Polyrotaxanes crystalline

Nakajima et al. (1) prepared liquid crystalline polyrotaxane derivatives containing the mesogenic group 4-cyano-4 -hydroxybiphenyl attached to the a-cyclodextrin component of linear polyethylene glycol containing an a-cyclodextrin inclusion complex with an adamantane termini. 

Paraquat, an ionic molecule, is more rigid than polymeric crown ethers. In addition, die crown ether has to adopt a restricted conformation for complexation to occur. The total increase of the rigidity for derived polyrotaxanes 84 depended on the min value [118, 119]. The higher the value of min, the higher Tg of the poly-rotaxane. Paraquat is a crystalline material but the polyrotaxanes are amorphous. 

Physical hydrogels were formed induced by self-assembled water-insoluble and crystalline polypseudorotaxane domains which act as physical crosslinking points. Such physical hydrogels include the polypseudorotaxane systems of a-CD threading on PEO or its copolymers, a-CD threaded on PEI, PL, or their copolymers, and even 3-CD or y-CD threaded PPO or PEI copolymers. The thermo-reversible and thixotropic properties of these supramolecular hydrogels have inspired their applications as injectable drug delivery systems. Physical hydrogels induced by physical interaction of threaded CD molecules in polyrotaxanes were also developed. 

Poly(azomethine)-rofaxa-42-crown-14 p-tri(p-f-butylphenyl) derivatives used as blocking groups liquid crystalline Tm is 67 °C, and smectic between 67 and 73°C. Ti = 123°C. Parent polymer is insoluble polyrotaxane is soluble in chloroform, acetone, etc. [236]... 

D ractograms of polyrotaxanes (Fig. S) indicate a nonuniform arrangement of molecules along the linear polymer chain. Since a definite degree of cyclourethane crystallinity is retained in the structure of the forming polyrotaxane, it ould be assumed that the molecuk has pensions with a higher content of cycles and portions where cycles are absent. This may be schematically represoited as follows ... 

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