Liquid marble containing degradable polyperoxides for adhesion force-changeable pressure-sensitive adhesives†
Liquid marbles containing a sticky polyperoxide were prepared by the in situ copolymerization of the 1,3-diene monomer with oxygen. The as-prepared liquid marbles had a non-sticky nature and could move on any substrates due to the presence of hard particles on their surfaces, while the squeezed liquid marble developed adhesion force-tunable PSA properties due to the outflow of the inner materials. The 180° peel strength of the squeezed liquid marble increased by heating at 90 °C for 1 h or by UV irradiation at 0.86 J cm−2 because the cohesive force of the adhesive layer increased by the additional polymerization initiated by moderate decomposition of the polyperoxide. The increased 180° peel strengths were significantly decreased again to almost zero, i.e., dismantling, after an additional heating at 150 °C for 1 h because of an excess increase in the cohesive force as pressure-sensitive adhesives, where cross-linking took place as a result of significant decomposition of the polyperoxide accompanied by hydrogen abstraction and coupling.