CHAPTER 3
 CHARACTERIZATION OF SILICONE ELASTOMER SUBSTRATES


 Introduction

 The first step in this project was to fully characterize the silicone elastomers and

textured substrates. Four separate formulations of silicone elastomer with functionalized

additives and four with non-functional additives were used to vary the elastic modulus.

The surface energy of each formulation was measured by contact angles of solvents with

varying surface tensions. Dynamic contact angles in water were taken of the unmodified

silicone elastomer with and without texture. Samples were treated with both

radiofrequency glow discharge (RFGD) plasma and adsorbed fibronectin. Textured

surfaces were provided at two depths of features, and the fidelity of the surface pattern

was characterized by non-contact optical profilometry.


 Materials

 The base elastomer system, referred to in this thesis as "unmodified", is the

Silastic T-2 Silicone Moldmaking Rubber produced by Dow Coming. The resin is a

dimethylvinyl-terminated polydimethylsiloxane (PDMS) composite mixture composed of

PDMS and trimethylated silica for mechanical stability. It is a translucent resin that cures

via addition polymerization with a platinum catalyst when added in a 100:10 ratio with

the Silastic T-2 curing agent. The typical properties of the base resin and elastomer

system are given in Table 3.1. Resin was provided in 45 lb. containers and curing agent