Laponite®-based colloidal nanocomposites prepared by RAFT-mediated surfactant-free emulsion polymerization: the role of non-ionic and anionic macroRAFT polymers in stability and morphology control

Thaíssa C Chaparro,Muriel Lansalot,Elodie Bourgeat-Lami,Rodrigo D Silva,Franck D'Agosto,Amilton Martins Dos Santos,Pierre-Yves Dugas

doi:10.1039/d0py00720j

Abstract

The synthesis of Laponite®-based nanocomposite latexes by reversible addition-fragmentation chain transfer (RAFT)-mediated surfactant-free emulsion polymerization using different macroRAFT agents is described.

Highlights

In recent years, waterborne processes have emerged as versatile techniques for the production of nanocomposites and for tailoring their properties.[1]
The incorporation of ethylene glycol units in the copolymers has a notable effect on the adsorption process when compared to pure PAA, being more favorable when poly(ethylene glycol) (PEG) is disposed as pendent segments, rather than in a linear configuration
We studied the effect of the nature of macroRAFT agents on the stability and morphology of Laponite®-containing nanocomposite latexes prepared via the RAFT-assisted encapsulating emulsion polymerization (REEP) strategy

Summary

Introduction

Even at very low levels, can provide various advantages to the resulting hybrid materials, when compared to pure polymers. The nanocomposite latex showed an armored morphology as a result of co-assembly and/or heterocoagulation events between chain extended macroRAFT agent-adsorbed clay platelets and block copolymer nano-objects formed in the water phase by PISA. Such a morphology can be advantageous for the colloidal stability of the system and for the mechanical properties of the film, as it results in honeycomb structures. It follows a previous study in which RAFT copolymers have been designed and synthesized by solution polymerization and evaluated in an adsorption study onto Laponite®.24 In the present work, emulsion copolymerization of MMA with BA was performed in the presence of Laponite® platelets modified with AA-, PEG- or PEGA- and BA-based macroRAFT copolymers to generate clay/polymer nanocomposite latex particles under semi-batch surfactant-free conditions

Materials

Methods

Characterization

Results and discussion

Conclusions