Hydrophilic encapsulation of multi-walled carbon nanotubes using admicellar polymerization

• Admicellar polymerization was used to encapsulate MWCNTs.
• Hydrophilic and hydrophobic polymers were encapsulated on MWCNTs.
• Two-site adsolubilization model was modified to calculate aggregation number of surfactants on MWCNTs surface.
• Modified MWCNTs remained stable in aqueous media for atleast 3 days.

Admicellar polymerization (AP), a surface analog of emulsion polymerization was used to obtain a thin layer of hydrophilic polymer coating on multi-walled carbon nanotubes (MWCNTs). The hydrophilic nature can facilitate integration of carbon nanotubes into a variety of composite materials. To develop hydrophilic polymer by AP, acrylate monomers were copolymerized using sodium dodecyl sulfate as a surfactant. Development of a system for AP involves measurement of surfactant adsorption and adsolubilization or partitioning of monomer into adsorbed structures (reverse hemimicelles). A modified two-site adsolubilization model was used to calculate the size of surfactant aggregates over the surface of MWCNTs and a binary adsolubilization model was employed to predict number of monomers adsolubilized from single component experiments. Adsolubilized monomers were polymerized to form a polymer nanocomposite, which was then hydrolyzed to obtain a hydrophilic nanocomposite. SEM, energy dispersive spectroscopy (EDS), thermo gravimetric analysis (TGA) and FT-IR confirmed the formation of polymer on multi-walled carbon nanotubes (MWCNTs). Modified MWCNTs readily dispersed in aqueous media and were stable after 3 days.

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