A Roadmap towards Successful Nanocapsule Synthesis via Vesicle Templated RAFT-Based Emulsion Polymerization

Abstract

Vesicle templated emulsion polymerization is a special form of emulsion polymerization where the polymer is grown from the outside of the vesicle, leading to nanocapsules. Cost effective nanocapsules synthesis is in high demand due to phasing out of older methods for capsule synthesis. Although the first indications of this route being successful were published some 10 years ago, until now a thorough understanding of the parameters controlling the morphologies resulting from the template emulsion polymerization was lacking. Most often a mixture of different morphologies was obtained, ranging from solid particles to pro-trusion structures to nanocapsules. A high yield of nanocapsules was not achieved until now. In this paper, the influence of initial vesicle dispersion, choice of the Reversible Addition-Fragmentation chain Transfer (RAFT) species and oligomer, monomer and crosslinker have been investigated. It turns out that good initial vesicle dispersion, molecular control of the RAFT process, a not too hydrophobic monomer and some crosslinking is needed to result in high yield of nanocapsules. In previous work, the level of RAFT control was often suboptimal and not properly verified and although nanocapsules were shown, other morphologies were also present. We now believe we have a full understanding of vesicle templated nanocapsules synthesis, relevant to many applications.

Experimental Investigation of Stability of Silica Nanoparticles at Reservoir Conditions for Enhanced Oil-Recovery Applications

“…Cryo-TEM measurements were performed on an FEI Titan Krios equipped with automated sample loader and a field-emission gun (FEG) operating at 300 kV. Images were recorded with Falcon II camera (4 × 4) with magnification of 29,000 and pixel size of 2.873 Å [ 30 ]. For SEM imaging, diluted nanofluid was placed on a coverslip.…”

“…The size of nanoparticles such in suspension was measured using ZetaSizer Nano dynamic light scattering (DLS) (Malvern Panalytical, Malvern, UK) in a standard 12 mm polystyrene cuvette. The samples was measured at 25 °C without any dilution at 173º backscatter [ 30 ]. The measured particle size for FNP, FNP-MD and ANP are 142.5 nm, 168.3 nm and 21.4 nm, respectively.…”

Effect of Template Type on theTrametes versicolorLaccase-Catalyzed Oligomerization of the Aniline Dimerp-Aminodiphenylamine (PADPA)

“…By the term “template”, we mean an additive that has a desired influence on the outcome of a chemical or enzymatic reaction in terms of chemical structure so that the structure is “dictated” by the template molecules. 15,41−53 For the particular case investigated, the desired reaction products should resemble PANI-ES (Scheme 1). 19,54 The templates chosen for the comparison with AOT vesicles were vesicles formed from a 1:1 molar mixture of sodium dodecylbenzenesulfonate (SDBS) and decanoic acid (DA), SDBS micelles, and the sodium salt of the polyelectrolyte sulfonated polystyrene (often abbreviated as SPS).…”

Review on Synthesis of Colloidal Hollow Particles and Their Applications

“…11,12 The other technique, nonsacrificial templating, also omits this step because polymerization occurs in the bilayer of the surfactant-based hollow vesicle. 13,14 However, the control of void size and shell thickness of HL particles is still a great challenge. In addition, nonspherical HL particles with anisotropic properties are particularly attractive, although the deviation from spherical shape is rather atypical and requires a multistep procedure.…”

“…The self-templating method is, therefore, introduced. Based on this technique, the void inside the polymer particle can be generated by either the osmotic swelling process during the neutralization step or the phase separation during the seeded emulsion polymerization (SEP). ,, Thermodynamically, the osmotic swelling method is limited to spherical structure and requires the hydrophilic core-hydrophobic shell particle, , whereas the SEP generates polymeric HL particle in one-pot through the migration of seed polymer toward the shell region without core removal. , The other technique, nonsacrificial templating, also omits this step because polymerization occurs in the bilayer of the surfactant-based hollow vesicle. , However, the control of void size and shell thickness of HL particles is still a great challenge. In addition, nonspherical HL particles with anisotropic properties are particularly attractive, although the deviation from spherical shape is rather atypical and requires a multistep procedure. , …”