Fabrication Of Piezoelectric-Superhydrophobic Films And Mechanically Enhanced Photochromic Films

Specific functional elements can be integrated into functional films through the different designs and fabrication approaches of films, which can gain specific properties of separation, adsorption, piezoelectricity, stimuli-responsibility and self-healing. As a result, the development of functional film materials has become heated interest around the world. In this dissertation, there are two kinds of functional films that have been fabricated using different fabrication approaches and designs:1. Piezoelectric fibrous films of poly(vinylidenefluoride-co-trifluoroethylene)(P(VDF-Tr FE)) were fabricated by electrospinning method. A superhydrophobic electrospun layer, comprising P(VDF-Tr FE) and fluorinated-decyl polyhedral oligomeric silsequioxane(F-POSS), was provided to introduce self-cleaning and anti-contamination functions on the piezoelectric fibers. The superhydrophobic property of the materials is extremely stable because of the introduction of F-POSS. With experiencing O2 plasma treatment for a long time, the films also keep stably superhydrophobic and self-healing superhydrophobic, and possess strong piezoelectric response by spraying water.2. We utilized exceptional mechanical property of polyurethane(PU)/poly(acrylic acid)(PAA) composites and excellent photochromic performance of polyoxometalate(POM)/poly(ethylenimin)(PEI) composites to produce these films by the layer-by-layer technique, illustrating the layer-by-layer method can greatly integrate different functions into macroscale structures. And compared with original PU films(ultimate strength: σUTS =19.47 MPa; and ultimate strain: ε UTS =341%), there are encouraging mechanical properties from composite films by the layer-by-layer technique, involving ultimate strength: σUTS =30.14 MPa; and ultimate strain: εUTS =387%. These films, which are greatly rigid, ductile, transparent and photochromic, can be designed and prepared for safety glass.