Effect of salts on size and morphology of extruded dimethyldioctadecylammonium bromide or chloride vesicle for polymeric nanocapsules synthesis via templating emulsion polymerization

W Rusli; A M van Herk

doi:10.1016/j.jcis.2020.11.116

Effect of salts on size and morphology of extruded dimethyldioctadecylammonium bromide or chloride vesicle for polymeric nanocapsules synthesis via templating emulsion polymerization

J Colloid Interface Sci. 2021 Apr:587:393-401. doi: 10.1016/j.jcis.2020.11.116. Epub 2020 Dec 25.

Authors

W Rusli¹, A M van Herk²

Affiliations

¹ Institute of Chemical and Engineering Sciences (ICES), 1 Pesek Road, Jurong Island, Singapore 627833.
² Institute of Chemical and Engineering Sciences (ICES), 1 Pesek Road, Jurong Island, Singapore 627833. Electronic address: alexander_herk@ices.a-star.edu.sg.

PMID: 33370661
DOI: 10.1016/j.jcis.2020.11.116

Abstract

In preparing polymer capsules by vesicle templated emulsion polymerization, the initial size and morphology of the biomimetic vesicle template dictate the final size and morphology of the capsules. The presence of salts (NaCl, NaBr and LiCl) influences the size, dispersity (PDI) and morphology of dimethyldioctadecylammonium bromide or chloride (DODAX, X = Br^- or Cl^-) vesicles, prepared via membrane extrusion. DODAX vesicles in pure water exhibit broad size distributions with PDI of 0.5 and 0.3 for DODAB and DODAC, respectively. Addition of salts in water before (pre-addition) and after (post-addition) extrusion reduces the size and PDI of the vesicles significantly and results in various morphology investigated with cryo-TEM. It is observed that at low salt concentration (≤0.5 mM) in pre-addition, DODAX exists as a nice quasi spherical unilamellar vesicle, suitable for vesicle templated polymerization whereas in post-addition of salt at any concentration, the morphology is dominated by structures not suitable for templating application. The information obtained here is crucial for vesicle templated emulsion polymerization and it will be shown that there is a relationship between vesicle template morphology and final polymer capsule morphology.

Keywords: Dimethyldioctadecylammonium bromide or chloride (DODAX, X = Br(−) or Cl(−)); Vesicle morphology; Vesicle templated emulsion polymerization; Vesicles; cryo-TEM.