Synthesis and Surface Activity of Amphiphilic 2-Acylamido-2-Methylpropane Sulfonic Acid - co-N-Isopropyl Acylamide Nanoparticles in Aqueous Media

This work is the first report to discuss the effect of nanogels solid particles to lower the surface and interfacial tension of water/air and water/styrene interface. Moreover, this work aims to use nanogels as stabilizer for miniemulsion aqueous polymerization. The present work synthesized a series of amphiphilic crosslinked N -isopropylacrylamide (NIPAAm) and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) copolymer nanogel based on aqueous copolymerization batch method. In this respect, divinylbenzene (DVB) and N,N-methylene bisacrylamide (MBA) were used as crosslinker. The chemical structure of the prepared nanogels was determined by FTIR analyses. The morphologies of the prepared nanogels were detected by TEM and SEM technique. The lower critical transition temperatures (LCST) were determined from DSC technique. The surface tension of colloidal NIPAm/AMPS dispersions was measured as functions of surface age, temperature, and the morphology of the NIPAm/AMPS nanogels. The NIPAm/AMPS nanogels reduced the surface tension of water to about 30.1 mN/m at 25 °C and a little increase at 40 °C. Surface activities of these nanogels in aqueous water were determined by surface tension measurement. The relationship between surface activity and nanogels morphologies and mol percentages of NIPAm was discussed. The surface adsorption state and surface adsorbed layer of NIPAm/AMPS dispersions were also discussed. Surface parameters such as surface excess concentration ( Γ max ), the area per molecule at interface ( A min ) and the effectiveness of surface tension reduction were determined from the adsorption isotherms of the prepared surfactants.