synthesized were poly(N-isopropylacrylamide) (PNIPAM) latex particles having an average particle size of about 200 nm. 150ml_ of D.l. water was heated to 90°Cin the 1L- jacketed reactor at the stirring speed of 200rpm. 1.5g of ammonium persulfate and 1.5g of sodium hydrogen carbonate was added. 30g of N-lsopropylacrylamide (NIPAM) and 0.3g of N,N -methylenebis (acrylamide) (BIS) dissolved in 750ml_ of water was added into the reactor at the feed rate of 25mL/min for 30min. The mixture was stirred for another 30min after the second feed of 0.3g NIPAM, 0.03g BIS and 0.3g acrylic acid (AA) dissolved in 7.5ml_ water was fed into the reactor at the rate of 1 5mL/min. The total 900ml_ mixture was allowed to stir at 90°Cfor another 3hr. The final latex was then filtered to remove aggregates and stored in glass bottle in 60°Coven. Latex particles were prepared in a few different batches to evaluate their stability against aggregation as well as their thermal response (i.e. response to temperature). The latex particles were characterized by scanning electron microscopy (SEM) and by performing dynamic light scattering (DLS) experiments. Scanning electron microscopy (SEM) of latex particles FIG. 4A and FIG. 4B are SEM images of PNIPAM latex particles taken at different degree of magnifications (i.e. 5,000x and 20,000x respectively). The latex particles were prepared via emulsion polymerization with 1% acrylic acid (AA) and 1% , -methylenebis (acrylamide) (BIS) crosslinker by weight of the monomer latex particles in the absence of a SDS surfactant, and dried at an elevated temperature. As shown in FIG. 4A and FIG. 4B, the PNIPAM latex particles were stable against aggregation. The acrylic acid on the surface of the latex particles provided sufficient charge for latex particles to stabilize in aqueous system and prevented aggregation. Therefore, as demonstrated, a surfactant