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NANOSCALE RESEARCH AT THE UNIVERSITY OF MASSACHUSETTS AMHERST IN THE MATERIALS RESEARCH SCIENCE AND ENGINEERING CENTER on Polymers (MRSEC DMR-0820506) Todd Emrick, Director, University of Massachusetts Amherst The Materials Research Science and Engineering Center (MRSEC) at the University of Massachusetts Amherst supports the research programs of 29 faculty drawn from 6 campus departments as well as 8 faculty from 4 different colleges. The research activities of the Center are organized into two Interdisciplinary Research Groups (IRGs), one Superseed and two Seed efforts. Substantial research efforts in the Center involve nanoscale features of polymer materials. Outreach programs link the Center to other research universities, undergraduate colleges, local primary and secondary schools, and industrial and government laboratories. thermal annealing PS-b-PEO thin film coating Templated hierarchical self-assembly of block copolymer Chemical patterning on SAM via electro- oxidation nanolithography thermal annealing PS-b-PEO thin film coating Templated hierarchical self-assembly of block copolymer Chemical patterning on SAM via electro- oxidation nanolithography Wrinkles Creases Folds • Fundamental questions remain at boundaries where transition to dominant wavelength proceeds through a series of discrete doublings. • Precisely controlling extended patterns of wrinkles is a major challenge • Fundamental questions remain at boundaries where transition to dominant wavelength proceeds through a series of discrete doublings. • Precisely controlling extended patterns of wrinkles is a major challenge Reversible encapsulation of epithelial cells 100 200 300 400 10 100 1000 Fl. Intensity Time, ns 600 650 700 0 50 100 0 0.5 mM 1.0 mM 1.5 mM 2.0 mM 2.5 mM Fl. Intensity Wavelength, nm Nanoparticle (rod) Conjugated polymer ligands Matrix Morphology & crystallinity of matrix material are key to device performance Matrix and ligands: regioregular poly(3-hexyl thiophene) Nanoparticles: CdSe rods and particles DH Kim et. al Adv. Mater. 2006, 18, 719–723 Nanoparticle (rod) Conjugated polymer ligands Matrix Matrix Morphology & crystallinity of matrix material are key to device performance Matrix and ligands: regioregular poly(3-hexyl thiophene) Nanoparticles: CdSe rods and particles DH Kim et. al Adv. Mater. 2006, 18, 719–723 Morphology & crystallinity of matrix material are key to device performance Matrix and ligands: regioregular poly(3-hexyl thiophene) Nanoparticles: CdSe rods and particles DH Kim et. al Adv. Mater. 2006, 18, 719–723 MAKING CONNECTIONS IRG 1 DIRECTED POLYMER BASED ASSEMBLIES EDUCATION AND OUTREACH PHOTOINDUCED CHARGE TRANSFER: ADDING OPV TO TOPO-CdSe SURFACE CREASING STRUCTURE OF WRINKLES Surface creases form on polymer gels subjected to a critical degree of compression (e.g., due to confined swelling) Instability is remarkably scale-invariant, with feature sizes roughly equal to film thickness. Deformation field involves lateral micro-scale motion of surface, without application of macroscopic strain JACS 2004 & 2006 J. Phys. Chem. 2006 JACS 2008 Dispersion from grafting Aggregation from blending JACS 2004 & 2006 J. Phys. Chem. 2006 JACS 2008 Dispersion from grafting Aggregation from blending EFFECT OF SURFACE COVERAGE ON QD PHOTOPHYSICS Director T. Emrick Associate Directors K.R. Carter, Research S.P. Gido, Shared Facilities R. Hayward, Education/Outreach MRSEC Associates M. Achermann, Physics M. Barnes, Chemistry H. Bermudez, PSE A. Briseno, PSE K.R. Carter, PSE A. Crosby, PSE B. Davidovitch, Physics J. Davis, Chemical Engineering A. Dinsmore, Physics T. Emrick, PSE S.P. Gido, PSE G. Grason, PSE R. Hayward, PSE D.A. Hoagland, PSE S.L. Hsu, PSE A.J. Lesser, PSE T.J. McCarthy, PSE N. Menon, Physics M. Muthukumar, PSE V. Rotello, Chemistry J. Rothstein, Mech. Indus. Engr. T.P. Russell, PSE M. Santore, PSE G. Tew, PSE S. Thayumanavan, Chemistry M. Tuominen, Physics D. Venkataraman, Chemistry P. Wadsworth, Biology J.J. Watkins, PSE Outreach Partners D. Raghavan, Howard University W. Chen, Mt. Holyoke College N. Easaar, Smith College M. Ozkan, UC Riverside Professional Staff G. Dabkowski, Outreach Coordinator J. Green, Education Outreach Manager J. Hirsch, Surface Science L. Raboin, Electron Microscopy C. Russell, VISUAL Program Mgr. Shared Facilities Directors W. Hu, NMR S. Eyles, Mass Spectroscopy A. Mel'cuk, Computing A. Ribbe, Photovoltaic D. Thirunavukkarasu, Nanostructures and X-ray FOSTER PUBLIC AWARENESS INORGANIC NANOROD/POLYMER NANOWIRE HYBRIDS WRINKLE DEVELOPMENT c REU program RET program Middle school curricula On-site laboratory program (ASPIRE) Graduate student K-12 outreach Graduate Education and Career Development Initiative PolyMerge (K-12 initiative) Public exhibits Symposia Publications National and international competitions VISUAL FUNDAMENTAL CHALLENGES FUNDAMENTAL CHALLENGES Generation and assembly of polymer building blocks with well-defined functionalities and architectures Combing synthetic polymers with synthetic or naturally occurring nanoparticles Merging theoretical and experimental expertise towards advancing directed assembly OBJECTIVES OBJECTIVES IRG 2 POLYMER SURFACE INSTABILITIES SEED 2 POLYMER BASED OPTOELECTRONICS Polythiopene with Electron Accepting Pendent Groups Develop techniques to precisely direct growth of elastic instabilities into long-range hierarchies extending over a broad range of lengthscales (nm m). Investigate how materials properties, microstructure, geometry and driving force affect surface patterns. Use polymer surface instabilities to control and understand material properties. Thermal and osmotic swelling as triggers Multiple materials compositions exhibit similar transitions DIRECTING PATTERNS TO SOFT MATERIALS ORDERING ON SOFT, FLEXIBLE SUBSTRATES Reconstructed Sapphire PBT Replica PS-b-PEO Annealed in o-xylene vapor 2 mm x 2 mm The replicated polymer patterns guide the self-assembly of block copolymer thin films by solvent annealing BIJELS Cates et al., Science 309, 298 (2005) DIRECTED SELF-ASSEMBLY OF BLOCK COPOLYMERS ON CHEMICAL PATTERNS CONJUGATED POLYMERS FOR DIRECTED ASSEMBLIES TEM PS PVME/CdSe-TOPO + 2 vol% CdSe nanorods PS/PVME(1:1 vol), 24h@170 o C 2-5 micron domain size with particles CO-CONTINUOUS BLEND STRUCTURES BY NANOROD GELATION 100 micron domain size w/o particles ~3 mm PS/PVME (1:1 vol) w/ 2vol% CdSe- TOPO rod, 48h@170 o C Bicontinuous spinodal microstructures jammed by CdeSe nanorod aggregation (precipitation in the PVME domains
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