Cracking polymer coatings of paper-like surfaces: Control via block co-polymer structure and system composition

Dissipative particle dynamics simulations are employed to examine the self-assembly of a three-component polymeric coating on a hydrophilic surface. The examined suspension is composed of an amphiphilic di-block co-polymer, a hydrophobic polymer, and a hydrophilic stabilizer in water. For technological relevance, the basis hydrophobic and hydrophilic polymer contents correspond to poly(styrene-co-n-butyl acrylate) and to starch, respectively, while the hydrophilic surface resembles unmodified cellulose. We show that the amphiphilic di-block co-polymer is key in controlling the assembling coating structure: symmetric co-polymers form well-ordered lamellar coatings, while asymmetric ones lead to advanced patterning in the film. This response persists over a broad composition range of additional hydrophobic material. We also map the sensitivity of the results to polymer chemistry by variation of the interaction parameters. Finally, we show that the presence of excess free stabilizer in the coating solution can disrupt the homogeneity of the film, potentially deteriorating coating quality in practical applications. The findings stress the importance of block compositions and component concentrations as fundamental means to tune surface coating films and their internal structure.