Directing Colloidal Assembly and a Metal-Insulator Transition Using a Quench-Disordered Porous Rod Template

Abstract

Replica and effective-medium theory methods are employed to elucidate how to massively reconfigure a colloidal assembly to achieve globally homogeneous, strongly clustered, and percolated equilibrium states of high electrical conductivity at low physical volume fractions. A key idea is to employ a quench-disordered, large-mesh rigid-rod network as a templating internal field. By exploiting bulk phase separation frustration and the tunable competing processes of colloid adsorption on the low-dimensional network and fluctuation-driven colloid clustering in the pore spaces, two distinct spatial organizations of greatly enhanced particle contacts can be achieved. As a result, a continuous, but very abrupt, transition from an insulating to metallic-like state can be realized via a small change of either the colloid-template or colloid-colloid attraction strength. The approach is generalizable to more complicated template or colloidal architectures.

Thermoresponsive Stiffening with Microgel Particles in a Semiflexible Fibrin Network

“…The semiflexible nature also strongly modifies the nature of physical entanglements and influence of chemical cross-linking on the mechanical response, resulting in structural and dynamical length scales that are very different from their flexible counterparts . From a property perspective, using a large mesh semiflexible polymer network presents several opportunities for novel material design − and have already found applications in tissue-engineering and cell culture scaffolds , because of such distinctive structural and dynamic mechanical properties, and they offer new mechanisms of developing stimuli-responsive systems that are fundamentally different from the flexible polymer-based composite systems.…”

“…From a property perspective, using a large mesh semi-flexible polymer network presents several opportunities for novel material design [7,8], especially biopolymer networks which are ubiquitous in living organisms. As background, we recall that biopolymer networks are present as both intracellular scaffolds and extracellular matrices which are vital for the structural integrity of biological structures [9][10][11], and play key roles in physiological processes such as cell migration, cytokinesis and mechano-responsiveness [12][13][14][15].…”

Screening and collective effects in randomly pinned fluids: a new theoretical framework

“…It is well-known that spatial confinement effects substantially vary glassy dynamics of a system compared to its bulk counterpart [4,5]. There are many ways to design confinement: pinning molecules and/or particles [6][7][8][9][10][11], quenching network [12] or using surfaces and interfaces [13][14][15][16]. Dynamics of confined systems can be slower [13][14][15][16] or faster [17][18][19] since molecular mobility strongly depends on properties of surfaces, boundaries and finite-size effects.…”

Fluids with competing interactions. I. Decoding the structure factor to detect and characterize self-limited clustering

“…Competing interactions between particles or molecules that manifest at distinct lengthscales can generate hierarchical structure in soft matter systems 1 . For contexts as diverse as microemulsions 2 , block-copolymers 3,4 , graphene oxides 5 , and confined fluid mixtures [6][7][8] , this type of constituent frustration drives (often abrupt) transformations between homogeneous states and morphologies exhibiting micro-to mesoscopic density fluctuations. Such modulated density fluctuations are typically classified as "intermediate-range order" (IRO) because, for this class of morphologies, the structure factor S (k) displays a characteristic pre-peak at a low but nonzero wavenumber [9][10][11][12][13][14][15][16][17][18][19] .…”