A Facile Route toward Structured Hybrid Particles Based on Liquid–Solid Assembly

Abstract

Structured hybrid particles with strongly improved colloidal stability are synthesized through a facile fabrication method based on the assembly of miniemulsion droplets containing liquid monomeric precursors onto solid nanoparticles. Classical heterocoagulation experiments between solid particles with similar compositions are performed for comparison and result in coagulated samples. A two-step mechanism is proposed which involves polymerization to fixate the final hybrid particle morphology after electrostatically driven self-assembly. Negatively charged polyacrylonitrile (PAN) nanoparticles with a high degree of semicrystallinity are utilized as solid core and combined with positively charged monomer droplets of varying compositions. A simple adjustment of miniemulsion composition enables the tailored synthesis of raspberry or core–shell structured hybrid particles. While the ζ-potential strongly affects the colloidal stability, adjusting the T g of the polymer and/or the cross-linking degree after polymerization is an efficient tool to determine the final latex morphology. As-prepared hybrid dispersions can form transparent films with embedded PAN domains with an undisturbed high degree of semicrystallinity and thus show potentials in a wide variety of applications, e.g., for coatings and adhesives with reinforced mechanical properties and improved barrier performance.

Design of Raspberry‐Shaped Microcarriers with Adjustable Protrusions and Functional Groups for the Improvement of Lipase Immobilization and Biocatalysis: Environmentally Friendly Esterification of Oleic Acid for Biodiesel

“…Enzymes, especially immobilized enzymes, are highly efficient biocatalysts with high activities and specificities that have attracted the attention of many scientists . However, some key problems have hindered the development of immobilized enzymes, although they has been studied for almost a century and are used widely in medicine, food processing, biomass energy, and other fields . For example, the efficiency of immobilized lipase is restricted if the lipase is immobilized directly on a carrier, which can be attributed to the steric hindrance of lipase molecules and the microenvironment of their surfaces…”