Active Self-assembly Driven by Chemistry: Enhanced Kinetics, Reduced Errors, Novel Patterns and Adaptive Nanostructures

Rensselaer Polytechnic Institute, Troy NY

Investigators

Abstract

0933583 Shi Intellectual Merit: This project seeks to understand active self-assembly of chemically driven nanoscale building blocks using multi scale simulations. Motivated by natural systems, self assembly technique offers spontaneous, massively parallel structure formation from bottom-up. So far, most research efforts have been focused on static self assembly that is thermally driven towards a thermodynamic equilibrium. Significant challenges remain on how to control the kinetics, assembly defects and to broaden the types of structures that can be self-assembled. Less attention has been paid to dynamic self assembly that evolves to a non equilibrium steady state under a dissipative driving force. Indeed, dynamic self assembly is the dominant assembly mode in biological systems that ought to be learned. A few investigations on dynamic self-assembly utilized either macroscopic building blocks under non chemical forces, or biological building blocks propelled by biomolecular motors. However, the self assembly of nanoscale building blocks driven by chemical reactions, which is more relevant to today's nanofabrication techniques, is largely unexplored. Using state of the art simulation techniques, active self assembly of nanoscale building blocks will be investigated. The dissipating chemical energy will be introduced by means of exothermic catalytic reactions. These reactions can influence the assembly process by: (1) providing a mechanical driving force via a chemomechanical coupling; (2) inducing a conformational change of the building blocks; (3) altering the chemical composition, temperature and flow of the environment. Therefore, the dissipative chemical force can influence the momentum, interaction and shape of the building blocks as well as the fluid environment. As a consequence, active self assembly should possess attractive properties including enhanced kinetics, reduced assembly errors, adaptability and novel assembly patterns. Through this proposed effort, molecular-level understanding of the complex behavior of active self assembly will be developed, the benefits of active self assembly will be demonstrated and the design rules for experimental realization will be distilled. Broader Impacts: The broader scientific impacts are two fold. First, the dynamic self assembly considered here, i.e., the assembly process of nanoscale building blocks driven by catalytic chemical reactions, provides an attractive, fully tunable system to investigate the non equilibrium pattern formation. The insights revealed here will have broad implications in physics, biology and social science. Second, the suite of simulation techniques to be developed is unique that is capable of modeling hydrodynamics, diffusion, catalytic chemical reactions and conformational changes concurrently. Thus it can be used to study diffusion reaction coupling, energy conversion processes and other bio-mimetic systems at the molecular level. The PI is devoted to building a long term out reach partnership with the Troy High School. The planned activities include delivering lectures to the high school students and organizing science tours to Rensselaer, in an effort to attract underrepresented students into science and engineering. The research tools developed in this effort, including the simulation, visualization and analysis software, will be freely available to researchers worldwide.