Topology evolution and gelation mechanism of agarose gel

Jun Ying Xiong, Janaky Narayanan, Xiang Yang Liu*, Tan Kok Chong, Shing Bor Chen, Tai-Shung Chung

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

119 Scopus citations

Abstract

Kinetics as well as the evolution of the agarose gel topology is discussed, and the agarose gelation mechanism is identified. Aqueous high melting (HM) agarose solution (0.5% w/v) is used as the model system. It is found that the gelation process can be clearly divided into three stages: induction stage, gelation stage, and pseudoequilibrium stage. The induction stage of the gelation mechanism is identified using an advanced rheological expansion system (ARES, Rheometric Scientific). When a quench rate as large as 30 deg C/min is applied, gelation seems to occur through a nucleation and growth mechanism with a well-defined induction time (time required for the formation of the critical nuclei which enable further growth). The relationship between the induction time and the driving force which is determined by the final setting temperature follows the 3D nucleation model. A schematic representation of the three stages of the gelation mechanism is given based on turbidity and rheological measurements. Aggregation of agarose chains is promoted in the polymer-rich phase and this effect is evident from the increasing mass/length ratio of the fiber bundles upon gelation. Continuously increasing pore size during gelation may be attributed to the coagulation of the local polymer-rich phase in order to achieve the global minimum of the free energy of the gelling system. The gel pore size determined using turbidity measurements has been verified by electrophoretic mobility measurements.

Original languageEnglish (US)
Pages (from-to)5638-5643
Number of pages6
JournalJournal of Physical Chemistry B
Volume109
Issue number12
DOIs
StatePublished - Mar 31 2005

ASJC Scopus subject areas

  • Surfaces, Coatings and Films
  • Physical and Theoretical Chemistry
  • Materials Chemistry

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