The self-assembly behavior of block polymers under strong two-dimensional and
three-dimensional confinement has been well-studied in the past decade. Confinement effects
enable access to a large suite of morphologies not typically observed in the bulk. We have used
nanoporous polyethylene, derived from a polymeric bicontinuous microemulsion, as a novel
template for the confinement of several different cylinder-forming block polymer systems:
poly(isoprene-b-2-vinylpyridine), poly(styrene-b-isoprene), and poly(isoprene-b-dimethylsiloxane).
The resultant materials exhibit unique hierarchical arrangements of structure with two distinct
length scales. First, the polyethylene template imparts a disordered, microemulsion-like periodicity
between bicontinuous polyethylene and block polymer networks with sizes on the order of 100 nm.
Second, the block polymer networks display internal periodic arrangements produced by the
spontaneous segregation of their incompatible constituents. The microphase-separated morphologies observed are similar to those previously reported for confinement of block polymers in
cylindrical pores. However, at present, the morphologies are spatially variant in a complex manner,
due to the three-dimensionally interconnected nature of the confining geometry and its distribution
in pore sizes. We have further exploited the unique structure of the polyethylene template to
generate new hierarchically structured porous monoliths. Poly(isoprene-b-2-vinylpyridine) is used as
a model system in which the pyridine block is cross-linked, post-infiltration, and the polyethylene
template is subsequently extracted. The resultant materials possess a three-dimensionally
continuous pore network, of which the pore walls retain the unique, microphase-separated
morphology of the confined block polymer.