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Interaction of water with poly‐α‐amino acids. I. Relationships between conformation and relaxation processes
Author(s) -
Shiraishi H.,
Hiltner A.,
Baer E.
Publication year - 1976
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1976.360150611
Subject(s) - chemistry , rigidity (electromagnetism) , relaxation (psychology) , drop (telecommunication) , side chain , crystallography , chemical physics , stereochemistry , thermodynamics , organic chemistry , polymer , psychology , social psychology , telecommunications , physics , structural engineering , computer science , engineering
The relaxation behaviour of the sodium salt of poly ( L ‐glutamic acid) in the solid state has been examined by means of dynamic mechanical spectroscopy. Bound water was found to exert a profound influence on the relaxation behaviour and on a bulk property, the rigidity. Certain features of the loss spectrum have been identified with the hydration‐dependent β‐to‐α conformational transition. Thus two side‐chain relaxations are observed below ambient temperature, one associated with the β from (β 1 β ) and a second at a lower temperature associated with the α form (β 1 α ). The greater rigidity of the α form below the relaxation temperature and the larger rigidity drop accompanying the β 1 α can be explained in terms of the structural differences of the two conformations.