition, a picture of the drop is taken. It is possible to set a delay between the drop deposition and the recording.

Theta QC analyzes the drop shape and calculates the contact angles formed between the liquid and the solid using the Young- Laplace equation, a standard in tensiometry. The right contact angle, left contact angle and average contact angle are displayed on the screen. Data is saved in the instrument.

Measurement data can be transferred wirelessly (WLAN) or via a cable connection to an external computer where the Theta QC Data Receiver Software is installed.
Examples of quality control applications:-
1) Quality control of plasma treated surfacesPlasma treatment is used in number of industries to promote adhesion for example in extrusion coating, flexographic printing, painting and lamination. The homogeneity and efficiency of the treatment can be controlled by measuring contact angle.

2) Quality control of printabilityIn printing, Theta QC is used to control paper and plastic wettability with various inks. Theta QC allows the use of different liquids by simple syringe exchange.

3) Quality control of windshield coatingsHydrophobic coatings deposited on windshields facilitate cleaning and water flow. Coating homogeneity, cleanliness and wettability can be checked by measuring contact angle with Theta QC.

4) Quality control of materials before laminationLamination is used to manufacture multilayer structures, in which the adhesion between materials is crucial. The Theta QC can be used to check the cleanliness and homogeneity of the lamination materials as well as the wettability of chosen adhesives.

5) Quality control of paint wettability Quality of substrate batches may vary and thus affect final quality painted products. Contact angle measurement is an easy and simple way to check wettability and thus get indication of the paint-substrate adhesion.

Industries
Theta QC Optical Tensiometer can be used in virtually any industry where surfaces and interfaces have a role to play. Please find below some of the main areas where optical tensiometry is used for quality control :-·
- surface treatments
· paper and packaging
· surface engineering
· printing
· semiconductors
· laminating
· plastics
 · paints and coatings

Kulim Surface Potential Meter

If there exists a difference in the electrostatic potential between two surfaces and these are put in movement relative to each other there will be a current flowing through an external circuit. This kind of “condensator” was used by Volta and Kelvin to study the differences in Volta potential between various metals. This “condensator” is often also called the Kelvin probe. Yamins and Zisman applied this method to study monomolecular films.1 Since then this method has widely been used for determining the surface potential of monolayers. The design of KSV SPOT is based on these main ideas. The main application area for KSV SPOT is in monolayer studies, but due to its stand-alone property it is also suitable for other areas where surface potential measurements are required.
Insoluble monolayers at the gas/liquid interface are generally characterized by measuring the surface pressure ()- area (A) isotherm. The  - A isotherm is characteristic for any given ampiphile2 or mixtures of ampihphilic molecules. Many substances show a variety of different monolayer phases.3,4 The major phases are easily recognized in the isotherm as sharply separated regimes with different compressibility. Although the measurement of  as a function of A can give valuable information about monolayers (area per molecule, collapse pressure, phase transition pressures and temperatures, mixing behavior of two or more amphiphiles etc) it may not reveal all of the desired information.
A complementary and a more sensitive way to characterize a floating monolayer is to measure the changes in the surface potential, V.5 This is possible due to the fact that an insoluble monolayer at the gas/liquid interface changes the surface potential through this interface. This change equals the Volta potential between the surface of the liquid and that of the metal probe. Normally only the changes in V due to the presence and changes in the state of the monolayer are measured. In this case the clean liquid surface is fixed to the value 0 mV, and the spread monolayer gives the obtained V. V can be used to determine the composition of the monolayer, the dissociation degree of an ionisable monolayer, the orientation and reorientation of the monolayer molecules at the interface during compression.3,5,6,7,8 By measuring V one can also reveal the interaction between the molecules in the monolayer much earlier than by measuring . The type of deposition that has occurred for LB films (X, Y or Z deposition) has also been determined by measuring the V.9

Kulim Surface Potential Meter

KSV SPOT is a small computer controlled stand alone surface potential measuring instrument. It is based on the non-contact and non-destructive vibrating plate capacitor method. KSV SPOT has a high accuracy, minimal drift and high reproducibility, which guarantee a high sensitivity and stability for the measurements.
KSV SPOT is mainly designed for monolayer measurements, but due to its stand-alone property it is also suitable for surface potential measurements over a range of solids and liquids.
KSV SPOT enables you to complement surface pressure - area data with the more sensitive surface potential data. Thus, giving you for example the following additional information about your Composition, Dissociation degree, Orientation, Interaction, Adsorption of your monolayers

Kulim LB

Kulim SPR BioNavis