I have TPTA gel of various concentration and want to get an idea of the pore size distribution and its crosslinking density.
Vaidik Rashesh Shah
Pore size can be determined in dried gels, i.e., in solid-gas dispersed systems. Your systems are classified as jellies. Jellies study by other methods, for example, determining structural formation by rheological methods. Crosslinking of chains in polymers is usually proportional to the strength of the jelly ..
Crosslinked gels do not properly speaking display pores with a well defined size R (with a normal or gaussian distribution). They can be more adequately viewed as a network with an anomalous distribution (typically a power law distribution between two boundaries) of mesh-size. Due to this anomalous distribution and depending on how far the system is from the gelation threshold, the average mesh-size depend on the moment of the distribution the measurement method is sensitive. For instance, rheology (measurement of the elastic modulus that is proportional to 1/R) likely leads to an harmonic average which should be much smaller than the value that can be obtained with small angle scattering (eg. neutron) that is a z-average (average of m^2 R^2, with m the mass of polymer of length R).... More details can be found in textbook concerning gels.
Whatever the method used, the important point is that one should not attach much importance on the absolute value of this mean-size but only of its relative variation (eg. from one sample to another).
Dear all, may be you are looking for the swellability of the gel which is a direct indication of both free voluum and crosslinking density. If so, many documents are available on using solvant swelling for such estimations. My Regards
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