Poly Gilch route

Poly(p-xylylene) polymer and copolymers will become thermally crosslinkable, if they contain acyclohexenyl moiety [50]. Suchpolymers can be prepared via the Gilch route [51] as shown in Figure 2.7. 

The sulfonium precursor route may also be applied to alkoxy-substituted PPVs, but a dehydrohalogenation-condensation polymerization route, pioneered by Gilch, is favored 37]. The polymerization again proceeds via a quinomethide intermediate, but die syndicsis of the conjugated polymer requires only two steps and proceeds often in improved yields. The synthesis of the much-studied poly 2-methoxy-5-(2-ethylhexyloxy)-l,4-phenylene vinylene], MEH-PPV 15 is outlined in Scheme 1-5 33, 35]. The solubility of MEH-PPV is believed to be enhanced by the branched nature of its side-chain. 

T. Ahn, S. Ko, J. Lee, and H. Shim, Novel cyclohexylsiyl — or phenylsiyl-substituted poly(p-phe-nylene vinylene)s via the halogen precursor route and Gilch polymerization, Macromolecules, 35 3495-3505, 2002. 

The firsX(lO) and the second/"//J methods are known to be Wessling-Zimmerman method and Gilch-Wheelwright polymerization, respectively. The last reaction route is practically the same as that is utilized in the synthesis of poly(/ -xylylene) from /7-xylene via the CVD polymerization method. The first two methods have been widely used not only in the synthesis of PPV but also PPV derivatives. Since the methods produce soluble precursor polymers, the final polymer can be obtained in various shapes. 

However, we need to note that other chemical routes, rather than oxidation polymerization, can also be applied for conducting polymer synthesis. For example, polymers such as poly(pheny lene vinylene), poly(phenylene ethynylene), and their derivatives are usually synthesized using the Wittig reaction (Wittig and Schollkopf 1954), Heck reaction (Heck and Nolley 1972), and Gilch... 

Ahn, T., Ko, S.W., Lee, J., Shim, H.K. Novel Cyclohexylsilyl- or phenylsilyl-substituted poly(p-phenylene vinylene)s via the halogen precursor route and Gilch polymmzation. Macromolecules 35, 3495-3505 (2002)... 

---