Interaction of Cationic, Anionic, and Nonionic Macroraft Homo- and Copolymers with Laponite Clay

Author(s)

Chaparro, Thaissa de Camargo ^{[1, 2]} ; Silva, Rodrigo Duarte ^[1] ; Monteiro, Igor Stefanichen ^[1] ; Barros-Timmons, A. ^[3] ; Giudici, Reinaldo ^[4] ; dos Santos, Amilton Martins ^[1] ; Bourgeat-Lami, Elodie ^[2]

Affiliation

^[1] Univ Sao Paulo, Engn Sch Lorena, BR-12602810 Lorena, SP - Brazil

^[2] Univ Lyon, Univ Claude Bernard Lyon 1, CPE Lyon, CNRS, UMR 5265, C2P2, 43, Bvd 11 Novembre 1918, F-69616 Villeurbanne - France

^[3] Univ Aveiro, Dept Chem, CICECO, Campus Univ Santiago, P-3810193 Aveiro - Portugal

^[4] Univ Sao Paulo, Polytech Sch, Dept Chem Engn, BR-05508010 Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: Langmuir; v. 35, n. 35, p. 11512-11523, SEP 3 2019.
• Web of Science Citations: 0

Abstract

The functionalization of Laponite RD platelets with different cationic, anionic, and nonionic homo- and copolymers synthesized by reversible addition-fragmentation chain transfer (RAFT) has been investigated. The effective interaction of the macromolecular RAFT agents (macro-RAFTs) with the inorganic particles is known to be of crucial importance for the successful coating of minerals with polymers via RAFT-mediated emulsion polymerization to produce polymer-encapsulated inorganic particles. The macroRAFT agents synthesized in the present work contain carefully selected reinitiating R groups, which bear either ionizable tertiary amine or quaternary ammonium moieties (from 2-(dimethylamino)ethyl methacrylate, DMAEMA), negatively charged acrylic acid (AA) repeat units, or neutral polyethylene glycol (PEG) side chains, and are capable of interacting with Laponite via different adsorption mechanisms. The equilibrium adsorption of these RAFT (co)polymers was investigated by the plotting of adsorption isotherms, and either L-type or H-type curves were obtained. The hydrophobicity of the macroRAFT was shown to promote adsorption, as did the pending configuration of the PEG block. Charge repulsion between AA and the negatively charged surface of Laponite at pH 7.5, on the other hand, was prejudicial for adsorption, while the strong electrostatic interaction between the cationic DMAEMA molecules and the Laponite surface led to high-affinity-type curves. (AU)

• FAPESP's process: 10/19919-6 - Synthesis of nanocomposites with anisotropic properties by controlled radical emulsion polymerization
• Grantee: Thaíssa de Camargo Chaparro
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)