About the Seminar:
Gels are perhaps the most misunderstood of everyday materials. We begin by providing robust thermodynamic definitions of particulate gels [1], a journey which blends phase separation with one of the great materials science challenges of our time: the glass transition [2-3]. We have made significant steps in addressing the glass transition, and present a unification scenario for the competing theoretical approaches, revealing that in fact the so-called glass wars may be understood as different facets of the same phenomenon [4]. Applying these concepts to solidification in basic model gels formed of colloidal particles [5] enables us to determine their failure mechanisms, crucial for many applications where mechanical failure is (mistakenly) perceived by the consumer as irreversible product degradation.
Going to lengthscales much smaller than those pertinent for micron-sized colloids, using the new technique of nano-real space analysis [6], made possible by the advent of super-resolution imaging [7], we exploit soft matter self-assembly concepts to engineer novel assemblies of proteins and enzymes. By assembling suitable proteins, which may be designed with de novo protein methodology, we are able to produce a platform for a new class of materials with energy and chemical synthesis applications. So far, we have assembled networks of fluorescent proteins with controllable domain size, along with enzymes that exhibit electron transfer and model biochemical reaction pathways as a proof of principle [8].
[1] CP Royall, SR Williams and H Tanaka H, “Vitrification and gelation in sticky spheres”, J. Chem.Phys. 148 044501 (2018).
[2] CP Royall and SR Williams “The role of local structure in dynamical arrest”, Phys. Rep., 560
1 -75 (2015).
[3] CP Royall, F Turci, S Tatsumi, J Russo and J Robinson, “The race to the bottom: approaching
t he ideal glass?”, J. Phys.: Condens. Matter 30 363001 (2018).
[4] F Turci, CP Royall and T Speck “Non-Equilibrium Phase Transition in an Atomistic Glassformer:
t he Connection to Thermodynamics”, Phys. Rev. X, 7 031028 (2017).
[5] CP Royall, SR Williams, T Ohtsuka and H Tanaka, “Direct observation of a local structural
mechanism for dynamic arrest”, Nature Materials 7 556-561, (2008).
[6] JE Hallett, F Turci and CP Royall, “Local structure in deeply supercooled liquids exhibits
g rowing lengthscales and dynamical correlations”, Nature Commun. 9 3272 (2018).
[ 7] SW Hell “Nanoscopy with Focused Light” Nobel Prize Lecture (2014).
[8] I Rios de Anda, A Coutable-Pennarun, C Brasnett, S Whitelam, A Seddon, J Russo, JLR
Anderson and CP Royall, ArXiV 1911.05857 (2019).
About the Speaker:
CP Royall interested in tackling key unsolved problems in everyday materials. He combines computer simulations and novel experiments where suspensions of micron-sized colloidal particles, whose Brownian motion leads them to obey statistical mechanics in the same way as atoms and molecules, are imaged in 3D at the single-particle level. This two-pronged approach is uniquely powerful for tackling a wide range of problems in condensed matter. Key areas of interest include the nature of glass, the role of amorphous structures in understanding self-assembly, and the influence of networks in materials, such as gels and mobility graphs in dynamical arrest.
