Center for Functional Nanomaterials Seminar

Custom designed nanoparticles (NP) or colloids with specific recognition offer the possibility to control the phase behavior and structure of particle assemblies for a range of applications. One approach to realize these new materials is by attaching single-stranded DNA to a core NP. By appropriate choice of base sequence, the hydbridization of double-stranded DNA will link NP, allowing for control of NP assembly. In this seminar, I will discuss a molecular model for DNA-linked NP. We examine how the number and orientation of strands affects the structure, phase behavior, and dynamics. We show that the NP can form networks with very open structure, due to long DNA linkages relative to core NP size, resulting in a multitude of thermodynamically distinct phases, both amorphous and crystal. We further examine the parameters that control the thermodynamical stability of crystalline NP arrays, since these ordered systems are expected to be important for applications, and are challenging to form experimentally. Finally, we show that existing theoretical framework from polymer physics can be adapted to quantitatively explain the growth and cluster structure from numerical simulations.