Emily Norvell

Cal Poly, San Luis Obispo

Project Title: Electroless Deposition of Silver Metal into Silica Aerogels
Advisor: Professors Jeffrey Youngblood and Kevin Trumble

Introduction

Silica aerogels are very light nanoporeous materials created by using supercritical drying in the sol-gel process of creating ceramics in order to prevent surface tension of the liquid to collapse the structure. The removal of the liquid while keeping the structure intact means that the aerogel is very fragile and brittle and has an extremely high surface area. Because of its high surface area it is desired to be combined with metal for possible catalytically uses that a high surface area metal would be useful for.

Project Objectives

My objective for this project was to fill the pores of silica aerogel with films of particles of silver via electroless in order to create a new structure and to study its composition and properties.

Approach

I tested varying concentrations, times and temperatures of silvering solution by using glass slides to find the ! best combination to use with aerogels
  • Silvered aerogels by placing them in the silvering solution and pulling a vacuum to suck all the air out of the pores
  • Used the optical microscope, SEM, and XRD to get an idea of the nature of the composite

Findings

From my work I have discovered that silver can be effectively deposited into silica aerogels with a silvering solution while being pulled under a vacuum. It was found by the silvering of glass slides that full concentration the silvering recipe used left to silver for roughly 24 hours at room temperature was the best combination although the effects of the freezing temperatures caused by the use of the vacuum were not taken into account or studied.

By the use of the XRD it was confirmed that metallic silver had plated into the aerogel although due to difficulties with the SEM and the lack of time it was not determined if the silver plated in particles of films


A silvered piece of a silica aerogel.
An unsilvered piece of silica aerogel.

Contact me: enorvell@calpoly.edu