SUPRAMOLECULAR CONTROL OF MECHANICAL PROPERTIES IN SINGLE MOLECULES, INTERFACES, AND MACROSCOPIC MATERIALS

SUPRAMOLECULAR CONTROL OF MECHANICAL PROPERTIES IN SINGLE MOLECULES, INTERFACES, AND MACROSCOPIC MATERIALS 

DAVID M. LOVELESS, FARRELL R. KERSEY, and STEPHEN L CRAIG 

Dramatic examples have also been reported for main-chain supramolecular polymers (SPs Lehn 1993 Ciferri 2005 Fig. 3.1), in which specific and directional molecular recognition events between end groups define the main chain of a linear polymeric assembly. Although main-chain SPs had been created and characterized previously (Broze et al. 1983 Fouquey et al. 1990 Alexander et al. 1993 Bladon and Griffin 1993 St Pourcain and Griffin 1995), it was a groundbreaking paper in 1997 that demonstrated the mechanical potential of supramolecular interactions and catalyzed much of the current interest in the field (Sijbesma et al. 1997). 

Molecular Recognition and Polymers Control of Polymer Structure and Self-Assembly. Edited by V. RoteUo and S. Thayumanavan Copyright 2008 John Wiley Sons, Inc. 

As we consider the mechanical properties of SPs, it is often useful to consider them in the context of entanglements, which are intermolecular interactions that transfer mechanical forces from one molecule to the next. In this chapter we use the term entanglement in a very general way, so that it includes topological entanglements (one polymer chain is physically wrapped around another), chemical entanglements (attractive intermolecular interactions between polymer chains), and surface adsorption (attractive intermolecular interactions between polymer chains and a particle surface, e.g., from a filler). The important, fundamental characteristic is that it is an interaction that allows a mechanical stress on one molecule to be distributed or transferred to another molecule with which it is entangled. 

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