Microporous polymers morphology

Change in polymer morphology from macroporous to microporous resulted in improved selectivity but a decrease in overall retention, which is desirable in terms of chromatographic performance. For some MIPs uv initiation is not suitable, e.g. when the template is uv sensitive, and thermal initiation is required. In this situation ABDV is favoured since it thermally decomposes at a lower temperature than AIBN (45°C). 

Figure 21. Examples of microporous polymer materials produced by pressure-induced phase separation showing closed-cell and open-cell morphologies.

In addition, we have recently described a procedure for controlling the morphologies of electronically conductive polymers (32). This procedure involves the electrochemical growth of the conductive polymer at an electrode surface which has been masked with a microporous polymer membrane. The pores in this membrane act as templates for the nascent electronically conductive polymer. Because the template membrane contains linear cylindrical pores, cylindrical conductive polymer fibrils are obtained (32). We will show in this manuscript that microfibrillar polypyrrole films prepared via this approach can support higher rates of charge-transport than conventional polypyrrole. 

Figure 3. Schematic representation of the micro- and nanoscale morphology of gel-type (a) and macroreticular (b) resins [13], Level 1 is the representation of the dry materials. Level 2 is the representation of the microporous swollen materials at the same linear scale swelling involves the whole polymeric mass in the gel-type resin (2a) and the macropore walls in the macroreticular resin (2b). The morphology of the swollen polymer mass is similar in both gel-type and macroreticular resins (3a,b). Nanopores are actually formed by the void space surrounding the polymeric chains, as shown in level 4, and are a few nanometer wide. (Reprinted from Ref [12], 2003, with permission from Elsevier.)...

Figure 4. Effect of CO2 pressure on on morphology of macroporous crosslinked polymer monolith, (a) BET surface area (continuous line = total surface area, hed line = micropore surface area) (b) Percent micropore volume (c) Median pore diameter (d) Intrusion volume (macropore volume).

PRA Pradhan, D. and Ehrlich, P., Morphologies of microporous polyethylene and polypropylene crystallized from solution in supercritical propane, J. Polym. Sci. Part B Polym. Phys., 33, 1053, 1995. 

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