Orderly molecular entanglements

Hubin, T.J. and Busch, D.H. (2000) Template routes to interlocked molecular structures and orderly molecular entanglements, Coord. Chem. Rev. 200-202, 5-52. 

Busch. D.H. Ligand design for enhanced molecular organization-selectivity and specific sequencing in multiple receptor ligands, and orderly molecular entanglements. NATO ASI Ser.. Ser. C 1994, 448, 55-80. 

LIGAND DESIGN FOR ENHANCED MOLECULAR ORGANIZATION-SELECTIVITY AND SPECIFIC SEQUENCING IN MULTIPLE RECEPTOR LIGANDS, AND ORDERLY MOLECULAR ENTANGLEMENTS... 

Insulation is effectively achieved if one particular set of interactions is very much stronger than the rest. This is the situation that arises in many coordination polymers (S. R. Batten, R. Robson, Interpenetrating nets ordered, periodic entanglement , Angew. Chem Int. Ed. Engl, 1998, 37, 1469-1494 Angew. Chem, 1998, 110, 1558-1595). But coordination polymers are not molecular in all three dimensions, and as such are not within the scope of this essay. 

Stress relaxation behavior Order-disorder transitions Shear rate dynamic viscosity Molecular entanglement Creep strain... 

Fig. 7 gives an example of such a comparison between a number of different polymer simulations and an experiment. The data contain a variety of Monte Carlo simulations employing different models, molecular dynamics simulations, as well as experimental results for polyethylene. Within the error bars this universal analysis of the diffusion constant is independent of the chemical species, be they simple computer models or real chemical materials. Thus, on this level, the simplified models are the most suitable models for investigating polymer materials. (For polymers with side branches or more complicated monomers, the situation is not that clear cut.) It also shows that the so-called entanglement length or entanglement molecular mass Mg is the universal scaling variable which allows one to compare different polymeric melts in order to interpret their viscoelastic behavior. 

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