Fabrication and Dielectric Properties of Soft-core Helical Particles Using Spirulina Platensis as Templates

Abstract

Aiming at the lightweight filler particles with good dielectric properties in the composites, helical Spirulina platensis were chosen as templates to produce microscopic helical soft-core filler particles by an electroless deposition technique. The morphology and appearance of the coated Spirulina platensis was analysed with optical microscopy and scanning electron microscopy respectively, the result showed that the particles were successfully coated with a uniform metal coating and their initial helical shape were perfectly replicated. The dielectric properties of these helical soft-core filler particles embedded in epoxy resin were studied in detail, which showed that with the coating thickness increase, the real and imaginary part of permittivity of the composites both increase in a frequency of 2–18 GHz. These soft-core metallised helical microorganisms are lightweight and have good dielectric properties. The metal content in the composites is only 6.6 vol% when the percolation threshold occurs. Such low metal content can reach percolation point is attributed to the filler particles’ soft-core structure and long helical shape advantage. Keywords: Microorganism; bio-replicated forming; soft-core helical particle; electroless deposition; dielectric property