Yoshinori Takashima

The development of stimulus-responsive polymeric materials is of great importance, especially for the development of remotely manipulated materials not in direct contact with an actuator. Here we design a photoresponsive supramolecular actuator by integrating host-guest interactions and photoswitching ability in a hydrogel. A photoresponsive supramolecular hydrogel with α-cyclodextrin as a host molecule and an azobenzene derivative as a photoresponsive guest molecule exhibits reversible macrosco

We prepared photoresponsive actuators as both hydrogels and dry gels consisting of 4-arm poly(ethylene glycol) (PEG) cross-linked by a [c2]daisy chain, which is a double-threaded [2]rotaxane dimer with α-cyclodextrin (αCD) and stilbene. The obtained gels showed fast and large deformation triggered by UV irradiation in both wet and dry states. The UV/vis spectroscopy results, NMR measurements and tensile tests on the gels revealed that the actuation is driven by photoisomerization of the stilbene

A series of titanium complexes having tellurium-bridged chelating bis(aryloxo) ligands, [TiX2{2,2‘-Te(4-Me-6-tBu-C6H2O)2}]2 (5: X = Cl; 6: X = OiPr), catalyzed the ring-opening polymerization of cyclic esters such as ε-caprolactone, δ-valerolactone, and l-lactide. The strong dependence of polymerizations on the solvent was observed in this catalytic system. When the polymerizations of ε-caprolactone and l-lactide were carried out in toluene at 100 °C, tellurium-bridged bis(aryloxo)titanium compl

Abstract The copolymers of acrylamide and acrylamide with pendant azobenzene (AzBA–AAm) were prepared by radical polymerization. The association constants of trans-AzBA–AAm copolymers with β-CD are larger than those of cis-AzBA–AAm copolymers. The trans-AzBA–AAm guest copolymer was found to form supramolecular gels with β-CD–pAA (pAA; poly(allylamine)) host copolymers in water.

We prepared acrylamide monomers with permethylated cyclodextrins (PM-CDAAmMe) or peracetylated cyclodextrins (PAc-CDAAmMe). PM-CDAAmMe and PAc-CDAAmMe are soluble in various hydrophobic liquid acrylate monomers, and they can form inclusion complexes with guest monomers such as adamantane or fluoroalkyl groups tethered to a vinyl residue. The bulk polymerization of the liquid acrylate monomers with the PM-CDAAmMe or PAc-CDAAmMe monomers and the guest monomers gave highly flexible and tough elasto

The visualization of changes in the stress and bonding state inside polymeric materials is an attractive function in materials science. In this study, phenolphthalein (PP) was selected to prepare stimuli-responsive coloring materials. PP becomes purple under basic conditions in aqueous solutions; however, PP becomes colorless under basic conditions when it forms a complex with β-cyclodextrin (βCD). To exploit this property of PP, we prepared a color-changing hydrogel (βCD-PP AAm hydrogel) based

Functional polymeric materials constructed by noncovalent bonds have attracted considerable attention due to their beneficial stretching and self-healing properties. We chose host–guest interactions using cyclodextrins (CDs) as host molecules to realize supramolecular materials with stretching and self-healing properties. Notably, an inclusion complex of a CD and a guest molecule functions as a reversible bond in a material. Herein, we studied the relationship between the mechanical properties o

Cyclodextrins were found to initiate ring-opening polymerization of some cyclic esters selectively to give a polyester with a CD at the chain end.

Supramolecular materials based on host-guest interactions should exhibit high selectivity and external stimuli-responsiveness. Among various stimuli, redox and photo stimuli are useful for its wide application. An external stimuli-responsive adhesive system between CD host-gels (CD gels) and guest molecules modified glass substrates (guest Sub) is focused. Here, the selective adhesion between host gels and guest substrates where adhesion depends on molecular complementarity is reported. Initiall

The host-guest interaction as noncovalent bonds can make polymeric materials tough and flexible based on the reversibility property, which is a promising approach to extend the lifetime of polymeric materials. Supramolecular materials with cyclodextrin and adamantane are prepared by mixing host polymers and guest polymers by planetary ball milling. The toughness of the supramolecular materials prepared by ball milling is approximately 2 to 5 times higher than that of supramolecular materials pre

Synthetic polymerases composed of a cyclodextrin (CD) dimer yield high-molecular-weight polymers of cyclic esters without using solvents and co-catalysts. One CD moiety is attached to the active site of a supramolecular catalyst and propagates the polymerization by serving as artificial molecular clamp (see picture). The other CD moiety initiates the ring-opening polymerization. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-