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arXiv · 1712.04430

Crystal-to-crystal transition of ultrasoft colloids under shear

J. Ruiz-Franco·J. Marakis·N. Gnan·J. Kohlbrecher·M. Gauthier·M. P. Lettinga·D. Vlassopoulos·E. Zaccarelli
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Abstract

Ultrasoft colloids typically do not spontaneously crystallize, but rather vitrify, at high concentrations. Combining in-situ rheo-SANS experiments and numerical simulations we show that shear facilitates crystallization of colloidal star polymers in the vicinity of their glass transition. With increasing shear rate well beyond rheological yielding, a transition is found from an initial bcc-dominated structure to an fcc-dominated one. This crystal-to-crystal transition is not accompanied by intermediate melting but occurs via a sudden reorganization of the crystal structure. Our results provide a new avenue to tailor colloidal crystallization and crystal-to-crystal transition at molecular level by coupling softness and shear.

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J. Ruiz-Franco, J. Marakis, N. Gnan, J. Kohlbrecher, M. Gauthier, M. P. Lettinga, D. Vlassopoulos, E. Zaccarelli. 2017-12-12. Crystal-to-crystal transition of ultrasoft colloids under shear. https://doi.org/10.1103/physrevlett.120.078003

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