Engineering Commons^™

Bending, Wrinkling, And Folding Of Thin Polymer Film/Elastomer Interfaces, Yuri Ebata

Open Access Dissertations

This work focuses on understanding the buckling deformation mechanisms of bending, wrinkling, and folding that occur on the surfaces and interfaces of polymer systems. We gained fundamental insight into the formation mechanism of these buckled structures for thin glassy films placed on an elastomeric substrate. By taking advantage of geometric confinement, we demonstrated new strategies in controlling wrinkling morphologies. We were able to achieve surfaces with controlled patterned structures which will have a broad impact in optical, adhesive, microelectronics, and microfluidics applications.

Wrinkles and strain localized features, such as delaminations and folds, are observed in many natural systems and are …

Enhanced Mechanical Performance Of Low Dielectric Constant Thin Films Synthesized In Supercritical Co2, And Sans Studies Of Microemulsions Induced Or Destabilized By Compressed Co2, Alvin Horatio Romang

Open Access Dissertations

Block copolymer (BCP) phase segregation and self-assembly into two or more distinct domains are primarily dictated by two parameters: the block volume fraction, f, and the product of the segment-segment interaction parameter and the length of polymer chain, XN. The volume fraction determines a block copolymer's phase segregated morphology, whereas XN dictates its overall segregation strength, or phase stability. In order to achieve smaller domain sizes, the interaction parameter must be increased to compensate for the decrease in chain length. In the melt, PEO-b-PPO-b-PEO (Pluronic) triblock copolymer surfactants do not phase segregate primarily due to their low molecular weights …

Structure-Property Evolution During Polymer Crystallization, Deepak Arora

Open Access Dissertations

The main theme of this research is to understand the structure-property evolution during crystallization of a semicrystalline thermoplastic polymer. A combination of techniques including rheology, small angle light scattering, differential scanning calorimetry and optical microscopy are applied to follow the mechanical and optical properties along with crystallinity and the morphology. Isothermal crystallization experiments on isotactic poly-1-butene at early stages of spherulite growth provide quantitative information about nucleation density, volume fraction of spherulites and their crystallinity, and the mechanism of connecting into a sample spanning structure. Optical microscopy near the fluid-to-solid transition suggests that the transition, as determined by time-resolved mechanical …