Synthesis of magnetic polystyrene nanocomposite by emulsion polymerization using a photo-responsive emulsifier for efficient crude oil absorption

Both human health and marine life are seriously threatened by crude oil spills into bodies of water. For effective crude oil spill cleaning, we created a magnetic polystyrene (m-PS) nanocomposite. The use of magnetic nanoparticles makes crude oil absorption more environmentally friendly by making it easier to collect and recycle using an external magnetic field. To make Fe₃O₄ nanoparticles compatible with the hydrophobic styrene monomer used in emulsion polymerization, they were treated using a hydrophobic surface modification reaction. This alteration facilitated the grafting of polystyrene (PS) chains onto the nanoparticles, which then underwent emulsion polymerization. As an emulsifier, a light-responsive amphiphilic block copolymer containing coumarin was created via reversible addition-fragmentation chain transfer polymerization. This allowed for regulated emulsification and demulsification in response to UV stimulation. The synthesized m-PS nanocomposite demonstrated a crude oil absorption capacity of up to 2.31 times of its own weight, indicating its high efficiency for crude oil spill cleanup. The synthetic emulsifier exhibited a significantly lower critical micelle concentration compared to the commercial P105 emulsifier (0.0976 against 0.354 mg/mL, respectively), indicating higher efficiency and reduced environmental impact. For a more thorough comprehension of the reported results, we also assessed the Hofmeister effect in PS produced using commercial and synthetic emulsifiers.