Active Response of Polymer Materials from External Stimuli – Solvents and Light; Grafting Reactions on Perovskite Layers

<p>The active response of a series of polymeric materials was investigated. Both solvent activated and light activated thin films and wire systems show dynamic behaviors when exposed to different stimuli.</p> <p>Solvent mediated fluxional behavior of polymer thin films involved extensive, rapid curling both on infusion and evaporation of good solvents. These films can be either lab-fabricated ones or commercial ones, and the curling behavior can be as fast as seconds. Conditions including polymer materials, chosen solvents, and film geometry can affect the behavior.</p> <p>Methods that allowed for the creation and retention of distorted wire structures were also developed; the asymmetric sputtering of metal components on micron-sized wires permitted for the capture of curled wire components on solvent exposure. The asymmetric metal coated wires which were fabricated within a template of glass capillary arrays (GCA) membrane have shown instant (< 1 s) deformation when exposed to the proper solvents. Deformed shapes can be retained or the original linear shape recovered, depending on the metal film thicknesses.</p> <p>Photostimulation of wires was also investigated and showed a notable dynamic response but not as extensive as with the solvent induced behavior. Micron sized wires made with azobenzene-polyacrylate, exhibited a bending behavior when irradiated with 365 nm UV light and recovered under visible light. The bending behavior can be as slow as several minutes per degree while recovery was relatively faster.</p> <p>Additional efforts with polymers involved the formation of polymeric organic-inorganic hybrids where organic monomers, grafted to perovskite layers, were polymerized within the oxide’s interlayers. Reactions were carried out on protonated perovskite, hydrogen lanthanum niobate (HLaNb₂O₇). Alcoxyl groups were first grafted to the oxide and the monomer was substituted by exchange reaction with the alcoxyl groups.</p>

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation-Restricted

Discipline thesis:degree_discipline

Chemistry

Year

2012

Author dc:creator

• Zhang, Jianxia

Contributors dc:contributor

• John B. Wiley

• polymer films
• bending
• azobenzene
• polymer wires
• perovskite
• grafting
• Materials Chemistry
• Nanoscience and Nanotechnology
• Polymer and Organic Materials
• Polymer Chemistry

Repository record dc:identifier

https://scholarworks.uno.edu/td/1498

OAI identifier oai:identifier

oai:scholarworks.uno.edu:td-2394