Tunable Morphology and Hydrophobicity of Polyfluoroacrylate/Clay Nanocomposite Prepared by In Situ RAFT Polymerization in Miniemulsion

Abstract

This investigation reports preparation of polyfl uoroacrylate/clay nanocomposite with armored and encapsulated morphology via in situ reversible addition-fragmentation chain transfer (RAFT) polymerization in miniemulsion. In this case, 2,2,3,3,4,4,4-heptafl uoro butyl acrylate (HFBA) is polymerized in miniemulsion in the presence of sodium montmorillonite (NaMMT) using 2-cyanopropyl dodecyl trithiocarbonate (CPDTC) as a RAFT agent. Gel permeation chromatography (GPC) analysis shows that the polymers have controlled molecular weights as well as narrow dispersity ( Ð ≈ 1.1). The morphology of nanoclay can be tuned by varying the interaction with different functional comonomers. Nanoclay is encapsulated and intercalated in presence of poly (ethylene glycol) methyl ether methacrylate (PEGMEMA) as comonomer. Addition of 2-acryloxy ethyl trimethyl ammonium chloride (AETAC) as functional comonomer leads to exfoliation of nanoclay resulting armored morphology, as evidenced by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM) analyses. Poly(2,2,3,3,4,4,4-heptafl uoro butyl acrylate) (PHFBA) armored with nanoclay shows improved thermal stability and water resistance.

Polymer Encapsulation of Single Clay Platelets by Emulsion Polymerization Approaches, Thermodynamic, and Kinetic Factors

“…As in polymer–polymer core shell particle formation, the interplay of thermodynamic and kinetic factors is also operating in clay encapsulation through (mini)emulsion polymerization. Looking from the starting point of miniemulsion polymerization, thermodynamically the clay has to be modified hydrophobically to make it miscible with the monomer initially . But the interfacial tensions change during the polymerization and the resulting morphology can still be armored latex particles.…”

“…But the interfacial tensions change during the polymerization and the resulting morphology can still be armored latex particles. An interesting example is given by Chakrabary and Singha where the use of neutral functional monomer, in combination with a fluorinated acrylate in miniemulsion polymerization, led to encapsulated Cloisite hybrid latex particles (multiple clay platelets per particle) whereas the use of a positively charged functional monomer led to armored morphology. In emulsion polymerization, one would like to create an affinity of the monomer for the clay particle surface, this is typically done by creating a hemimicelle around the clay, using surfactant absorption on a more or less hydrophobized clay surface .…”

Designing superhydrophobic surface based on fluoropolymer–silica nanocomposite via RAFT‐mediated polymerization‐induced self‐assembly

“…In this context, RAFT offers the scope to prepare well‐defined polymer architectures in water. RAFT polymerization was successfully utilized by our group in preparing copolymers of fluoroacrylates and their nanocomposites in emulsion to construct hydrophobic polymer surface (WCA ∼120°) . Recently, Zhao et al fabricated a SHS based on poly(vinylbenzyl chloride‐ co ‐divinylbenzene), a hypercrosslinked porous polymer grown on RAFT‐functionalized graphene oxide nanosheets via emulsion polymerization .…”

Nanoclay stabilized Pickering miniemulsion of fluorinated copolymer with improved hydrophobicity via RAFT polymerization

“…In this regard, nanoclays were widely used because of their availability, ease of modication, thermal and mechanical stability, precise dimension (length $ 25-150 nm, thickness $ 1 nm) etc. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] Nanoclays are layered silicates which can be easily modied, intercalated or even exfoliated via ion exchange process in water. Pristine nanoclay has the compatibility with water, whereas modied nanoclay has the compatibility with organic substances.…”