Large-Area Patterning of the Tackiness of a Nanocomposite Adhesive by Sintering of Nanoparticles under IR Radiation

Abstract

We present a simple technique to switch off the tack adhesion in selected areas of a colloidal nanocomposite adhesive. It is made from a blend of soft colloidal polymer particles and hard copolymer nanoparticles. In regions that are exposed to IR radiation through a mask, the nanoparticles sinter together to form a percolating skeleton, which hardens and stiffens the adhesive. The tack adhesion is lost locally. Masks can be made from silicone-coated disks, such as coins. Adhesive island regions are defined with the surrounding regions being a non-tacky coating. When optimizing the nanocomposite's adhesive properties, the addition of the hard nanoparticles raises the elastic modulus of the adhesive significantly, but adhesion is not lost because the yield point remains relatively low. During probe-tack testing, the soft polymer

Stratification in binary colloidal polymer films: experiment and simulations

“…Colloidal particles can be cast from suspensions to make a coating or film on a substrate. Colloidal films have a wide variety of applications, including inks, 1 cosmetics, 2 pharmaceutical encapsulation, 3,4 active ingredient binders, 5,6 adhesives, 7,8 and paints. 9,10 Waterborne colloidal polymer particles, commonly known as latex, are attractive because they form dry films with only a small (or no) release of volatile organic compounds (VOCs) into the environment, 11 whereas their solvent-cast analogues are polluting to the atmosphere.…”

Power Density Threshold for Switching Off the Tack Adhesion of Colloidal Nanocomposites

“…The P2 latex synthesis included the use of a chain transfer agent to reduce the mean molecular weight so as to impart more liquid‐like properties to the adhesive matrix. The latex (P2) and NPs were synthesized by emulsion polymerization by methods described elsewhere . The mean hydrodynamic diameters of the dispersed particles were determined by dynamic light scattering (photon correlation spectroscopy) using a Delsa Nano‐C particle sizer (Beckman Coulter).…”

“…The latex (P2) and NPs were synthesized by emulsion polymerization by methods described elsewhere. [ 19 ] The mean hydrodynamic diameters of the dispersed particles were determined by dynamic light scattering (photon correlation spectroscopy) using a Delsa Nano-C particle sizer (Beckman Coulter). Prior to the measurement, an aliquot of the aqueous dispersion was diluted in the range from 0.05 to 1 w/w% using distilled deionized water (Milli-Q, 18 MΩ).…”

“…The use of a mask for IR light to heat the nanocomposites switched the adhesion off only in the unmasked regions . Thus, the nanocomposite adhesives were patterned via a simple process.…”

“…The use of a mask for IR light to heat the nanocomposites switched the adhesion off only in the unmasked regions. [ 19 ] Thus, the nanocomposite adhesives were patterned via a simple process. In this initial work developing these responsive materials, the hard NPs were made from poly(methyl methacrylate) copolymers having a T g of 100 °C.…”