Polymer morphology, solvent effects

Besides the choice of monomers and solvent, the ratio of template molecule to functional monomer not only affects the imprinting effect [174] but also the morphology of MIP monoliths. Several authors have observed differences in the monolith structure (polymer morphology, pore size distribution, flow characteristics) between the non-imprinted control polymer and the MIP, derived from the presence of the template [158,175]. For example, an MIP imprinted with ceramide III was compared... 

Not only the rigidity is crucial to the efficiency of MIPs, but also the accessibility as many recognition sites as possible should be accessible for rebinding. The material should therefore be porous. This is realised by dissolving monomers, cross-linkers and print molecules in a porogenic solvent prior to polymerisation. The effect of the solvent on the polymer morphology can be monitored by measuring physical parameters such as surface area, pore diameter and pore volume. 

Similar solvent effects influence the morphology of block polymers of a crystallizable and a noncrystallizable component also. In principle, the poly(ethylene oxide) blocks of the biblock polymer, poly(styrene-Z -ethylene... 

Effective conductivity of the membrane is related to its macroscopic morphology, viz. the random heterogeneous domain structure of polymer and solvent phases. On the basis of Gierke s cluster network model, a random network model of microporous PEMs was developed in [22]. This approach highlighted the importance of connectivity and swelling properties of pores. Random distributions of pores and channels as their interconnections were assumed. The connectivity between pores was considered as a phenomenological parameter. 

It has been reported that polymerization temperature has a considerable effect on particle break-up and, therefore, on the final particle morphology [108, 109]. Maneshi et al. [69] observed that higher polymerization temperatures, up to a certain upper limit, enhanced clay exfoliation. Above this upper limit (which varies depending on the polymer and solvent type) active site and/or polymer chain start being extracted from the clay surface, resulting in poor exfoliation, inadequate powder morphology, and severe reactor fouling. 

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