Supramolecular self-assembly through inclusion complex formation between poly(ethylene oxide-b-N-isopropylacrylamide) block copolymer and α-cyclodextrin

A well-defined poly(ethylene oxide-block-N-isopropylacrylamide) (PEO-b-PNIPAM) diblock copolymer was synthesized by atom transfer radical polymerization and formed the inclusion complexes (ICs) after selective threading of the PEO segment of the block copolymer through the cavities of α-cyclodextrin (α-CD) units. The formation of the α-CD/PEO ICs between α-CD and PEO segment of the PEO-b-PNIPAM transformed the system from its original random coil conformation into a rod/coil-like structure. The stacking of the α-CD/PEO ICs and phase separation within the α-CD/PEO-b-PNIPAM IC resulted in the self-assembly of long-range-ordered lamellar structure exhibiting alternating layers of (i) α-CD/PEO ICs with hexagonally packed plates and (ii) amorphous phase of unincluded PEO/PNIPAM with brush conformation.