Self-assembly and nanostructure of poly(vinyl alcohol)-graft-poly(methyl methacrylate) amphiphilic nanoparticles

Hen Moshe Halamish; Jiří Trousil; Dmytro Rak; Kenneth D Knudsen; Ewa Pavlova; Bo Nyström; Petr Štěpánek; Alejandro Sosnik

doi:10.1016/j.jcis.2019.06.047

Self-assembly and nanostructure of poly(vinyl alcohol)-graft-poly(methyl methacrylate) amphiphilic nanoparticles

J Colloid Interface Sci. 2019 Oct 1:553:512-523. doi: 10.1016/j.jcis.2019.06.047. Epub 2019 Jun 17.

Authors

Hen Moshe Halamish¹, Jiří Trousil², Dmytro Rak³, Kenneth D Knudsen⁴, Ewa Pavlova⁵, Bo Nyström⁶, Petr Štěpánek⁵, Alejandro Sosnik⁷

Affiliations

¹ Laboratory of Pharmaceutical Nanomaterials Science, Department of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa, Israel.
² Institute of Macromolecular Chemistry, Czech Academy of Sciences, Prague, Czechia; Department of Analytical Chemistry, Charles University, Faculty of Science, Prague, Czechia.
³ Institute of Experimental Physics, Slovak Academy of Sciences, Košice, Slovakia.
⁴ Department of Physics, Institute for Energy Technology, Kjeller, Norway.
⁵ Institute of Macromolecular Chemistry, Czech Academy of Sciences, Prague, Czechia.
⁶ Department of Chemistry, University of Oslo, Oslo, Norway.
⁷ Laboratory of Pharmaceutical Nanomaterials Science, Department of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa, Israel. Electronic address: sosnik@technion.ac.il.

PMID: 31234124
DOI: 10.1016/j.jcis.2019.06.047

Abstract

Hypothesis: Poly(vinyl alcohol)-g-poly(methyl methacrylate) (PVA-g-PMMA) amphiphilic copolymers self-assemble to form multi-micellar colloidal systems.

Experiments: A PVA-g-PMMA copolymer containing 16-17% w/w of PMMA was synthesized by the free radical graft polymerization of methyl methacrylate on a PVA backbone by utilizing cerium(IV) ammonium nitrate as initiator and tetramethylethylenediamine (TEMED) as initiation activator. The aggregation behavior of the copolymer in water was comprehensively characterized by dynamic light scattering (DLS) and static light scattering (SLS), small angle neutron scattering (SANS), asymmetrical flow field-flow fractionation (A4F) and transmission electron microscopy (TEM). The colloidal stability before and after non-covalent crosslinking of PVA domains with boric acid was assessed by DLS. Finally, nanoparticles were nano spray-dried.

Findings: This copolymer self-assembles in water to form a complex nanostructure of low aggregation number particles (ca. 12-15 nm in diameter) that aggregate into larger ones with size ca. 60-80 nm, as determined by SANS and TEM. In addition, boric acid-crosslinking preserves the nanoparticle size, while conferring full physical stability under extreme dilution conditions. Nano spray-drying consolidates the crosslnking and enables the production of a dry flowing powder that upon re-dispersion in water regenerates the nanoparticles without major size changes.

Keywords: Asymmetric flow field-flow fractionation (A4F); Nano spray-drying; Poly(vinyl alcohol)-poly(methyl methacrylate) amphiphilic nanoparticles; Polymer self-assembly; Small-angle neutron scattering (SANS).