Dynamical heterogeneity in the gelation process of a polymer solution with a lower critical solution temperature.
Soft Matter
; 17(11): 3222-3233, 2021 Mar 21.
Article
em En
| MEDLINE
| ID: mdl-33624665
ABSTRACT
The gelation of a hydrophobically modified hyaluronic acid aqueous solution which shows a lower critical solution temperature of about 25 °C was investigated by multi-particle tracking microrheology. The linear viscoelasticity of the gelling system is converted from the microrheological data. The critical gelling temperature Tgel = 36.3 °C was determined from the loss tangent by the Winter-Chambon criterion. The critical exponent n = 0.62 was determined from the shift factors of the time-cure superposition. The length scales of the dynamic heterogeneity of the gelling system were analyzed using a proposed framework where single-particle and multi-particle non-Gaussian parameters were compared. The length scale of the dynamic heterogeneous regions monotonically decreases during the gelation process, consistent with the nucleation-and-growth mechanism of phase separation. Distributions of local viscosity in the gelling system were extracted from the observed distributions of particle displacement as a time-dependent fingerprint of the dynamic heterogeneity of the gelling system. The results and analyzing methods proposed in the present work can be applied to other microrheological studies.
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Bases de dados:
MEDLINE
Idioma:
En
Revista:
Soft Matter
Ano de publicação:
2021
Tipo de documento:
Article
País de afiliação:
China