title: Switching off the tackiness of a nanocomposite adhesive in 30 s via infrared sintering.
abstract: Soft adhesives require an optimum balance of viscous and elastic properties. Adhesion is poor when the material is either too solidlike or too liquidlike. The ability to switch tack adhesion off at a desired time has many applications, such as in recycling, disassembly of electronics, and painless removal of wound dressings. Here, we describe a new strategy to switch off the tack adhesion in a model nanocomposite adhesive in which temperature is the trigger. The nanocomposite comprises hard methacrylic nanoparticles blended with a colloidal dispersion of soft copolymer particles. At relatively low volume fractions, the nanoparticles (50 nm diameter) accumulate near the film surface, where they pack around the larger soft particles (270 nm). The viscoelasticity of the nanocomposite is adjusted via the nanoparticle concentration. When the nanocomposite is heated above the glass transition temperature of the nanoparticles (T(g) = 130 °C), they sinter together to create a rigid network that raises the elastic modulus at room temperature. The tackiness is switched off. Intense infrared radiation is used to heat the nanocomposites, leading to a fast temperature rise. Tack adhesion is switched off within 30 s in optimized compositions. These one-way switchable adhesives have the potential to be patterned through localized heating.
authors.affiliation: Department of Physics, University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Gurney
authors.forename: Damien
authors.initials: D
authors.lastname: Dupin
authors.forename: Juliana S
authors.initials: JS
authors.lastname: Nunes
authors.forename: Keltoum
authors.initials: K
authors.lastname: Ouzineb
authors.forename: Elodie
authors.initials: E
authors.lastname: Siband
authors.forename: José M
authors.initials: JM
authors.lastname: Asua
authors.forename: Steven P
authors.initials: SP
authors.lastname: Armes
authors.forename: Joseph L
authors.initials: JL
authors.lastname: Keddie