ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
In order to understand the mutual interactions between water and a biopolymer, thermodynamic analysis of sorption isotherms of water vapor by the biopolymer is necessary. These isotherms are irreversible and show sorption hysteresis. The reasons for such behavior are not established. As a continuation of previous work, general relationships for thermodynamic quantities of sorption are derived for the general case when the sorbent consists of two uniform phases. As in the case of a single sorbent phase, the Clausius-Clapeyron equation can be used to obtain differential entropies of sorption. Two special cases for the two-phase situation - equilibrium hysteresis and partial equilibrium hysteresis - are plausible models for the irreversibility seen in water-biopolymer interactions. When differential entropy of sorption is plotted as a function of amount of water sorbed per mole of biopolymer, irregularities are generally seen. It is suggested that these irregularities reflect changes in conformation and/or dynamics of the biopolymer molecule.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.360260307
Permalink