Peculiar Nonlinear Elasticity of Polyrotaxane Gels with Movable Cross-Links Revealed by Multiaxial Stretching
(8661–8667) Macromolecules 44 #21 (2011)
Bitoh et al , Japan, showed a peculiar rubber elasticity feature of polyrotaxane (PR) gels with cross-links capable of moving along network strands by general biaxial strain testing that varies the strains in the two orthogonal directions.  The influence of the strain in one direction on the stress in the other direction in the PR gels with sufficiently low cross-link concentrations is much smaller than that in conventional elastomers and gels with fixed cross-links.  The stress–strain behavior of the PR gels under various types of deformation is exceptionally close to the prediction of the neo-Hookean model with no explicit strain-coupling between the different principal directions other than that resulting from volume conservation.  The minimal strain-coupling between different two directions is a pronounced feature for PR gels with movable cross-links to vary the network topology in response to imposed deformation.  (RDC 11/3/2011)

Stable and Unconventional Conformation of Single PEG Bent γ-CD-Based Polypseudorotaxanes
(2319–2327)  Macromolecular Chemistry and Physics 212 #21 (2011)
Gao et al of the Beijing Institute of Technology, China, found the unexpected formation of polypseudorotaxanes via attaching 2-bromoisobutyryl groups to both ends of poly(ethylene glycol) (PEG), which leads to the self-assembly with γ-cyclodextrins in aqueous solution.  The resulting polypseudorotaxanes show stable and unconventional single PEG bent conformations.  These polypseudorotaxane products are so stable that they can initiate the bulk ATRP of butyl methacrylate to give rise to the same conformational polypseudorotaxanes.  (RDC 11/3/2011)

Construction of Polypseudorotaxane from Low-Molecular Weight Monomers via Dual Noncovalent Interactions
(4092–4097) Macromolecules 44 #11 (2011)
Zhu  et al of the East China University of Science & Technology, China, synthesized three low-molecular weight compounds for supramolecular polymerizations and attempted to employ the metal–ligand interaction between the pyridine nitrogen and Pd (II), for cooperating with the host–guest binding between azobenzene and β-cyclodextrin (β-CD), to complete the end-to-end connection of the polymer chains.  Routes for stepwise introduction of two of the self-assembly behaviors as well as a one-pot preparation were investigated by 1H NMR and 2D nuclear Overhauser enhancement spectroscopy (NOESY) 1H NMR spectroscopy. The self-assembly strategies based on the full orthogonality of both noncovalent interactions will allow for a smart and rapid synthesis of precise structural controlled supramolecular polymeric assemblies such as polypseudorotaxanes via noncovalent interactions from low-molecular weight monomers  (RDC 6/19/2011)

The static structure of polyrotaxane in solution investigated by contrast variation small-angle neutron scattering
(155-163) Polymer Journal 43 #2 (2011)
Endo et al of the University of Tokyo, Japan, studied the static structure of polyrotaxane (PR) dissolved in a good solvent using contrast variation small-angle neutron scattering. The decomposed partial scattering functions of the cyclic molecules and the axial polymer and the cross-correlation between cyclic molecules and an axial polymer strongly supported the idea that the alignment of cyclic molecules threaded on the axial polymer is random.  On the basis of experimental observation, the entropic origin of the stiffening of PR due to the array of cyclic molecules is discussed.  (RDC 6/8/2011)

Cucurbit[7]uril moving on side chains of polypseudorotaxanes: Synthesis, characterization, and properties
(2138–2146) Journal of Polymer Science Part A: Polymer  Chemistry 49 #10 (2011)
Yang, Hao and Tan of Shandong University, China, synthesized side chain polypseudorotaxanes with cucurbit[7]uril (CB[7]) threaded onto the side chains from a water-soluble polymer and CB[7] in water by simple stirring at room temperature.  CB[7] beads could move from the hexyl groups to the benzyl and a part of viologen units in the side chains of polymer when the molar ratio of CB[7] to the monomer reaches from 1 to 2 as shown by 1H NMR studies, and it is considered that the hydrophobic and charge-dipole interactions of CB[7] are the driving forces.  The sizes of the polypseudorotaxanes with different molar ratio of CB[7] to 4VBVHeP in aqueous solution increase with increasing the molar ratio of CB[7] to 4VBVHeP as found by DLS and resonance light scattering, while the typical cyclic voltammograms and UV–vis data indicate that CB[7] are not threaded in the viologen units of P4VBVHeP, and the oxidation reduction characteristic of the polymer is remarkably affected by the addition of CB[7]. (RDC 4/4/2011)

Formation and Characterization of Inclusion Complexes of Alkyne Functionalized Poly(ε-caprolactone) with β-Cyclodextrin. Pseudo-Polyrotaxane-Based Supramolecular Organogels.
(375–382) Macromolecules 44 #2 (2011)
Jazkewitsch and Ritter of the Heinrich-Heine-University Duesseldorf, Germany used β-Cyclodextrin to form pseudo-polyrotaxanes with propargyl functionalized poly(ε-caprolactone) in N,N-dimethylformamide.  Furthermore, supramolecular organogels based on the pseudo-polyratoxanes (PPR) were synthesized via 1,3-dipolar cycloaddition of propargyl functionalized poly(ε-caprolactone) and mono-(6-azido-6-desoxy)-β-cyclodextrin. (RDC 1/19/2011)

A Versatile Synthesis of Diverse Polyrotaxanes With a Dual Role of Cyclodextrin as Both the Cyclic and Capping Components
(8799–8804) Macromolecules 43 #21 (2010)
Kato, Komatsu,and Ito of the University of Tokyo developed a synthesis based on transesterification with excess cyclodextrin at both ends of pseudopolyrotaxanes activated with p-nitrophenyl ester. (RDC 11/6/2010)

A Versatile Synthesis of Diverse Polyrotaxanes with a Dual Role of Cyclodextrin as both the Cyclic and Capping Components
(8799–8804) Macromolecules 43 #21 (2010)
Kato, Komatsu and Ito of the University of Tokyo developed a synthesis based on transesterification with excess cyclodextrin at both ends of pseudopolyrotaxanes activated with p-nitrophenyl ester. (RDC 11/6/2010)