Wetting Behavior of Graft Copolymer Substrate with Chemically Identical Homopolymer Films

Abstract

The wetting behavior of deuterated poly(ethyl acrylate) (dPEA) and polystyrene (PS) homopolymers on the substrates of dPEA-PS graft copolymers with different graft chains (dPEA-g-xPS, x ) 1, 3, 5, average number of graft chains) was investigated utilizing scanning force microscopy (SFM). The lateral force and adhesion force measurements of dPEA-g-xPS substrates show that the surface molecular mobility of the dPEA-g-xPS substrate with the dPEA outermost layer decreases with the number of graft chains because of their different aggregation structure. As the number of PS grafts increases, the wetting behavior of dPEA on graft copolymer substrates changes from wetting to partially wetting. The contact angle measurement at the dPEA homopolymer/dPEA-g-xPS substrate interface indicates that the substrate with more PS grafts has a higher interfacial tension with the dPEA homopolymer. The wetting behavior of PS homopolymer on the dPEA-g-xPS substrates depends on the viscosity of the substrate, which is expected to be lower than that of the PS homopolymer. The dewetting velocities of the PS homopolymer increase with the increase of PS grafts in the dPEA-g-xPS graft copolymers.

Evaluation of compatibility in SAN/EPDM blends by determination of the adhesion parameters

“…Also, higher value of work of adhesion of some polymer pairs (SAN/EPDM-g-PS and EPDM/EPDM-g-PS) in comparison to neat SAN/EPDM blend indicate stronger interaction between SAN, EPDM, and compatibilizer at the interface. Value of wetting coefficient (S c/m , S m/c ) has to be positive and minimal in order to enhance good adhesion between two phases in the blend [28] and value of work of adhesion tends to be maximal. From the obtained results, the positive values of wetting coefficient S c/m of components pair EPDM/g-3T and S m/c of SAN/g-3T mean possibility of encapsulation of EPDM phase with compatibilizer and embedding of compatibilizer at the interface of SAN/ EPDM blends.…”

Glass Transition Behavior of PS Films on Grafted PS Substrates

“…Free polymer chains in contact with the grafted (or brush) polymer layer can show either wetting or dewetting (or segregation) behavior depending on the ratio of molecular weights of the matrix component to grafted polymer chains and the grafting densities of the brush component. [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56] For polymer chains on the brushes of the same chemical identity, this behavior (termed "autophobic dewetting") can be attributed to the entropic effects of the matrix polymer and the grafted polymer chains. [40][41][42][43][44][47][48][49][50][51][52][53][54][55][56] More recently, we have investigated the dewetting behavior of a polymer matrix of different chemical identity on the brush substrates.…”

“…[39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56] For polymer chains on the brushes of the same chemical identity, this behavior (termed "autophobic dewetting") can be attributed to the entropic effects of the matrix polymer and the grafted polymer chains. [40][41][42][43][44][47][48][49][50][51][52][53][54][55][56] More recently, we have investigated the dewetting behavior of a polymer matrix of different chemical identity on the brush substrates. Specifically, we studied the dewetting behavior of PMMA melts on grafted PS layers as a function of brush thickness (or grafting density), 57 and found, in agreement with theoretical calculations, that the behavior of this pair of chemically distinct melts was qualitatively similar to that expected for autophobic dewetting behavior.…”

Surface modification of gold nanoparticles with polyhedral oligomeric silsesquioxane and incorporation within polymer matrices

“…However, if the number of grafts POSS in backbone of the random copolymer is increased, the increased unfavorable entropy quickly overcomes the enthalpy gain and the interfacial tension is actually increased, and thus induces more phase segregation. 31,32 Wide-angle X-ray diffraction (WAXD) analyses were preformed to quantify the d-spacing of polymer chains when Au-POSS was incorporated. 33 Figure 6 shows WAXD patterns of the PnBMA-r-PiBPPMA random copolymer containing different contents of Au-POSS nanoparticles.…”