Metal-Coated Microspheres
Metal‑coated polymer particles are essential materials in a wide range of high‑tech applications, including catalysis, anisotropically conductive adhesives (ACAs), microelectronics, Surface Enhanced Raman Scattering (SERS), Particle Image Velocimetry (PIV), and bioassays. As a leading specialist in monodisperse microspheres, microParticles GmbH offers highly uniform polymer particles with precision metal coatings tailored to demanding research and industrial environments.
Over recent years, our scientists have developed robust and versatile metallization strategies suitable for various polymer substrates such as melamine resins, polystyrene, poly(styrene‑divinylbenzene), PMMA, and silica. These composite microspheres feature a monodisperse polymer core with either metal nanoparticles or continuous metallic shells made from gold, silver, copper, and other metals.
Coating techniques:
Self-organization: Adsorption of preformed metal nanoparticle
- In this method, preformed colloidal nanoparticles adhere to chemically modified particle surfaces—primarily through electrostatic interactions. The nanoparticle coverage can be precisely controlled through: pH adjustment, immersion time, metal colloid concentration, nanoparticle size, surface chemistry of the polymer core. The approach is ideal for applications requiring controlled surface plasmonic properties, catalytic sites, or defined metal loading.
In-situ synthesis: Reduction of surface-bound metal ions to uniform nanoparticles (~2–3 nm)
- In this technique, metal precursor ions (AuCl₄⁻, PdCl₄²⁻, PtCl₆²⁻) are first immobilized on the particle surface via complexation or electrostatic interactions. Subsequent in-situ reduction produces nanosized metal particles directly on the polymer. This method ensures extremely uniform nanoscale metal coverage, beneficial for catalysis, sensing, and optical applications.
Electroless deposition: Formation of continuous metal nanocoatings with adjustable thickness
- Electroless metal deposition enables the formation of continuous, tunable metal films. Metal nanoparticles already immobilized on the polymer serve as catalytic seeds. In an auto-catalytic plating bath containing the metal ions and a reducing agent, a coherent metal nanoshell grows around the particle. These technique is available for gold, silver and cooper.
