Variation with temperature of the thickness of an adsorbed polymer layer in the collapsed state

Abstract

The behaviour of the hydrodynamic thickness LH, below the θ-temperature for the system polystyrene/ trans-decalin, is consistent with the presence of a collapsed adsorbed polymer layer. For three samples of polystyrene (M w ≃ 106 ; Mw = 6 × 105 ; Mw = 4 × 105), one observes a power law dependence LH ∼ (θ-T/T)α with values of α ( — 0.87 ; — 0.83; — 0.80) close to 1.0 rather than to 1/3. These results are consistent with an interdependent macromolecule model. Attempts to obtain a logarithmic factor [ln (T/θ-T)B give values of β between — 0.39 and — 0.65, to be compared with the value — 0.636 obtained theoretically by De Gennes, for a chain surrounded by solvent near the θ-temperature