Non-technical abstract Colloids are nano and micrometer sized spheres suspended in a liquid. The aim of this research is to explore and develop methods to direct, or program, the assembly of these particles into specific ordered crystalline arrangements. The ultimate goal is to take colloids made from diverse materials such as polymers, glasses, metals, and semiconductors, suspend them in a water (or some other liquid) and cause them to self-assemble into preprogrammed functional microscopic arrangements. The applications are likely to be in technologies as diverse as optoelectronics, microfluidics, filtration, and catalysis, where the precise arrangement of different types of materials on the microscale is key to their functionality. The research team will use DNA sequences attached to different nano and microparticles, which will be used to program the self-assembly of the microscopic colloidal particles. The team will investigate how these particles move and dynamically arrange themselves to form various crystalline structures and will test theories of how such programmed assembly occurs. The research will train doctoral and postdoctoral researchers in these emerging state-of-the-art methods of colloidal self-assembly.
The goal of this project is to develop a fundamental understanding of the microscopic processes that govern the self-assembly and crystallization of DNA-coated colloids. The work takes advantage of recent breakthroughs developed in the principal investigator's laboratory for creating new DNA coatings for a wide spectrum of colloidal materials. The research team will focus on the dynamics of crystallization in one-component and, as time and resources permit, two-component systems. The experiments will measure the dynamics of phase separation using optical microscopy and light scattering primarily, but will also employ electron microscopy and rheology. The experiments target the different dynamical processes involved in crystal formation at the microscopic (individual particle) level, including nucleation, spinodal decomposition, diffusion, and annealing. DNA-coated colloids represent a new frontier for the self-assembly of advanced materials. Because they possess a number of unique properties, including programmable specific interactions, temperature-dependent pair potentials, and spatially fluctuating surface interactions, they present a number of new scientific challenges related to the frontiers of self-assembly, and modify classical mechanisms of nucleation and growth, anomalous diffusion, and programmable directed diffusion. The research team will develop quantitative models to describe and understand their observations.