DAVID MORSE

Research in my group aims to improve our theoretical understanding of complex polymer liquids. We use a combination of analytic and computational approaches. Much of our recent work has focused on self-assembled equilibrium structures of systems that contain block copolymers or on the dynamics and rheology of liquids and gels containing polymers with stiff backbones.

Our work on systems that contain block copolymers has relied heavily on the use of numerical self-consistent field theory (SCFT) to predict equilibrium structures, and has often been motived by and/or carried out in collaboration with experimental colleagues. Recent work along these lines has included analysis of complex morphologies in both triblock and diblock copolymer melts, and analysis of the use of block copolymers as surfactants in immiscible polymer blends. We are now working on theoretical methods that attempt to systematically improve upon SCFT by taking into account the effects of the collective composition fluctuations that SCFT ignores.

Studies of solutions and networks of rigid backbone polymers are motivated in part by the important structural roles played by semiflexible protein filaments such as F-actin in cellular biology. We are trying to provide a sound understanding the rheology of solutions and gels of such polymers on the basis of a wormlike chain model of polymer conformations, in both dilute and highly entangled concentration regimes. Our work in this area has included both analytic theory, and the use of Brownian dynamics simulations to characterize chain motion in highly entangled solutions.

Awards

• Fellow of American Physical Society, elected 2009
• Gauss Professor, University of Goettingen, 2009-2010

Selected Publications

• Chain motion and viscoelasticity in highly entangled solutions of semiflexible rods; S. Ramanathan and D.C. Morse, Phys. Rev. E 76, 010501 (2007).
• SCFT study of non-frustrated ABC triblock copolymer melts, C.A. Tyler, J. Qin, F.S. Bates and D.C. Morse, Macromolecules 40, 4654 (2007)
• Ultra-low interfacial tension of polymer/polymer interfaces with diblock copolymer surfactants, K. Chang, C.W. Macosko, D.C. Morse, Macromolecules 40, 3819 (2007).
• Diffusion of copolymer surfactant to a polymer/polymer interface, D.C. Morse, Macromolecules 40, 3831 (2007).
• A Brownian dynamics algorithm for entangled wormlike threads, S. Ramanathan and D.C. Morse, J. Chem. Phys. 126, 094906 (2007).
• Block copolymer surfactants in immiscible homopolymer blends: swollen micelles and interfacial tension, K. Chang and D.C. Morse, Macromolecules 39 7746 (2006)
• Diagrammatic analysis of correlations in polymer liquids: cluster diagrams via Edwards' field theory, D.C. Morse, Annals of Physics 321, 2318 (2006). (arxiv cond-mat/0602465).
• Landau theory of the orthorhombic Fddd phase, A. Ranjan and D.C. Morse, Phys. Rev. E 74, 011803 (2006).
• The orthorhombic Fddd network in triblock and diblock copolymer melts, C.A. Tyler and D.C. Morse, Phys. Rev. Lett. 94, 208302 (2005).
• Theory of constrained Brownian motion, Advances in Chemical Physics, vol. 128, 65 (2004).
• Stress in self-consistent field theory, C.A. Tyler and D.C. Morse, Macromolecules 36 , 8184 (2003).
• Linear elasticity of cubic phases in block copolymer melts by self consistent field theory, C.A. Tyler and D.C. Morse, Macromolecules 36, 3764 (2003).
• Theory of linear viscoelasticity of semiflexible rods in dilute solutions, V. Shankar, M. Pasquali, and D.C. Morse, J. Rheology 46 1111 (2002)
• A Rouse-like model of liquid crystalline polymer melts: director dynamics and linear viscoelasticity, D. Long and D.C. Morse, J. Rheology 46, 49 (2002)
• Dynamics of kink bands in layered liquids: theory and in situ SAXS experiments on a block copolymer melt, L. Qiao, D.C. Morse, and K.I. Winey, Macromolecules 34, 7858 (2001)
• Tube diameter in tightly entangled solutions of semiflexible polymers, Phys. Rev. E 63, 031502 (2001)
• Viscoelasticity of concentrated isotropic solutions of semi-flexible polymers. 1. model and stress tensor; 2. linear response, D.C. Morse, Macromolecules 31, 7030, 7044 (1998).