Membrane processes can cover a wide range of separation problems [with a
specific membrane (membrane structure) required for every problem]. Thus,
there are membranes available that differ in their structure and consequently in
the functionality. Therefore membrane characterization is necessary to ascertain,
which membrane may be used for a certain separation. Membranes of pore size
ranging from 100nm to 1μm with a uniform pore size are very important in
membrane technology. An optimum performance is achieved when the
membrane is as thin as possible having a uniform pore size.
Here in this thesis, membranes were synthesized by particle assisted wetting
using mono-layers of silica colloids as templates for pores along with
polymerizable organic liquids on water surface. The pore size reflects the
original shape of the particles. Thus it is possible to tune the pore size by
varying the particle size. This method is effective to control pore sizes of
membranes by choosing silica particles of suitable size.
This approach gives a porous structure that is very thin, but unfortunately
limited in mechanical stability. Thus there is a need for support which is robust
and can withstand the various mechanical stresses. A small change in the
membrane or defect in the layered structure during the membrane formation can
have drastic effect on the assembly. Lateral homogeneity of the layer generated
by the particle assisted wetting can be judged by examination of its reflectivity,
but once it is transferred on any solid support this option is no more.
So a method is needed to detect the cracks or the inhomogenity of the
membrane which can be detected even after the transfer. To tackle this problem
a very simple and novel technique for characterizing the membrane by
fluorescence labeling and optical inspection was developed in this thesis. The
idea was to add a fluorescent dye which is poorly water soluble to the spreading
solution comprising of the particles and the monomer. If the dye survived the
photo-cross linking, then it would be embedded in the cross-linked polymer and
would serve as a marker. Defects and inhomogenity would show up as cracks
and spots. By the method that we have developed, we can detect our membrane
from the support and spot defects.
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:19284 |
| Date | 25 March 2010 |
| Creators | Rane, Mahendra |
| Contributors | Goedel, Werner A., Lehmann, Matthias, Technische Universität Chemnitz |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | doc-type:doctoralThesis, info:eu-repo/semantics/doctoralThesis, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
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