PIMs News

A fascinating and efficient new method for making Polymers of Intrinsic Microporosity with highly rigid structures is described in Macromolecules.

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Preliminary data polymers appear to be useful for gas separations.

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Just out.  An important paper from the Colina group (U of Florida) concerning the interpretation  of low pressure gas adsorption data in amorphous microporous polymers, such as PIMs, for obtaining pore size distribution (PSD).  It seem that the strange gap on  porosity at 1.0 nm in NLDFT is just an artefact and the PSD is smoother as predicted by packing simulations.  All experimentalists using N2 adsorption data for the characterisation of the porosity of amorphous polymers should read this.

http://pubs.acs.org/doi/pdf/10.1021/acs.langmuir.7b01961

 

 

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Work by our research group has produced a new polymer of intrinsic microporosity (PIM) with extraordinarily high gas permeability that may result in more efficient separation membranes for large-scale processes such as carbon capture. The ultrapermeability is due to the frustrated packing of 2D polymer chains.

This work is reported in  Nature Materials

An excellent paper on the mechanism of gas adsorption into PIM-1 from Sarti, Paul and Minelli showing that the application of BET analysis is both unnecessary and incorrect for high free volume polymers. The Non-Equilibrium Fluid Lattice (NELF) model is more useful and general for all glassy polymers.    The authors are very diplomatic in suggesting that the nomenclature of the temporally fluxional voids within PIMs might be of “personal preference rather than objective unquestionable arguments”.  The term Polymer of Intrinsic Microporosity was coined (2004) in ignorance of the complexities of gas adsorption.

http://www.sciencedirect.com/science/article/pii/S0376738817310360

(Note that we term the surface areas calculated from nitrogen isotherms are described as “apparent BET surface areas” and recommend this usage for all porous polymers.)