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Crystalline structure of polyacrylonitrile–iodine complex
Author(s) -
Kim Hong Sung,
Cho Hyun Hok
Publication year - 1994
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1994.070531102
Subject(s) - polyacrylonitrile , materials science , intercalation (chemistry) , superstructure , iodine , crystal structure , phase (matter) , crystallography , aqueous solution , chemical engineering , phase transition , polymer chemistry , chemistry , polymer , organic chemistry , composite material , thermodynamics , engineering , metallurgy , physics
The existence of structural order is found in the polyacrylonitrile (PAN)‐iodine complex obtained by immersing PAN film in an aqueous solution of I 2 /KI. We provide an interpretation for the key features of this structural order and for the structural change of PAN by iodine sorbing. The observed diffractions suggest that iodine penetrates into the crystalline phase of PAN at relatively low iodine concentrations and are intercalated between PAN molecular cylinders in the form of polyiodine columns that are composed mainly of I 5 −(most likely the I 2 /I 3 −complex). Pseudohexagonal crystals of PAN are expanded uniaxially by replacement of PAN molecular cylinders by the polyiodine columns. The intercalated polyiodine column layers are arrayed parallel with PAN chain layers in the crystalline phase. The results led to a proposal of an intercalation model for the crystalline structure of the PAN–iodine complex. The crystalline structures are expected to exist with two different types of the polyiodine layers. The crystalline transition between these structures occurs by thermal mobility of PAN chains. © 1994 John Wiley & Sons, Inc.