Silicone rubber surface modification

Keywords Atom transfer radical polymerization, biomaterials, biosurfactants, plasma treatment, polymer brushes, polydimethylsiloxane, silicone rubber, surface modification, voice prostheses... 

Price C, Waters MGJ, Williams DW, Lewis MAO, and Stickler D. Surface modification of an experimental silicone rubber aimed at reducing initial candidal adhesion. J Biomed Met Res, 2002, 63, 122-128. 

Effect of surface modification on pull-out force of PPTA silicone rubber composite ... 

Inagaki, N., Tasaka, S. and Kawai, H. (1992). Surface modification of Kevlar 49 fiber by a combination of plasma treatment and coupling agent treatment for silicon rubber composite. J. Adhesion Sci. Technol. 6, 279-291. 

The surface of PDMS is hydrophobic which results in poor wettability with aqueous solvents and promotes non-specific protein adsorption. It is also relatively inert to chemical modification [25]. The liquid silicon rubber chosen for fabrication of the reaction plate contained pyrogenic silicic acid as a filler. Aside from its effect on elastomer properties the silicic acid can be expected to provide additional silanol... 

The hydrophobicity of the surface prevents the wetting by tear and tends to expose dry surface of a contact lens. Therefore, rapid dehydration of the corneal tissues could occur, which could cause the damage of corneal epithelium. However, this explanation seems to be oversimplified in light of the adsorption of protein, which makes a hydrophobic surface wettable by tear fluid, as described in Chapter 26. Moreover, the highly hydrophobic surface characteristic of silicone rubber tends to encourage the deposition of protein and mucus of the tear on the surface of the lens. Lipids and lipid-soluble materials follow the same track and eventually penetrate into the bulk phase of the contact lens. Because of these undesirable factors, the use of silicone contact lenses of various chemical compositions and with surface treatments has not been successful but rather disastrous because of the interfacial characteristics of silicone contact lens on the cornea, which cannot be oflfset by these efforts. It indicates that more profound surface modification to cope with the problems rather than mere surface treatment is needed in capitalizing on the advantageous bulk properties of silicone polymers. 

Bodas, D. Rauch, J.-Y. Khan-Malek, C., Surface Modification and Aging Studies of Addition-Curing Silicone Rubbers by Oxygen Plasma. Eur. Polym. J. 

Modifications to increase the ratio of surface area to volume for the roller bottle culture include the Spira-Cell Multi-Surface Roller Bottle (Bibby Sterlin, Ltd.), extended surface area roller bottles (ESRB) (Bibby Sterlin, Ltd.), and TexturSil, a silicone rubber matrix that coats roller bottles to increase the surface area (Ashby Scientific, Ltd. Coalville, Leics., U.K.)... 

Khorasani, M.T. and Mirzadeh, H. (2004) Laser surface modification of silicone rubber to reduce platelet adhesion in vitro. J. Biomat. Sci.-Polym. E., 15 (1), 59-72. 

Ultraviolet (UV) or UV/ozone exposure (UVO) is another class of techniques extensively used to modify PDMS surface. Previously, it was reported that when exposed to UV light or a combination of UV and ozone, silicone rubbers underwent drastic surface chemical changes similar to the result of oxygen plasma [29]. However, the UV and UVO modification processes are nearly an order of magnitude slower than the modification by plasma techniques and provide much deeper modification of PDMS surface without cracking or mechanically weakening the PDMS [30]. The treatment results showed that a hydrophilic SiO -like layer formed, and such gradual surface reconstruction of PDMS layer is directly related to the duration of the exposure time [31]. 

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