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Understanding Structure and Response in Thermally-Responsive Block Copolymer Assemblies Robert B. Grubbs, SUNY at Stony Brook, DMR 1105622. The structures that result from the self-assembly of polymers have potential applications in medicine, catalysis, sensing, and other areas.
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Understanding Structure and Response in Thermally-Responsive Block Copolymer AssembliesRobert B. Grubbs, SUNY at Stony Brook, DMR 1105622 The structures that result from the self-assembly of polymers have potential applications in medicine, catalysis, sensing, and other areas. We have been investigating block copolymers designed to form small spherical assemblies at low temperatures and larger hollow assemblies above a critical temperature (LCST; see Figure 1). The first polymer systems we examined took up to one month to form larger structures, so a key goal has been the design of faster switching systems. In the past year, we have developed a new family of acrylamide-based block copolymers (Figure 2) that appear to show a rapid change in size when the temperature is increased (Figure 3). Our ongoing work is directed at better understanding the fundamental behavior of these and related polymers Figure 1. Representation of small polymer assemblies formed at low temperatures (T < LCST) and larger hollow assemblies formed at higher temperatures (T > LCST). PEO-PDEA (Mn = 5.0 kg/mol; Ð = 1.25) Figure 2. Synthesis of new responsive triblock copolymer PEO-PDEA-PDBA (left); Size exclusion chromatography traces showing increases in polymer molecular weight from PEO-CTA polymer to PEO-PDEA diblock copolymer to PEO-PDEA-PDBA copolymer (right). PEO-CTA (1.2 kg/mol; Ð = 1.19) PEO-PDEA-PDBA (6.8 kg/mol; Ð = 1.34) PEO-PDEA PEO-PDEA-PDBA Figure 3. Solutions of PEO-PDEA-PDBA triblock copolymer in water (1 mg/ml) at room temperature (left) and after 10 minutes at 60 °C (right). The cloudiness of the heated solution is indicative of the formation of large polymer assemblies. Room Temperature
Understanding Structure and Response in Thermally-Responsive Block Copolymer Assemblies Robert B. Grubbs, SUNY at Stony Brook, DMR 1105622 • Broader Impacts: • Continued to develop government-academic collaborations through a joint appointment at the Center for Functional Nanomaterials (CFN) at Brookhaven National Laboratory (BNL). • Served as a member of the editorial advisory boards of Macromolecules, Journal of Polymer Science Part A, and Polymer Chemistry. • Made presentations to undergraduate students in the Nuclear Chemistry Summer School at BNL on applying to graduate school and to students at Ningbo University on careers in science. • Involved one high school student and two undergraduate students in research in the summer of 2011. Grubbs Research Group, 8/2012 (from left to right): Naveen Mallangada (HS student), Tianyuan Wu (4th year PhD student), Zhe Sun (2nd year PhD student), Gabbi Dusharm (Stony Brook ‘13), Bingyin Jiang (4th year PhD student), Ryan Dill (UC San Diego ‘13). Students in bold participated in this project. Not pictured: Dr. Young Park (BNL), Deokkyu Choi (1st year graduate student), Kenneth Miller (1st year graduate student), and Daniel Yi (1st year graduate student).