An Experimental and Theoretical Determination of Oscillatory Shear-Induced Crystallization Processes in Viscoelastic Photonic Crystal Media.

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Article
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Abstract

A study is presented of the oscillatory shear-ordering dynamics of viscoelastic photonic crystal media, using an optical shear cell. The hard-sphere/"sticky"-shell design of these polymeric composite particles produces athermal, quasi-solid rubbery media, with a characteristic viscoelastic ensemble response to applied shear. Monotonic crystallization processes, as directly measured by the photonic stopband transmission, are tracked as a function of strain amplitude, oscillation frequency, and temperature. A complementary generic spatio-temporal model is developed of crystallization due to shear-dependent interlayer viscosity, giving propagating crystalline fronts with increasing applied strain, and a gradual transition from interparticle disorder to order. The introduction of a competing shear-induced flow degradation process, dependent on the global shear rate, gives solutions with both amplitude and frequency dependence. The extracted crystallization timescales show parametric trends which are in good qualitative agreement with experimental observations.

Publication Date
2021-09-14
Online Publication Date
2021-09-14
Acceptance Date
2021-09-03
Keywords
composite materials, photonic crystals, polymers, shear-induced crystallization, viscoelasticity
Journal Title
Materials (Basel)
Journal ISSN
1996-1944
1996-1944
Volume Title
14
Publisher
MDPI AG
Sponsorship
Engineering and Physical Sciences Research Council (EP/L027151/1)