CPM Seminar

The statisstical mechanics to describe the stretching of a single polymer strand (in particular in an AFM experiment) is formulated. As ingredients one needs the potential energy surfaces of the various conformers of the macromolecule. These have been calculated for poly(ethylene glycol) using density functional theory. The resulting force/extension curve (i.e. the mechanical equation of state of the macromolecule) is in quantitative agreement with experiment (without ANY adjustable parameters) for PEG in hexadecane and in water. The interaction of PEG with water is discussed at great length, and also the effect of strong electric fields, in particular a surprisingly large electrostriction. Finally we indicate the directions this first principles approach leads us to develop a theory of polymer brushes.

Thursday, December 14th 2000, 15:30
Ernest Rutherford Physics Building, Board Room (room 104)