Macromolecules, Vol.40, No.26, 9279-9283, 2007
Quantitative in situ coupling of living diblock copolymers for the preparation of Amphiphilic coil-rod-coil triblock copolymer poly(2-vinylpyridine)-b-poly(n-hexyl isocyanate)-b-poly(2-vinylpyridine)
A facile approach to synthesis of a series of coil-rod-coil triblock copolymers by in situ coupling of living diblock copolymers is reported. The living diblock copolymer poly(2-vinylpyridine)-block-poly(n-hexyl isocyanate) (P2VP-b-PHIC) synthesized by anionic polymerization was coupled using malonyl chloride or suberoyl chloride in the presence of pyridine. The triblock copolymers were obtained in similar to 94 - 99% yields without the need for fractionation or separation. The copolymers showed narrow molecular weight distribution (MWD = 1.08 - 1.14) and good agreement between the calculated and observed molecular weights. In a solvent such as tetrahydrofuran (THF), which is common to both the blocks, the copolymers showed characteristics of microphase separation. With high rod volume fractions lamellar phase separation with long-range order was observed.