Ethylene oxide-block-butylene oxide copolymer uptake by silicone hydrogel contact lens materials

► Silicone hydrogel materials were examined following copolymer solution treatments. ► Both surface adsorption and bulk absorption of the copolymer was observed. ► The extent of adsorption and absorption differed greatly between hydrogels. ► Molecular concentration gradient of the copolymer was apparent in all hydrogels. ► The results indicated that the copolymer interaction was material-dependent.