In Silico study of hydrogel adhesives

Adhesion is defined as the process of joining two dissimilar surfaces together so that they can resist separation. Adhesives can be in various physical forms including liquid, film, powder etc. In the last three decades, adhesives and adhesion phenomena in biomedical applications have been the subject of intensive studies and rapid developments, because of their significance in many scenarios, e.g., wound dressing and implant installations. Due to the wet and corrosive environment of human fluids, achieving good adhesion while maintaining good biocompatibility is never an easy task. Usually bioadhesives are in the form of polymeric glue or patch. Besides, taking inspirations from nanoparticle incorporated in polymer network to enhance composites' mechanical properties, solutions of nanoparticles have recently been introduced as a new type of bioadhesive. Robust bioadhesives already exist, and some of them are commercialised for clinical use. However, they are far from ideal. Each type of currently available bioadhesive has its own limitations. In most cases, the microscopic mechanism of adhesion and the adhesive behaviour during mechanical deformation is still unclear. Thanks to the rapidly developing computational powers of modern computers, more and more simulation work can now be used to understand how these mechanisms can lead to more robust performance, aiming at further improvement. By using a molecular simulation approach, I have investigated both polymer and nanoparticle based adhesive to glue hydrogels, carrying out parametric studies and optimisations. In particular, after discussing the literature on adhesion in Chapter 1 and the general methodology in Chapter 2, in Chapter 3 I study polymer based glues for hydrogels, looking at how their architecture affects their gluing power. In Chapter 4, I switch to adhesive patches, where polymer chains are not in solutions but rather grafted onto a crosslinked polymer matrix, and look at the effect on adhesion of both chains and the matrix structure, as well as their interactions with the hydrogel. In Chapter 5, I address the case of nanoparticle based glues, looking at how their size, shape and their mutual interactions and their interactions with the gel, affect their overall adhesive behaviours. Finally, in Chapter 6, I summarise all previous work, and provide potential directions for future work based on the results obtained so far.Open Acces