Pressure-Sensitive Adhesives with Tunable Tackiness

Abstract

The adhesive properties of pressure-sensitive adhesives based on interpolymer complexes of poly(vinyl caprolactam) and poly(N-isopropylacrylamide) with oligo(ethylene glycol) are studied. Poly(N-isopropylacrylamide) and poly(vinyl caprolactam) in such hydrogen-bonded complexes retain phase-separation ability in the presence of water at elevated temperatures which makes it possible to obtain adhesives that reversibly lose stickiness when heated. Analysis of the wettability of the surface of poly(vinyl caprolactam)–oligo(ethylene glycol) and poly(N-isopropylacrylamide)–oligo(ethylene glycol) films proves that tackiness is lost due to the hydrophobization of their surface during the phase transition. The switching temperature of the adhesives depends on their content of water. However, for dry compositions adhesion considerably decreases near the lower critical solution temperature.