Structural, microrheological and kinetic properties of a ternary silica-Pluronic F127-starch thermosensitive system

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:514

Article

Petkova-Olsson, Yana¹  Oelschlaeger, Claude²  Ullsten, Henrik¹  Jarnstrom, Lars¹ 

[1] Karlstad Univ, Dept Engn & Chem Sci, Univ Gatan 2, S-65188 Karlstad, Sweden

[2] Karlsruhe Inst Technol, Inst Mech Proc Engn & Mech, Gotthard Franz Str 3, D-76131 Karlsruhe, Germany

关键词: Thermosensitive;    Silica-pluronic-starch;    Sol-gel transition;    Kinetic;    Microrheology;    Microstructure;   

DOI  :  10.1016/j.jcis.2017.12.051

来源: Elsevier

【 摘 要 】

Hypothesis: The sol-gel transition in aqueous suspensions consisting of silica particles and thermosensitive polymer is controlled by inter-particle forces and solution properties of the polymer. Addition of a second non-thermosensitive polymer may affect the transition. The purpose of this work was to characterize the kinetics of the sol-gel transition and to understand the effects of a second non-thermosensitive polymer on the microstructure, using a combination of classical rheology and microrheology. Experiments: Classical rotational rheology as well as two microrheology methods, Multiple Particle Tracking (MPT) and Diffusing Wave Spectroscopy (DWS), were used to investigate the sol-gel transition of a ternary silica-Pluronic F127-starch thermosensitive system. Findings: Classical rheometry and DWS indicated sol-gel transition temperature similar to 25 degrees C at 1 wt% Pluronic, independently of the concentration of the other components. DWS showed a fast gelation process, less than two minutes for all samples, beside a second slow kinetic process. In the gel state, MPT indicated micro-structural and micro-viscoelastic differences compared to rotational rheology. This was explained by formation of an elastic matrix of silica and polymers in combination with assembly of silica particles in large macroporous agglomerates. Presence of starch led to breakdown of the macro porous network, leaving the homogeneous elastic network left. (C) 2017 The Authors. Published by Elsevier Inc.

【 授权许可】

Free