Graduation Date

Summer 8-14-2020

Document Type

Thesis

Degree Name

Master of Science (MS)

Programs

Medical Sciences Interdepartmental Area

First Advisor

Mark W. Beatty

Abstract

Current materials used for facial prostheses are far from being desirable, and improved properties with “skin-like” feel are needed. This study evaluates property changes induced by sequential additions of uncoated and hydrophobic-coated nano-SiO2 to polydimethylsiloxane (PDMS) and compares them with those measured for conventional submicron SiO2-filled materials. Each filler type was sequentially added to vinyl-terminated PDMS at 0%, 0.5%, 5%, 10%, and 15% by weight. Tensile, tear, Durometer hardness, translucency and viscoelastic properties were evaluated, with hardness and translucency also evaluated following 3000 hours of outdoor weathering. Results demonstrated that 15% coated nano-SiO2-filled PDMS materials produced the highest tensile strength, elastic modulus, storage modulus, loss modulus, tear strength, and durometer hardness (p2-filled materials demonstrated the highest failure strain and translucency parameter (p2 PDMS materials, but the increases were deemed too low to be clinically detectable. Only unfilled and 0.5%-filled PDMS formulations darkened from weathering, as higher filler levels offered protection against solar radiation, heat and moisture. It was concluded that superhydrophobic-coated nano-SiO2-filled PDMS favorably produced the strongest, most tear resistant and least translucent materials, but also generated low stretch ability and high hardness that were considered to be unfavorable in achieving a “skin-like” feel.

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