Patent ID: 8513356

Claim:
A diblock copolymer blend, comprising: >50 wt % to 99 wt % (on a solids basis) of an ordered poly(styrene)-b-poly(methyl methacrylate) diblock copolymer, BCP1, having a polystyrene volume fraction, Vf BCP1-PS , of 0.65 to 0.87; and, wherein the following expression is true χ ⁢ ⁢ N BCP ⁢ ⁢ 1 > [ 1.6 Vf BCP ⁢ ⁢ 1 - PS * ( 1 - VF BCP ⁢ ⁢ 1 - PS ) - 0.098 ] wherein χN BCP1 is the product of the Flory-Huggins interaction parameter, χ BCP1 , of BCP1 at 225° C. and the degree of polymerization, N BCP1 , of BCP1; and, 1 to <50 wt % (on a solids basis) of a disordered poly(styrene)-b-poly(methyl methacrylate) diblock copolymer, BCP2, having a polystyrene volume fraction, Vf BCP2-PS , of 0.5 to 0.99; and, wherein the following expression is true χ ⁢ ⁢ N BCP ⁢ ⁢ 2 < [ 2.6 Vf BCP ⁢ ⁢ 2 - PS * ( 1 - VF BCP ⁢ ⁢ 2 - PS ) ] wherein χN BCP2 is the product of the Flory-Huggins interaction parameter, χ BCP2 , of BCP2 at 225° C. and the degree of polymerization, N BCP2 , of BCP2; wherein the number average molecular weight of BCP1, M N-BCP1 , is 30 to 500 kg/mol; wherein the number average molecular weight of BCP2, M N-BCP2 is 0.1 to <500 kg/mol; and, wherein M N-BCP1 >M N-BCP2 .