An attempt to modify N-isopropylacrylamide hydrogels exhibiting a thermoshrinking volume phase transition of the lower critical solution temperature type in aqueous solution has been made in this work via the adjustment of crosslinking density and/or the introduction of acidic monomers within the gel structure by copolymerization with acrylic acid or methacrylic acid. The increase in crosslinking density twas resulted in the decrease in water content and the increase in phase transition temperature of the resulting NIPAAm gels. The introduction of acidic monomers within the gel network has also been found to cause the overall increase in water content and the sensitive change in the phase transition temperature. While in a lower pH region (pH<4) the decrease in water content of gels and the more favorable thermosensitive phase transition behavior were observed, at pH>5 the considerable decrease in thermosensitivity and the abrupt increase in both water content and degree of volume swelling were observed, as confirmed by the DSC measurements.