We evaluated the effectiveness of a silicone membrane as an alternative to human skin using the skin permeation parameters of chemical compounds. An in vitro permeation study using 15 model compounds was conducted, and permeation parameters comprising permeability coefficient (P), diffusion parameter (DL(-2)), and partition parameter (KL) were calculated from each permeation profile. Significant correlations were obtained in log P, log DL(-2), and log KL values between the silicone membrane and human skin. DL(-2) values of model compounds, except flurbiprofen, in the silicone membrane were independent of the lipophilicity of the model compounds and were 100-fold higher than those in human skin. For antipyrine and caffeine, which are hydrophilic, KL values in the silicone membrane were 100-fold lower than those in human skin, and P values, calculated as the product of a DL(-2) and KL, were similar. For lipophilic compounds, such as n-butyl paraben and flurbiprofen, KL values for silicone were similar to or 10-fold higher than those in human skin, and P values for silicone were 100-fold higher than those in human skin. Furthermore, for amphiphilic compounds with log Ko/w values from 0.5 to 3.5, KL values in the silicone membrane were 10-fold lower than those in human skin, and P values for silicone were 10-fold higher than those in human skin. The silicone membrane was useful as a human skin alternative in an in vitro skin permeation study. However, depending on the lipophilicity of the model compounds, some parameters may be over- or underestimated.
Hi all, first post here but I've been lurking in the threads for some time, very informative and helpful community! I'm working on creating realistic human busts,the process is going well for the most part, but I'm struggling greatly with making the skin feel more human-like. Specifically, the "grab" of the silicone.If you run your finger across the back of your hand (or any of your skin), your finger will gently glide along the surface. With silicone, being the rubber that it is, there's a great deal of friction and grab, and you have to really apply a bit of extra force to slide your finger across a patch of silicone. I've tried Ecoflex OO-30, DragonSkin FX Pro (2A shore hardness), and a long time back, Platsil Gel 10. All seem to have that grab on the surface, really detracting from feeling like skin, instead feeling more like rubber (which would make sense I supposeSmooth-On manufactures something specifically for this purpose ( https://www.smooth-on.com/products/slide-std/) , but not being able to paint the silicone afterwards, and also not being able to adhere new silicone to the STD-mixed silicone, wouldn't work in my process.I read something awhile back about applying baby powder/talcum powder to silicone, not sure if that's relevant? So, if anyone has any advice on some method for reducing the friction/grab on silicone to make it feel more like human skin, or any alternative silicones I could purchase that might exhibit these properties, I'm all ears! Thanks!