Alexandria Digital Research Library

Concentration fluctuations of polymer solutions at interfaces

Author:
Yeh, Catherine Jane
Degree Grantor:
University of California, Santa Barbara. Physics
Degree Supervisor:
Philip Pincus
Place of Publication:
[Santa Barbara, Calif.]
Publisher:
University of California, Santa Barbara
Creation Date:
2013
Issued Date:
2013
Topics:
Physics, General, Physics, Fluid and Plasma, and Chemistry, Polymer
Keywords:
Polymer physics
Square gradient theory
Wetting
Polymer solutions
Surface phase transitions
Fluctuations
Genres:
Dissertations, Academic and Online resources
Dissertation:
Ph.D.--University of California, Santa Barbara, 2013
Description:

The interfacial properties of inhomogeneous systems are most simply described by square gradient theories, which write the free energy as an integral over a functional of the concentration. In this thesis, we study concentration fluctuations in semidilute polymer solutions, in which polymers are overlapping in solution, using a modified (Cahn-de Gennes) square gradient theory. The Cahn-de Gennes theory incorporates correlations from polymer elasticity and has successfully been used in the past to provide mean field descriptions of interfacial energies and concentration profiles in a variety of solvent and boundary conditions. We begin by reviewing the bulk thermodynamics of polymer solutions and correlations due to polymer connectivity to motivate the form of the modified square gradient theory. We then set up the program of calculations and investigate the fluctuations in bulk, phase-separated solutions and in the presence of adsorbing and repulsive surfaces. Fluctuations exhibit particularly interesting behavior at adsorbing surfaces in poor solvent; their divergence at the onset of complete wetting, a type of surface phase transition, is related to capillary waves that are found at the free interface of two coexisting phases in the bulk.

Physical Description:
1 online resource (108 pages)
Format:
Text
Collection(s):
UCSB electronic theses and dissertations
ARK:
ark:/48907/f3rr1wbt
ISBN:
9781303541308
Catalog System Number:
990040925490203776
Rights:
Inc.icon only.dark In Copyright
Copyright Holder:
Catherine Yeh
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