Microphase Arrangement of Smart Superhydrophilic Segmented Polyurethanes at Their Interface with Water

Abstract

Smart coatings have aroused a growing interest because of the performance of predefined surface functions upon reacting to external stimuli. Among them, responsive polymer coatings to water, which often benefit from the presence of a mobile hydrophilic material, are of great interest. Polyurethanes (PUs) are versatile materials with respect to the structure− property relationship. Therefore, the incorporation of hydrophilic segments in PUs is a rational way to produce water-sensitive smart coatings; however, having a considerable amount of hydrophilic material deteriorates the physical properties because of a large amount of water uptake. In this study, we have analyzed previously synthesized smart PUs, based on hydrophobic polycarbonate (PC) and hydrophilic polyethylene glycol (PEG) soft segments, in which only a limited amount of PEG is used. These coatings maintain, more or less, zero water contact angle, whereas the water uptake remains below 15 wt %. The combination of experimental analysis and coarse-grained molecular dynamics (CG MD) simulations reveals that PEG segments migrate to the coating/water interface and partially cover the surface, whereas the hydrophobic nature of the PC keeps the bulk of the coating intact when the coating is covered with water. Moreover, our CG MD simulations and experimental analysis suggest a reversible phase arrangement under wet/dry cycles on molecular and macroscopic scales.

Effect of Network Topology on the Protein Adsorption Behavior of Hydrophilic Polymeric Coatings

“…We utilized CG MD simulations, dynamic water contact angle, and AFM measurements to analyze the segregation of mPEG dangling chains toward the water layer . We performed a 100 ns simulation of coating/water under constant pressure (1 atm) and temperature (25 °C) and studied the density profile of the mPEG chains in the y direction (normal to the polymer–water interface) as a function of time.…”

“…We utilized CG MD simulations, 42 dynamic water contact angle, and AFM measurements to analyze the segregation of mPEG dangling chains toward the water layer. 55 We performed a 100 ns simulation of coating/water under constant pressure (1 atm) and temperature (25 °C) and studied the density profile of the mPEG chains in the y direction (normal to the polymer−water interface) as a function of time. We integrated the mPEG density profile graph at y > 12.5 nm, where the coating−water interface was located, to quantify the segregation of the dangling chains; the higher integral values show more mPEG chains moving to the water layer.…”

The Martini Model in Materials Science

“…[ 32,55 ] Polymer behavior at interfaces is interesting in many applications among others for coatings or glues. [ 64,98,99 ] For example, Perrin et al. used Martini to study conformations of poly(diallyldimethylammonium) (PDMA) and poly(acrylamide) (PAAm) absorbed to silica surfaces.…”

The Martini Model in Materials Science

“…Polymer behavior at interfaces is interesting in many applications among others for coatings or glues. [76,88,89] For example, Perrin et al used Martini to study conformations of PDMA and PAAm absorbed to silica surfaces. The aim of the study was to investigate why PDMA glues to silica whereas PAAm does not regardless of their very similar chemical structure.…”