An Investigation of the Surface Properties and Phase Behavior of Poly(dimethylsiloxane-b-ethyleneoxide) Multiblock Copolymers

Abstract

Several different multi-block poly(dimethylsiloxane-b-ethyleneoxide) (PDMS-b-PEO) copolymers were synthesized in order to study their phase behavior and surface properties. The surface properties of the PDMS-b-PEO polymers were studied using water contact angle measurements. Their phase behavior was studied by differential scanning calorimetry (DSC). The water contact angle values were measured for cured PDMS-b-PEO copolymer films. The contact angle values were found to change quite dramatically with extended measurement time for the films made of single phase PDMS-b-PEO copolymers. Initially, single phase materials showed similar values to PDMS, but dropped far below the values of PDMS with extended time. This observation indicates the reorientation or migration of PEO segments on the surface, giving an environment responsive character for these materials. In the case where the film was made of phase separated PDMS-b-PEO copolymer, behavior similar to PDMS was found for the whole range of the time measurements. This indicates that the surface of the film was covered with PDMS blocks and the PEO blocks were not able to migrate or reorient to the surface.