Dynamics of amphiphilic diblock copolymers at the air-water interface

Antonio Stocco (1) , Klaus Tauer (1) , Stergios Pispas (2) , Reinhard Sigel (3)

1 Max Planck Institute of Colloids and Interfaces
2 Theoretical and Physical Chemistry Institute,
3 Adolphe Adolphe Merkle Institute

Two polyisoprene-polyethyleneoxide diblock copolymers with different block length ratios adsorbed to the water surface were investigated by multiple angle of incidence ellipsometry, evanescent wave light scattering, and surface tension experiments. In a semidilute interfacial regime, the transition from a two-dimensional to a "mushroom" regime, in which polymer chains form loops and tails in the subphase, was discussed. A diffusion mechanism parallel to the interface was probed by evanescent wave dynamic light scattering. At intermediate concentrations, the interfacial diffusion coefficient D∥ scales with the surface concentration Γ, as D∥ ∼ Γ0.77 in agreement with the scaling observed for polymer solutions in a semidilute regime. At relatively high concentrations a decreasing of D∥ is discussed in terms of increasing friction due to interactions between polyisoprene chains.

Domaines: Matière Molle [cond-mat.soft]

Antonio Stocco, Klaus Tauer, Stergios Pispas, Reinhard Sigel. Dynamics of amphiphilic diblock copolymers at the air-water interface. Journal of Colloid and Interface Science, 2011, 355 (1), pp.172-178. ⟨hal-00786309⟩