Bicontinuous nanospheres from simple amorphous amphiphilic diblock copolymers

Bicontinuous nanospheres have been observed (although rarely) from a variety of block copolymers with architectural and compositional complexity, and often in the presence of additives. Unlocking key features involved in their formation presents possibilities for bicontinuous aggregates with varied functionality and application. An attractive prospect is the ability to form them from much simpler polymeric structures derived from facile syntheses. To that end, we herein report the formation of bicontinuous aggregates from simple amorphous amphiphilic diblock copolymers of poly(ethylene oxide)-b-poly(n-butyl methacrylate), analogous to our previous report of the same from a semicrystalline comb-like block copolymer. Moreover, we demonstrate that polymorphism can be achieved by altering the relative block proportions and the nonselective cosolvent. We find that the polymeric structure is not the dominating factor in the formation of bicontinuous nanospheres but that the choice of cosolvent for the hydrophilic block appears to have greater influence on determining the end morphology.