Functionalized nanoporous polyethylene derived from miscible block polymer blends

Functionalized nanoporous polyethylene (PE) was prepared through controlled introduction of thermo-responsive poly[2-(2-methoxyethoxy)ethyl methacrylate] (PMe(OE)₂MA), or poly{2-[2-(2-methoxyethoxy)ethoxy]ethyl methacrylate} (PMe(OE)₃MA) onto the pore walls. The compatibility of polylactide (PLA) and PMe(OE)_xMA (x = 2, 3) was investigated by blending the corresponding homopolymers. The blends showed only one glass transition when the molar masses of both components were relatively low, whereas two glass transitions were observed in case of higher molar mass samples. PMe(OE)_xMA-b-PE-b-PMe(OE)_xMA (x = 2, 3) block polymers were synthesized by a combination of ring-opening metathesis polymerization, atom transfer radical polymerization, and hydrogenation. Those block polymer blends formed a disordered bicontinuous structure consisting of a mixed PLA/PMe(OE)_xMA domain and a semicrystalline PE domain. The PLA component was selectively removed from those blends by mild base treatment. The resulting nanoporous polyethylene showed an improved water uptake as a result of the hydrophilic PMe(OE)_xMA on the pore walls.