Nanoscience and Microsystems ETDs

Publication Date

Spring 5-14-2022

Abstract

The Cyphochilus white beetle has received significant attention recently for its exceptional visible-light-scattering properties, owing to the beetle scale's anisotropic nano-fibrillar network structure. Inspiration from the remarkable optical properties of these biological species has directed research efforts to fabricating biomimetic nano-fibrillar structures with polymer materials. In this work, electrospun silk fibroin polymer films reproduce the white beetle scale's anisotropic nature to draw on its optical scattering properties and further improve the radiative-cooling capabilities of silk fabrics. An anisotropically restructured silk film with a mean fiber diameter of a few hundred nanometers substantially increases optical scattering strength in the visible spectrum and emissivity in the mid-infrared atmospheric transparency window compared to raw nonwoven silk fabric. The restructured silk fibrous film reduces the average bulk temperature of the electrospun thin film by 7.5 °C relative to raw silk fabric under sunlight. The strong scattering response of the electrospun fibrous films enables highly efficient cooling fabrics and suggests electrospinning as a reliable approach for producing passive radiative-cooling structures.

Document Type

Dissertation

Language

English

Degree Name

Nanoscience and Microsystems

Level of Degree

Doctoral

Department Name

Nanoscience and Microsystems

First Committee Member (Chair)

Sang Eon Han

Second Committee Member

Sang M. Han

Third Committee Member

Andrew Shreve

Fourth Committee Member

Bryan Kaehr

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