Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- Ab initio (1)
- Adhesion (1)
- Anion exchange membrane fuel cell (1)
- Colloid (1)
- Composition (1)
-
- Confinement (1)
- Creasing instability (1)
- Dependence (1)
- Elastomers (1)
- Fuel cell (1)
- Hydrogels (1)
- Interaction (1)
- Ionic block copolymers (1)
- Lithography (1)
- Mechanical instabilities (1)
- Mechanical properties (1)
- Membrane (1)
- Metal cation (1)
- Morphology (1)
- Morphology-conductivity relationship (1)
- Parameter (1)
- Patterning (1)
- Polymer (1)
- Proton transfer (1)
- Surface energy (1)
- Thermodynamic (1)
- Triflic acid (1)
Articles 1 - 5 of 5
Full-Text Articles in Polymer Chemistry
Patterning And Mechanical Analysis Of Fiber-Based Materials, Samuel A. Pendergraph
Patterning And Mechanical Analysis Of Fiber-Based Materials, Samuel A. Pendergraph
Doctoral Dissertations
The ability to define and control the topography of a surface has been studied extensively due to its importance in a wide variety of applications. The control of a non-planar topography would be very valuable since a number of structures that are pervasive in artificial applications (e.g. fibers, lenses) are curved interfaces. This potential of enabling applications that incorporate non-planar geometries was the motivation for this thesis. The first study of this thesis comprises the study of patterning the circumference of micrometer sized fibers. Specifically, a unique technique was described to pattern the fiber with a periodic array of colloids. …
Creasing Instability Of Hydrogels And Elastomers, Dayong Chen
Creasing Instability Of Hydrogels And Elastomers, Dayong Chen
Doctoral Dissertations
CREASING INSTABILITY OF HYDROGELS AND ELASTOMERS MAY 2014 DAYONG CHEN, B.S., TIANJIN UNIVERISTY M.S., TIANJIN UNIVERSITY M.S., UNIVERSITY OF MASSACHUSETTS AMHERST Ph.D., UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Ryan C. Hayward Soft polymers placed under compressive stress can undergo an elastic creasing instability in which sharp folds spontaneously form on the free surfaces. This process may play an important role in contexts as diverse as brain morphogenesis, failure of tires, and electrical breakdown of soft polymer actuators. While the creasing instability has been used for collotype printing since as early as the 1850s, the scientific appreciation of this instability …
Composition Dependence Of The Flory-Huggins Interaction Parameter In Polymer Blends: Structural And Thermodynamic Calculations, Travis H. Russell
Composition Dependence Of The Flory-Huggins Interaction Parameter In Polymer Blends: Structural And Thermodynamic Calculations, Travis H. Russell
Doctoral Dissertations
Flory-Huggins Theory has been the basis for understanding polymer solvent and blended polymer thermodynamics for much of the last 60 years. Within this theory, a parameter (χ) [chi] was included to quantify the enthalpic energy of dispersion between distinct components. Thin film self-assembly of polymer melts and block copolymers depends critically on this parameter, and in application, χ has generally been assumed to be independent of the concentrations of the individual components of the system. However, Small-Angle Neutron Scattering data on isotopic polymer blends, such as polyethylene and deuterated polyethylene, have shown a roughly parabolic concentration dependency for …
Ab Initio Studies Of Proton Transport In Proton Exchange Membranes, Jeffrey Keith Clark
Ab Initio Studies Of Proton Transport In Proton Exchange Membranes, Jeffrey Keith Clark
Doctoral Dissertations
A molecular-level understanding of the factors that contribute to transport properties of proton exchange membranes (PEMs) for fuel cell applications is needed to aid in the development of superior membrane materials. Ab initio electronic structure calculations were undertaken on various PEM ionomer fragments to explore the effects of local hydration, side chain connectivity, protogenic group separation, and specific side chain chemistry on proton dissociation and transfer at low hydration. Cooperative interactions between both intra- and inter-molecular acidic groups and hydrogen bond connectivity were found to enhance proton dissociation at very low degrees of hydration. The energetics associated with proton transfer …
Ionic Copolymers For Alkaline Anion Exchange Membrane Fuel Cells (Aaemfcs), Tsung-Han Tsai
Ionic Copolymers For Alkaline Anion Exchange Membrane Fuel Cells (Aaemfcs), Tsung-Han Tsai
Doctoral Dissertations
The advantages of alkaline anion exchange membrane fuel cells (AAEMFCs) over proton exchange membrane fuel cells is the motivation for this dissertation. The objectives of this dissertation were to develop durable membranes with high anion conductivity and an understanding of the ion conductivity relationship with morphology. The research results presented in this dissertation focuses on developing different architectures of ionic copolymers including diblock copolymers and random copolymers for AAEMFCs. A novel, and stable cobaltocenium cation, was incorporated into polymer for stable AAEM. Because of its 18 electron closed valence-shell configuration, the cobaltocenium cation is promising for use in AAEMFC. Two …