Vinylidene fluoride methyl radicals

Solution polymerization. Solution polymerization involves polymerization of a monomer in a solvent in which both the monomer (reactant) and polymer (product) are soluble. Monomers are polymerized in a solution that can be homogeneous or heterogeneous. Many free radical polymerizations are conducted in solution. Ionic polymerizations are almost exclusively solution processes along with many Ziegler-Natta polymerizations. Important water-soluble polymers that can be prepared in aqueous solution include poly(acrylic acid), polyacrylamide, poly(vinyl alcohol), and poly(iV-vinylpyrrolidinone). Poly(methyl methacrylate), polystyrene, polybutadiene, poly(vinyl chloride), and poly(vinylidene fluoride) can be polymerized in organic solvents. 

The use of reverse ATRP enlarges the scope of substrate polymers for controlled polymerizations even further because the required radical initiators can in many cases be provided more easily than ATRP initiators on surfaces of inert polymers. For example, poly(vinylidene fluoride) microfiltration membranes were irradiated with UV light and then exposed to air to create hydro(peroxide) species [11]. These were then used to initiate the reverse ATRP of methyl methacrylate in the presence of copper(I) chloride, 2,2 -bipyridine, and benzoylperoxide (Figure 3.5). Similar reaction schemes are applicable to (hydro)perox-ide patterns created directly on polymer surfaces using the lithographic methods discussed in Chapter 2. 

Methyl radicals are only moderately electrophilic and differ considerably in their reactivity towards fluoro-olefins compared with the more electrophilic trichloromethyl and heptafluoro-n-propyl radicals. In Table 1 are shown the ratios of attack at either end of vinyl fluoride, vinylidene fluoride. 

Poly(vinylidene fluoride) n Poly(l,l-difluoroethylene) Poly(vinylidene fluoride) is made by free radical vinyl polymerization of the monomer vinylidene fluoride Poly(vinylidene fluoride) of PVDF has a has very high electrical resistance, PVDF resists ultraviolet and is often blended with poly(methyl methacrylate) (PMMA) to make it more resistant to UV light. It is a piezoelectric material and when placed in an electric field wiU change its shape. 

Proton conductivities of the terpolymers prepared by free-radical copolymerization of vinylidene fluoride with 8-bromo-perfluorinated-l-octene and sulfonated methyl-dioctene have been found to be orders of magnitude lower than those of Nation [144]. 

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