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Study of structure and dynamics of gelatin gels by temperature ramped holographic relaxation spectroscopy
Author(s) -
Wu Chi,
Schrof Wolfgang,
Lilge Dieter,
Lüddecke Erik,
Horn Dieter
Publication year - 1990
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19900400116
Subject(s) - gelatin , molecule , diffusion , chemistry , relaxation (psychology) , gel point , materials science , analytical chemistry (journal) , polymer chemistry , polymer , crystallography , chromatography , thermodynamics , organic chemistry , social psychology , psychology , physics
A technique combined temperature ramp with holographic relaxation spectroscopy (HRS) is used to investigate on the structure and dynamics of gelatin gels. Two kinds of photochromic probes are used. The first is the gelatin molecule covalently labeled with fluorescein‐isothiocyanate. After gelation, some of the labeled gelatin molecules will form the gel and the rest will still be in the sol. Therefore, the mobility of labeled gelatin molecules in the sol and the gel are probed. The translational diffusion coefficient of gelatin molecules in the sol, the gel content and the gel melting temperature at different gelatin concentrations ranging from 1 to 15 weight‐% are measured. The second probe is the small fluorescein molecule in the gelatin gel as a tracer. The mobilities of the tracer in the “gel” are probed. An HRS curve with double peaks is observed. It is experimentally proven that this “anomalous” HRS curve is related to the structure of the gelatin gels. During a normal cooling process (2 C/min), two kinds of networks are found. A “coarse” one is formed through the aggregation of collagen‐like triple‐stranded helices and a “fine” one is formed simply by entanglements between gelatin molecules.