placement in a culture dish. Cracks on the order of 0.5-1.0 ipm were observed, and

appeared mainly as positive textures pushing up from the surface. Since the

transformation of the material from PDMS to a silica-like oxidized layer results in a large

decrease in specific volume, tensile stresses are formed in the oxidized layers. These

stresses are relaxed by the cracking and result in an elevated texture, as seen and

explained by Hillborg, Sandelin, and Gedde.[116]

 Of concern also is the affect that the plasma treatment has on the shape and size of

the features. Profilometry data presented in Figure 3.8 shows a very dramatic change in

the height of the ridges, changing from 1.43 pm to 0.81 pm. It is apparent that the

plasma treatment at this level is ablating the surface and seriously altering the features.


 1.06

 Surface Stats:
 Ra: 72.08 nrn 70
 Rq: 137.05 mn o50
 RtI: 2.08 um


 Measurement Info: .
 Ma.niflcati.ll 5150 .
 Measurente Mode: VSI J -0 30
 Sampling: 163.10 nm
 Array Size: 736 X 480


 .1 01
 Title: 1.5 um 15% tris
 Note: Plasma treated smooth


Figure 3.5 Profilometer image of surface damage due to plasma of 15% vinyl tris
textured elastomer sample (smooth area)