Novel Structures from Polymer-Salt Mediated Interactions in Microfluidics Channels
G.C. Kini, J.T. Lai, M.S. Wong, S.L. Biswal
Rice University, US
Keywords: microfluidics, laminar flow, diffusion, mixing, nanoparticle, capsule, self-assembly, droplet, gel, gel network
Abstract:Microfluidics have been used to form functional colloidal structures such as droplets, microcapsules, Janus particles and multiple emulsions with control over size distribution, shape and composition. To date, most colloidal structures developed in microfluidics are based on flow focusing or fluid instabilities that require a water immiscible organic phase, which oftentimes limits applications in food and medicinal sectors. In this study, we describe methodologies to create a host of novel structures such as polymer-salt aggregates, polymer gels, droplets and nanoparticle-assembled capsules (NACs), using environmental benign aqueous reactants. Electrostatic interactions between reactants constituting cationic polymers, multivalent anions and nanoparticles under laminar flow and diffusion limited mixing conditions in microfluidics, result in a host of novel structures over those derived when reactants are vortex-mixed in beakers under turbulent and convection dominant mixing conditions. Anticipated applications of these structures are as drug delivery agents, advanced separation devices in membranes and as encapsulating agents.