Designing pressure sensitive adhesives from brush-like polymer networks

This dissertation reveals how the unique viscoelastic properties of brush-like polymeric networks can be utilized to overcome barriers observed in traditional formulations of pressure sensitive adhesives (PSAs). Two polymer architectures are introduced as universal platforms for their perspective processing mechanisms, UV-cured PSAs and hot-melt PSAs, to control adhesive performance in the absence of migratory additives. Solvent-free UV-cured brush PSAs exhibit unparalleled softness on par with biological tissue which permits spontaneous wetting of the surface roughness of a substrate. However, these materials have limitations in strain-stiffening and strength putting them at risk of cohesive fracture. This adhesion-by-architecture model was advanced to thermoplastic elastomers utilizing A-g-B brush copolymers for hot-melt PSAs (HMPSAs). The extreme softness of brush HMPSAs with independently tunable strength enables near complete replication of tissue elastic and viscoelastic response to deformation. Direct structure-property relationships between network structure and adhesive performance were derived through relaxation dynamics of brush strands for each system. These brush PSAs were further investigated for opportunities in on-demand shifts in mechanical properties and adhesive performance with magnetic stimuli. This work is an important step toward the universal design and AI implementation of PSAs for diverse applications.