"NIRT: FUNCTIONAL NANOPARTICLE FORMATION BY BLOCK COPOLYMER DIRECTED ASSEMBLY"
This proposal was received in response to the Nanoscale Science and Engineering initiative, NSF 04-043, category NIRT. Based on their newly discovered process to produce nanoparticles by block copolymer-controlled rapid precipitation, the PIs plan to develop a comprehensive, fundamental understanding of the kinetics, thermodynamics, and polymer material science that enables the precise control and design of nano-sized particles with unique optical, mechanical, chemical and biological properties. This multidisciplinary team consists of PIs at three institutions (Prud'homme, Kevrekidis, and Panagiotopoulos [Princeton], Macosko [UMinn], and Fox [ISU]), who have a strong record of collaboration that pre-dates this NIRT project.
Their approach to nanoparticle formation, termed "NanoPrecipitation", has three components: (1) rapid and tailored micromixing, (2) high supersaturation to produce rapid nucleation and growth, and (3) stabilizing novel block copolymer that kinetically arrest growth by self-assembly to produce tunable and extremely narrow particle size distributions. The goals are to understand at a basic, that is molecular, level how a nanoparticulate system is formed and to apply this knowledge to engineer novel nano materials. Understanding requires input from simulations to model complex interactions across multiple scales: turbulent micromixing at a macroscopic scale, block copolymer assembly and nucleation and growth at a microscale. A simultaneous experimental effort, informed by the simulations, is required to provide basic data on assembly kinetics and particle size distributions to validate the simulations. Nanoparticle formation by "NanoPrecipitation" depends critically on control of four time scales: (1) micromixing time in novel reactors to produce supersaturation; (2) particle nucleation and growth time; (3) the time scale for reactive coupling to form block copolymers, and (4) block copolymer self-assembly to effect steric stabilization time. The research is organized around these timescales, with each aspect requiring an integrated program of experimental research and multi-scale modeling. Simulations at the microscopic level provide insight into formation mechanisms and inputs into the modeling at the mesoscale where the interplay of transport and chemistry controls assembly. Macroscale modeling integrates simulation results from the finer scales, and provides the design tools so that nanoparticle formation can be manipulated to produce novel functional nano materials with applications in medicine, printing and manufacturing.
Intellectual merit: The PIs hope to develop multi-scale simulation tools that open new research areas beyond the reach of current simulation strategies which are incapable of addressing multiple length scales or system sizes beyond a few tens of molecules.
Broader Impacts: Advances in understanding and controlling the process of nanoparticle formation will extend beyond the direct applications in drug delivery and inkjet printing to a wide range of applications requiring functional nanoparticles of controlled size. Graduate researchers and undergraduate participants will be trained in research projects that are inherently interdisciplinary and infused with real-world applications.
