Preparation Of Reactive Polysiloxane Nanoparticles And Fabrication Of Superhydrophobic Surfaces

Polysiloxane nanoparticles are widely used in many fields due to the excellent characteristics such as heat resistance, weather resistance, physiological inertia and hydrophobicity. Polysiloxane nanoparticles are synthesized via sol-gel and emulsion method with alkylsilanes as precursors in the presence of catalyst in ethanol/water system. Superhydrophobic cotton fabrics are successfully fabricated by coating with the as prepared polysiloxane. This thesis presented the work on the fabrication and functionalization of polysiloxane nanoparticles by adding γ-(2,3-epoxypropyl) propyltrimethoxysilane(GPTMS) with reactive groups for enhancing the binding force between the cotton fabrics and nanoparticles, which are listed as follows:(1) Polypropyl-methyl-epoxysilsesquioxane(PPMGSQ) sol was prepared using methyltrimethoxysilane(MTMS), propyltrimethoxysilane(PTMS) and GPTMS as precursors in isopropyl alcohol system via sol-gel method. Durable superhydrophobic cotton textiles were fabricated with the as-prepared sol via a nonsolvent induced phase separation method. Scanning electron microscope(SEM) was employed to investigate the topography of the textiles. Optical contact angle measuring instrument(OCA) was used to detect the wetting properties of the textiles. The influence of precursor concentrations on the hydrophobic performance of textiles was investigated. The effect of water on cotton textile surface morphology was also studied. The stability of the obtained superhydrophobic textiles was evaluated by abrasion and washing mechanical force. Finally the method for preparation of durable superhydrophobic cotton textiles with PPMGSQ sol was established. The results showed that stable phase separation PPMGSQ sol was obtained by adding appropriate amount of water to as-prepared sol, the contact angle of treated cotton textiles could reach 161°. After 800 cycles of abrasion and 10 cycles of home laundering, the contact angles of cotton textiles were 140° and 145°, respectively. It was shown that the treated cotton textiles showed some durability of abrasion and laundering.(2) Polypropyl-hexadecyl-epoxysilsesquioxane(PPHGSQ) nanoparticles were synthesized with PTMS as precursor followed by modification with HDTMS and GPTMS via emulsion method in water system. The effects of stirring speed, amount of surfactant agent, ammonia and modified agent on the nanoparticle size and stability of the emulsion were investigated. Cotton fabric with excellent superhydrophobicity was prepared by coating fibers with the as-prepared polysiloxane nanoparticles. SEM was employed to investigate the topography of the textiles. The element distribution and composition of the textile surface were measured by EDS. The durability of the superhydrophobic textile was tested by washing and mechanical abrasion. Finally the method for preparation of durable superhydrophobic cotton textiles with PPHGSQ nanoparticles was established. The excellent superhydrophobic cotton textiles with contact angle of 164.5° were fabricated with polysiloxane nanoparticles. After 800 cycles of abrasion and 10 cycles of home laundering, the contact angles of cotton textiles were 135° and 155°, respectively.