Piston-rotaxanes as molecular shock absorbers.
We describe the thermomechanical response of a new molecular system that behaves as a shock absorber. The system consists of a rodlike rotaxane connected to a piston and tethered to a surface. The response of this system is dominated by the translational entropy of the rotaxane rings and can be calculated exactly. The force laws are contrasted with those for a rigid rod and a polymer. In some cases, the rotaxanes undergo a sudden transition to a tilted state when compressed. These piston-rotaxanes provide a potential motif for the design of a new class of materials with a novel thermomechanical response.
Research School of Chemistry, Australian National University, Canberra 0200 ACT, Australia. sevick@rsc.anu.edu.au
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Sevick
D R M
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Williams