Solid Crystal Network of Self-Assembled Cyclodextrin and Nonionic Surfactant Pseudorotaxanes

Abstract

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The formation of host–guest complexes between surfactants and cyclodextrins

“…Although the formation of pseudorotaxanes (complexes in which a linear chain rapidly and reversely threads through a cyclic molecular bead) between cyclodextrins and ligands with a structure similar to bolaform surfactants or surfactants [333,334] have been reported, we focus on systems involving bolaform surfactants.…”

Oligomeric Pseudorotaxanes Adopting Infinite‐Chain Lattice Superstructures

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Polyrotaxanes and polypseudorotaxanes [1] are relatively new types of polymeric materials, comprising polymer chains threaded through cyclic components in the presence or absence, respectively, of bulky stoppers at both ends of their polymeric chains. Cyclodextrins have also been found to crystallize with threaded chains, either of disordered surfactants [8] or of low-molecular-weight polyethylene or polypropylene glycols, which are present in channels created by the stacked cyclodextrin tori running through the crystalline lattices. Crystallinity, if it occurs, is one of the key factors affecting the thermal, optical, mechanical, and chemical properties of polymers, but it is difficult for long polymer chains-typically those in excess of 10 monomer repeating units or those with molecular weights higher than 1000 Dato form macroscopic single crystals, because of both 1) dif-fusion limitations resulting from chain entanglements and 2) the heterogeneous length distributions of most synthetic polymers.

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“…Crystal structures of synthetic polymers are thus usually obtained [4] by computational model-building and diffraction simulation of X-ray powder-or fiber-diffraction data by using structural information from single-crystal analyses of small oligomeric homologues. Cyclodextrins have also been found to crystallize with threaded chains, either of disordered surfactants [8] or of low-molecular-weight polyethylene or polypropylene glycols, which are present in channels created by the stacked cyclodextrin tori running through the crystalline lattices. Cyclodextrins have also been found to crystallize with threaded chains, either of disordered surfactants [8] or of low-molecular-weight polyethylene or polypropylene glycols, which are present in channels created by the stacked cyclodextrin tori running through the crystalline lattices.…”

Polyrotaxane‐Mediated Self‐Assembly of Gold Nanospheres into Fully Reversible Supercrystals

“…In all cases, both host–guest noncovalent interactions and cooperative hydrogen bonds between the macrocycles contribute to the stability of the resulting products 10. In this context, nonionic Igepal (polyoxyethyelene nonyl phenyl ether) surfactants have emerged as excellent candidates to prepare solid structures of self‐assembled polyrotaxanes in the presence of CDs 11a…”