Pickering Emulsifiers Based on Block Copolymer Nanoparticles Prepared by Polymerization-Induced Self-Assembly

Abstract

Block copolymer nanoparticles prepared via polymerization-induced self-assembly (PISA) represent an emerging class of organic Pickering emulsifiers. Such nanoparticles are readily prepared by chain-extending a soluble homopolymer precursor using a carefully selected second monomer that forms an insoluble block in the chosen solvent. As the second block grows, it undergoes phase separation that drives in situ self-assembly to form sterically stabilized nanoparticles. Conducting such PISA syntheses in aqueous solution leads to hydrophilic nanoparticles that enable the formation of oil-in-water emulsions. Alternatively, hydrophobic nanoparticles can be prepared in non-polar media (e.g., n -alkanes), which enables water-in-oil emulsions to be produced. In this review, the specific advantages of using PISA to prepare such bespoke Pickering emulsifiers are highlighted, which include fine control over particle size, copolymer morphology, and surface wettability. This has enabled various fundamental scientific questions regarding Pickering emulsions to be addressed. Moreover, block copolymer nanoparticles can be used to prepare Pickering emulsions over various length scales, with mean droplet diameters ranging from millimeters to less than 200 nm.

RAFT-mediated polymerization-induced self-assembly (RAFT-PISA): current status and future directions

“… 306 For more details on Pickering emulsifier application of PISA-prepared nanoparticles, the reader is referred to a recent review for good insight. 309 …”

Enhanced Sunscreen Effects via Layer-By-Layer Self-Assembly of Chitosan/Sodium Alginate/Calcium Chloride/EHA

“…However, good dispersibility and sustained sunscreen-release property have been two main challenges for the design of efficient nanocapsules. It has been reported that most of the sunscreen nanocapsules had poor dispersibility in emulsion [ 10 ], limiting their application in sunscreen products. The way of layer-by-layer self-assembly (LBL) was a new strategy to prepare the nanocapsules with nano-size and good dispersibility [ 11 ].…”

Stimuli‐Responsive Pickering Emulsions Regulated via Polymerization‐Induced Self‐Assembly Nanoparticles

“…The effect of the hydrophilicity of the PISA‐synthesized polymeric particles on emulsion was discovered by Armes and coworkers. [ 97 ] Changing the hydrophilicity or hydrophobicity would lead to an increase in the solubility of particles in the aqueous or oil phase, so the particles tend to dissolve in one phase, leading to demulsification. As discussed in Section 2, the pH‐responsive and CO 2 ‐responsive emulsions are mainly achieved by increasing their hydrophilicity under the addition of acid or CO 2 gas.…”