| Abstract
| - ζ potential measurements were used to determine the adsorbed layer thickness of poly(ethylene oxide)−polypropylene oxide−poly(ethylene oxide) (PEO−PPO−PEO) block copolymers at the surfaces of poly(dimethylsiloxane) emulsion droplets, silica particles, and polystyrene latex particles. The adsorbed layerthickness (δ) was shown to depend on the copolymer structure, the surface chemistry of the adsorbent,and the level of cross-linking within droplets. For a wide range of copolymers, δ values are in the range2−20 nm and directly proportional to the PEO block length. For copolymers with PEO segment lengths> PPO segment lengths, the plateau δ values for PDMS, latex, and silica correspond to ∼35%, 20%, and7% of the fully extended PEO segment length. Equivalent values for copolymers with PEO segment lengths< PPO segment lengths are significantly greater but follow the same dependence on the type of adsorbent.As the level of internal cross-linking within the PDMS droplets was increased, the interface became lessdeformable and the adsorbed copolymer layer thickness significantly decreased. Findings are discussedwith respect to the adsorbed copolymer conformations, which result from different adsorption mechanismsand the influence of interfacial penetrability.
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