Effect of PEO Grafts on the Surface Properties of PEO-Grafted PU/PS IPNs:  AFM Study

Abstract

The change of the interfacial phenomena of muticomponent polymeric systems based on self-reorganization is very important for many applications of them. Specially, when they are used for biomedical application, the change of surface properties in water is a key factor because they are mostly used in the aqueous environment of the human body. An interpenetrating polymer network (IPN) is a mixture of network polymers. The morphology of an IPN can be controlled to obtain materials with nanoscale domains, and the morphology once formed is permanent due to the presence of the physical interlocking between the networks. In this study, surface compositional mapping was attempted with atomic force microscopy (AFM) images of poly(ethylene oxide)-grafted polyurethane/polystyrene IPNs (PEO-grafted PU/PS IPNs) to investigate the structural change under water, and the effect of hydrophilic PEO pendant chains on the change of local elasticity and surface energy of the IPN under water was studied by using the "force-distance (F/D) analysis" of AFM. The compositional mapping in water showed that the area fraction of the hydrophilic PU-rich phase was increased by PEO grafting, but the structural reorganization did not occur. From the result of F/D analysis in water, the mobile and flexible pendant PEO chains increased the surface elasticity and softness of PU/PS IPNs. The crystallinity also affected the surface hardness of the dried PEO-grafted PU, but it did not when the samples were swollen in water.

Tracking the hydrophobicity recovery of PDMS compounds using the adhesive force determined by AFM force distance measurements

“…Similar studies have been performed by Kim et al [13], who determined the surface hydrophilicity of polyurethane/ polystyrene in a hydrophobic poly(ethylene oxide) matrix with force distance measurements, and by Jarvis and Pethica [24], who compared different hydrophobic modifying layers by measuring force curves.…”

“…The oxidized surface is then covered by these siloxanes [10][11][12] but re-orientates to its original state with time [7,13]. Urban and Stewart [14] found that highly mobile short chains of silicone elastomers are formed in the high-energy plasma environment, and that these low molar mass oligomers are responsible for the recovery of the hydrophobicity.…”

Preparation and characterization of low-temperature hydrogenated nitrile butadiene rubber hybrid with hydrogen bonds for the sealing applications

“…Some nano-scale micro-phase (brighter color) is scattered in the continuous phase (darker color) for the hybrid. It has been reported that color shading in AFM phase diagram has relation to softness of each phase [28]. This means that the brighter area belongs to rigid phase (i.e.…”

“…This is the main reason why high tan d values display in our hybrids whereas their tan d max values always decrease when common fillers are added. In addition, due to the nanoscale phase domain of dispersed AO-80, the hybrid is rather than miscible system (a single peak of tan d-T curve) as described in some copolymer or IPN polymer [28]. Fig.…”

Preparation and characterization of polysiloxane‐acrylate latexes with MPS‐PDMS oligomer as macromonomer

“…More recently, the spectrum of AFM applications to polymers has been broadened substantially from relatively simple visualizations of morphology to more advanced examinations of polymer structure and properties on a nanometer scale due to the discovery of new AFM capabilities. [32][33][34] Figures 8 and 9 showed the AFM images of PDMS-Poylacrylate polymer membrane (PDMS-15 and PDMS-50). The left area of these figures exhibited the roughness of the membranes, the brighter phase was the phase with higher position and the darker phase was the phase with lower position; the right area exhibited the difference of modulus of the membranes, the brighter phase was the phase with higher modulus and the darker phase was the phase with lower modulus.…”