Synthesis and Structure of Macromolecular Topological Compounds

α-Cyclodextrin/Polyethylene Glycol Polyrotaxane: A Study of the Threading Process

“…Harada showed that the threading process rate depends on the PEG chain length, reaching a maximum when the linear polyethylene glycol molecule has a molecular weight of about 3000. 10 In order to explain our experimental data and the findings reported by the literature 10 regarding the effect of the PEG chain length on the threading process, we propose a model at the microscopic level that takes into account five different steps in which the whole phenomenon can be divided: (1) (1) When R-CD and PEG are dissolved in the solvent, they will randomly move by diffusion. Some of the R-CD molecules will be located in the proper position for the entrance of the PEG end into their free cavity.…”

“…Polyrotaxanes belong to a new topological set of molecules and the study of their structure and properties has begun only recently. 1,2 These interesting compounds are usually made up of one or more cyclic molecules threaded around a linear chain that penetrates their empty cavities. The production of a polyrotaxane is driven by noncovalent attractive forces 3 that are responsible for the formation of highly organized biological systems such as membranes, ribosomes, and enzyme complexes from relatively simple subunits.…”

Polymeric Rotaxanes

“…Although the reactions of the complexes of amines with cyclodextrin (CD) and those of carboxylic acids, and formation of polyrotaxanes using cyclic urethanes during polymerization were reported, − CDs were found to thread onto a polymer chain to give polyrotaxanes for the first time in 1990 …”

Noncovalent Cross-Linking of Poly(methyl methacrylate) via Polypseudorotaxane

“…The first step is to prepare a polypseudorotaxane as a prepolymer by free radical polymerization of a vinyl monomer in the presence of a large ring molecule. Polypseudorotaxanes represent a new class of macromolecular architectures in which macrocycles are penetrated by linear polymers and thus the two components are mechanically linked with each other. – Threading can occur during polymerization in the presence of a macrocycle. – The second step corresponds to the conversion of the polypseudorotaxane to noncovalent cross-linked structure by solid-state fixation of the linear chain with rings (both threaded and free). Since polypseudorotaxanes are tractable precursor polymers, it is possible to obtain cross-linked polymers with desired shapes.…”

“…[18][19][20][21][22] Threading can occur during polymerization in the presence of a macrocycle. [23][24][25][26] The second step corresponds to the conversion of the polypseudorotaxane to noncovalent cross-linked structure by solid-state fixation of the linear chain with rings (both threaded and free). Since polypseudorotaxanes are tractable precursor polymers, it is possible to obtain cross-linked polymers with desired shapes.…”