Computational modelling of block copolymer surface coatings at multiple length scales

Block copolymer films are a promising class of materials for surface coatings and thin-filmtechnologies. Their ability to self-assemble into ordered nanostructures makes them highly versatilefor a wide range of applications, from protective and barrier layers to membranes andnanolithography. One particularly important application is producing moisture preventing films,where the characteristics of the polymeric films directly affect their effectiveness and durability. This doctoral thesis explores how such coatings form and resist water penetration at the molecularlevel. The work focuses on understanding how the chemical structure of the copolymer chains andthe composition of the coating mixture influence the resulting film structure and its performanceagainst water penetration. To achieve this, two complementary computational approaches wereused. Coarse-grained dissipative particle dynamics simulations capture how block copolymer chainsself-assemble into film structures, and atomistic detail molecular dynamics modelling examineswater interactions at the molecular scale. Together, these methods provided a multiscale view of thecoating formation process and the resulting barrier properties. The results show that the balance between the hydrophilic and hydrophobic parts of the amphiphilicblock copolymer, used to produce the protective coatings, plays an important role in determining thecoating formation on a surface. Copolymer chains with nearly symmetric hydrophobic-hydrophilicblock architecture form continuous layers that can act as effective barriers, while asymmetriccopolymer chains produce patchy, defective coating structures. The relative amount of eachcomponent in the coating mixture was also found to be important: too little or too much of onecomponent leads to structural imperfections. In addition to the barrier performance of the coating, the chemical nature of the hydrophobic part ofthe copolymer was found to determine how well the coating retains its structure when exposed tostrain. Several copolymers were examined by simulations to extract guidelines for maintaining highbarrier performance and limiting water penetration even under strain. The findings offer crucialknowledge for the real-world usage of such coatings. Overall, this thesis clarified the relationships between the molecular structure of the blockcopolymers, coating morphology, and their water penetration performance. The insights gainedestablish principles that can guide a rational design of moisture-barrier coatings for applications,e.g., in packaging and other surface protection technologies.