Diblock copolymers junction-point-functionalized

Junction-point-functionalized block copolymers were synthesized according to Scheme 3 [34]. Styrene was polymerized first using s-BuIi as initiator. After completion of polymerization a small excess of DMADPE was introduced to the reaction mixture (DMADPE/Ii = 1.2/1). The reaction was left for completion for 3 d at room temperature. Isoprene was then added, polymerized, and terminated by addition of degassed methanol In the case of the triblock copolymer synthesis, after completion of isoprene polymerization, a predetermined amount of a Me2SiCl2 solution in benzene was introduced to the reaction mixture (Cl/Ii = 1/2.2). The coupHng reaction was essentially complete in 3 d. Solvent/nonsolvent fractionation was employed in order to separate the triblock from excess diblock. 

A system of n AB diblock copolymers each with a degree of polymerization N and A-monomer fraction, /, is considered. The A and B monomers occupy a fixed volume, l/g0, and the system is incompressible with a total volume, V, equal to hN/qq. A variable s is used as a parameter than increases continuously along the length of a polymer. At the A monomer end, s = 0, at the junction point, s = f, and at the other end, s = 1. The functions r (s) define the space curve occupied by the copolymer a (Matsen and Schick 1994). 

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