Fabrication of Nickel/Gold Multilayered Shells on Polystyrene Bead Cores by Sequential Electroless Deposition Processes

Abstract

Core-shell conductive beads composed of a polystyrene (PS) core and a metallic shell of nickel-gold were investigated to identify the metal-polymer interface and the electromechanical response under a large deformation. Using dispersion polymerization, the average PS bead diameter was controlled to between 1.5 lm and 4.1 lm by adjusting the water and initiator concentrations, to give a monodispersed particle size distribution. In the electroless deposition processes of Ni followed by gold, the Ni-P shell was initially formed with a thickness of 43 nm, part of which was replaced by gold to give Ni-P and Au shell layers with thicknesses of 39 nm and 43 nm, respectively, as confirmed by transmission electron microscopy (TEM) observation. The electromechanical indentation test of a single core-shell bead showed that its resistance was 9.8 X/bead at a compressive deformation of 35%.

Aperture control in polymer-based composites with hybrid core–shell spheres for frequency-selective electromagnetic interference shielding

“…Shells of nickel and gold were sequentially constructed on PMMA spheres via an electroless deposition method, as reported previously. 13 First, the surface of PMMA microspheres (3 g) was sensitized using tin chloride dihydrate solution (0.1 M). The mixture was stirred for 30 min at room temperature.…”

“…For such purposes, a core–shell-structured polymer sphere is one of the best candidates in a novel composite system, where the mono-sized cores are covered with various EMI shielding materials, such as metal, metal oxide, MXene, carbon nanotube, and graphene. 13–21,40 The distances between the spheres in polymer matrices can be the key factor for controlling the shielding frequency range without the need for varying the thickness, as the aperture size of the composite structure can be precisely controlled by regulating the type and weight fraction of spheres. Thus, the passage of EM waves can be selectively blocked by the specific size of the aperture, which is dictated by the spatial configuration of mono-sized spheres in terms of packing density and particle size.…”

“…Among the candidate materials, nickel/gold multi-shelled polymer spheres, which are widely used in the application of anisotropic conductive films, can be employed to control the aperture in polymeric composites with their well-known high mechanical properties and electrical conductivity originating from the nickel and gold shells, respectively. 13 Also, the graphene or MXene sheets have been easily coated on polymer spheres via electrostatic self-assembly to form segregated composites with the deformability of the polymer cores above the glass transition temperatures. 9,14 If both EM wave-absorbing and reflecting spheres are used in polymer matrices, the contribution of absorption and reflection may be controlled by tuning the ratio of the two fillers.…”

Long-Term Retention of Small, Volatile Molecular Species within Metallic Microcapsules

“…While there are methods available in the existing literature, to apply a metal coating to colloidal objects (mostly solid particles), − the simple three-step method proposed here allows for a full metal coating to efficiently encapsulate small volatile actives in their liquid form. Two other recent articles also report the use liquid core objects to deposit a metal coating. , In the first example, Patchan et al sequentially adsorb multiple layers of polyelectrolyte, followed by tin and palladium ions before the target surface is suitable for metal deposition .…”

Tunable surface metal morphologies and electrical properties of monodispersed polystyrene beads coated with metal multilayers via electroless deposition

“…The polystyrene (PS) beads with a diameter of 4.4 mm and a molecular weight of 36,000 were synthesized using a previously reported procedure [23]. The synthesized PS beads were sulfonated using chlorosulfonic acid, and the ion exchange capacity was measured using an acid-base titration method to give 2.25 meq/g.…”