New super-hairy semi-rigid polymers

Living monofunctional poly(tetramethylene oxyde) (PTMO) (THF bulk polymerization initiated at 20 degrees C by methyl triflate) was end capped by reaction with 3-(dimethylamino)propyl isocyanide. Selective and quantitative quaternization of the tertiary amine function results in the straightforward synthesis of PTMO macromonomers of the isocyanide type with a fairly good control of molecular weight and polydispersity, ((M) over bar(n) approximate to 1800-4400, (M) over bar(w)/(M) over bar(n) approximate to 1.2). Their homopolymerization at 40 degrees C in highly concentrated methanol solution (macromonomer weight fraction approximate to 0.80) initiated by NiCl2 quantitatively yields the corresponding poly(macromonomers) of high degrees of polymerization (DPw > 10(3)) and of very unusual and maximum branching density: one graft chain per every backbone carbon atom. According to a semi-quantitative analysis of their radius of gyration, as derived from light scattering measurements (EtOAc-iPrOH 9:1 by vol., Et4N+CF3SO3- 0.05 M), an increase of the intrinsic rigidity (persistence length) of the worm-like poly(isonitrile) backbone induced by the PTMO branches cannot be ruled out. These super-hairy polymers may be considered as exotic comb-shaped cationic poly(amphiphiles) of potential interest as new lyotropic and thermotropic materials.