Patent ID: 8461287

Claim:
A branched multi-block copolymer, comprising: a hydrophobic block having a plurality of repeating units represented as chemical formula 1; and a hydrophilic block having a plurality of repeating units represented as chemical formula 2, wherein A, X and Y are each independently, R is —NO 2 or —CF 3 , Z is Q is —SO 3 H, —SO 3 − M + , —COOH, —COO − M + , —PO 3 H 2 , —PO 3 H − M + or —PO 3 2− 2M + , and M is Na or K, B is G is X, and G′ is Z, 0<u/t<1, and 0<w/v<1, 0.7<(e+1.5*g)/(f+h)≦0.95 or 0.7<(f+h)/(e+1.5*g)≦0.95, and a+e+1.5(c+g)=f+h+b+d, in which a, b, c, d, e, f, g and h are molar ratios, and the hydrophilic block has a total number of repeating units of 100 to 350.