Dextran-Coated Latex Nanoparticles via Photo-RAFT Mediated Polymerization Induced Self-Assembly.

Area of Science:

• Polymer Chemistry
• Materials Science
• Nanotechnology

Background:

• Traditional latex formulations often rely on small, toxic molecular surfactants.
• There is a growing need for environmentally friendly alternatives in materials science.
• Polysaccharide-based nanoparticles offer a biodegradable and non-toxic approach.

Purpose of the Study:

• To develop a free-surfactant, core/shell nanoparticle latex using polysaccharide-based diblock amphiphilic copolymers.
• To investigate an in situ formulation strategy for these nanoparticles in an aqueous environment.
• To explore the impact of copolymer composition on nanoparticle size and morphology.

Main Methods:

• Synthesis of a hydrophilic dextran-based macromolecular chain transfer agent (eDexCTA) with a photosensitive thiocarbonylthio group.
• Photo-initiated reversible addition fragmentation chain transfer (RAFT) polymerization for in situ self-assembly.
• Chain extension of eDexCTA with 2-hydroxypropyl methacrylate (HPMA) under UV irradiation to form dextran-b-poly(2-hydroxypropyl methacrylate) (DH_X) copolymers.
• Characterization of nanoparticle size and morphology using light scattering and transmission electron microscopy.

Main Results:

• Successful in situ formulation of amphiphilic diblock copolymers (DH_X) in water.
• Formation of exclusively spherical core/shell nanoparticles (SCDH_X) with sizes ranging from 20 nm to 240 nm.
• Nanoparticle size was found to increase with the length of the poly(2-hydroxypropyl methacrylate) (PHPMA) block.

Conclusions:

• Dextran-based diblock copolymers synthesized via photo-RAFT polymerization enable the in situ formation of environmentally friendly, surfactant-free nanoparticles.
• This method provides a tunable approach to control nanoparticle size for potential applications in green latex formulations.
• The developed nanoparticles represent a promising sustainable alternative to conventional surfactant-stabilized latex systems.