Lm. Dai et al., CONFORMATIONAL TRANSITIONS OF END-ADSORBED COPOLYMER CHAINS AT THE LIQUID SOLID INTERFACE/, Macromolecules, 28(16), 1995, pp. 5512-5517
Using the surface force apparatus, the conformational rearrangements o
f end-adsorbed diblock and triblock copolymer chains at the liquid/sol
id interface have been investigated. While the end-adsorbed poly(ethyl
ene oxide)-polystyrene, PEO-PS, diblock copolymer ''blushes'' at a tol
uene/mica interface were seen to collapse upon the replacement of tolu
ene by cyclohexane, rapid conformational transitions between ''loops''
and ''tails'' were observed for the end-adsorbed (2-vinylpridine)-pol
ystyrene-poly(2-vinylpridine), PVP-PS-PVP, triblock copolymer chains a
t the toluene/mica interface during compression- decompression cycles.
It was demonstrated for the first time that the newly formed tail-lik
e triblock copolymer chains could be mechanically stretched beyond the
ir equilibrium dimensions, a process which to some extent can be descr
ibed by Rabin and Alexander's scaling model. The dynamics of the confo
rmational rearrangements was followed by surface force measurements at
the molecular level.