Patrick J. Colver

Multilayered Nanocomposite Polymer Colloids Using Emulsion Polymerization Stabilized by Solid Particles

We report a versatile emulsion polymerization process in which solid nanoparticles are used as stabilizer, thereby replacing the role of surfactants, allowing for simple fabrication of armored nanocomposite polymer latexes. Use of a second conventional seeded emulsion polymerization step provides a straightforward route to more complex multilayered nanocomposite polymer colloids.

Colloidosomes as micron-sized polymerisation vessels to create supracolloidal interpenetrating polymer network reinforced capsules

Supracolloidal interpenetrating polymer network reinforced capsules are prepared by using micron-sized colloidosomes of poly(methyl methacrylate--divinylbenzene) microgels as reaction vessels. An interpenetrating polymer network as scaffold is generated radical polymerisation of the interior phase to produce hollow supracolloidal structures with a raspberry core-shell morphology. Their flexibility is tailored by variation of the monomer feed composition.

Soft polymer and nano-clay supracolloidal particles in adhesives: synergistic effects on mechanical properties

Numerous synthesis routes toward nanostructured polymer particles have emerged, but few examples demonstrate the essential need for such complex particle structures to achieve any added benefit in a target application. Here, polymer particles having Laponite clay armor were prepared by the Pickering miniemulsion polymerization of n-lauryl acrylate. The resulting “soft–hard” poly(lauryl acrylate) (PLA)–Laponite hybrid particles were blended at various low concentrations with a standard poly(butyl acrylate-co-acrylic acid) (PBA) latex for application as a waterborne pressure-sensitive adhesive (PSA). The tack adhesion properties of the resulting nanocomposite films were compared with the performance of the PBA when blended with either a conventional non-armored PLA latex, with Laponite RD nanosized clay discs, or a mixture of both. A true synergistic effect was discovered showing that the clay-armored supracolloidal structure of the hybrid particles was essential to achieve a superior balance of viscoelastic properties. The addition of small amounts, e.g. 2.7 wt%, of the “soft–hard” clay-armored PLA particles increased the tack adhesion energy considerably more than found for the two individual components or for the sum of their individual contributions. The soft PLA core ensures that the adhesives are not stiffened too much by the nanosized Laponite clay. Slippage at the interface between the nanoclay platelets and the PBA matrix introduces an additional energy dissipation mechanism during deformation. Through the synergistic effect of the clay and PLA in the supracolloidal armored latex structure, the tack adhesion energy is increased by 45 J m−2, which is about 70% greater than found for the PBA adhesive alone.