Disclosed are self-assembling diblock copolymers of the formula (I): wherein R1 is —(CHR—CH2—O)p—R′, p=2-6, R is H or methyl, and R′ is H, C1-C6 alkyl, or C3-C11 cycloalkyl, R2 is C6-C20 aryl, one of R3 and R4 is C6-C14 aryl or heteroaryl, and the other is C1-C22 alkoxy, and n and m are independently 2 to about 2000, which find use in preparing self-assembled structures and porous membranes. Embodiments of the self-assembled structures contain the diblock copolymer in a cylindrical morphology. Also disclosed is a method of preparing such copolymers.