A block copolymer is disclosed, which comprising the following formula (V):
[D]x-[E]y-[F]z (V)
wherein, D, E, F are each independently as the following formula (VI), and each of D, E, F are different; and x, y, z are each independently an integral from 1 to 40;(VI)wherein, A2 is O or S; R7 is H or C1-6 alkyl; and R8 is C1-12 alkyl, (CH2)qN(R11)2, CH2(CH2OCH2)rCH2N(R12)2, or CH2(CH2OCH2)sCH2OR13, wherein R11, R12 and R13 are each independently C1-6 alkyl; q, r and s are each independently an integral from 1 to 10. |