Chemical vapor deposition graft polymerization

The techniques of graft polymerization have been developed for liquid as well as gas phase. One of the polymerization techniques comprises impregnation of cellulose by a solution of conjugated monomers, followed by soaking in a relevant initiator. Chemical vapor deposition (CVD) of poly(3,4-ethylenedioxythiophene) is another, solvent-less technique, used for thin layer deposition of conjugated polymer on fibers [33]. Three CVD methods have been developed physical vaporization CVD [34, 35], plasma-enhanced CVD [36], and thermally initiated CVD [37, 38]. However, low conductivity is achieved when dopants are not used. 

Figure 2 presents the most common plasma-based surface modification techniques for biomedical applications, described in more detail later plasma assisted chemical vapor deposition or PACVD (RF, MW), physical vapor deposition or PVD (sputtering, cathodic arc), plasma polymerization and grafting, plasma-based thermochemical treatments (e.g. plasma nitriding), ion implantation, plasma immersion ion implantation or PHI, and plasma spraying. Each technique has unique advantages and applications, and the choice of the more adequate technique often depends on the... 

On the other hand, chemicals might be chosen as agents for generation of active centers in the polymeric backbone and grafting of monomer in the vapor phase. Ammonium persulfate and styrene (189), acrylic acid (190), butyl acrylate (191), potassium persulfate and n-butyl maleate or 2-ethyl hexyl acrylate (55,134) and ammonium ceric nitrate and methacrylic add (192) are examples of this method. Benzoyl peroxide deposited on polycaprolactam fibers initiates the grafting of styrene in vapor phase (193). 

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