2.4. Rod–coil–rod triblock copolymers
Both the grafting-from and grafting-onto methods had been used to prepare rod–coil–rod triblock copolymers. In the former, copolymerization of 5-acetyl-2-aminobenzophenone with diacetyl functionalized polystyrene (PS) to give the PPQ-b-PS-b-PPQ triblock copolymer ( Scheme 11(a)) [66]. On the other hand, a phenyleneethynylene (OPE) trimer with amino and iodo end groups was coupled with a carboxyl acid-terminated polystyrene (PS) and followed by the reaction of 1-ethynyl-4-(phenylethynyl)-benzene to afford PPE-b-PS-b-PPE ( Scheme 11(b)) [90] and [91].