Membrane Gas Separation

2 
Gas Permeation Parameters 
and Other Physicochemical 
Properties of a Polymer of Intrinsic 
Microporosity ( PIM - 1)
Peter M. Budd 
a
, Neil B. McKeown 
b
, Detlev Fritsch 
c
, Yuri Yampolskii 
d

and Victor Shantarovich 
e


a
Organic Materials Innovation Centre, School of Chemistry, University of Manchester, UK
 
b
School of Chemistry, Cardiff University, UK
c
Institute of Polymer Research, GKSS Research Centre Geesthacht GmbH, Geesthacht, Germany

d
A. V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, 
Moscow, Russia

e
N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, Moscow, Russia
2.1
Introduction 
Membrane technologists are well aware that the most permeable glassy polymers are 
those which possess a very high free volume, where the term ‘ free volume ’ refers to the 
intermolecular voids within a material [1] . Scientists who work with molecular sieves, 
such as zeolites, commonly use the term ‘ microporous material ’ to describe those materi-
als which contain pores or channels less than 2 nm in width, a defi nition that arises in the 
context of gas adsorption studies [2] . 
Two questions can thus be asked. 
1 Can the macromolecular backbone of a polymer be designed to generate a large amount 
of interconnected free volume?

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Membrane Gas Separation
2 If so, does the polymer then behave like a molecular sieve, specifi cally in terms of gas 
adsorption?
If the answer to both these questions is ‘ yes ’ , then the polymer can be said to have ‘ intrin-
sic microporosity ’ [3,4] ; ‘ intrinsic ’ because it is a consequence of the molecular structure 
and ‘ microporosity ’ because we are dealing with ‘ micropores ’ in the sense defi ned by 
IUPAC [2] . This chapter introduces a concept for creating just such polymer structures, 
outlines the properties of the archetypal ‘ polymer of intrinsic microporosity ’ , PIM - 1, and 
describes recent results for PIM - 1 obtained in the course of a European collaborative 
research project [5] .