Irreversible adsorption from concentrated polymer solutions

Loïc Auvray , Margerida Cruz , Philippe Auroy

We study the adsorption of concentrated Poly(dimethylsiloxane) (PDMS) solutions in Dichloromethane on porous silica. We vary the plymerization index N and the chain volume fraction Φ from the overlap concentration to the melt. The adsorption of PDMS on silica by hydrogen bonding is very strong and a large amount of polymer remains bound to the surface after the washing of the silica with a good solvent of the chains. We measure this quantity Γ by small angle neutron scattering. If there is no chain desorption, Γ represents the weight of polymer attached to the solid in the initial solution, which varies as the product N1/2 Φ7/8 according to a recent prediction. This relation of proportionality indeed interprets our experimental results. When the size of the chains is comparable to the pore diameter (either 500, 1 200, or 3 000 Å  depending on the samples) we observe confinement effects which lower the adsorbed amount.

Domaines: Articles anciens

Loïc Auvray, Margerida Cruz, Philippe Auroy. Irreversible adsorption from concentrated polymer solutions. Journal de Physique II, 1992, 2 (5), pp.1133-1140. ⟨10.1051/jp2:1992191⟩. ⟨jpa-00247697⟩