Poly(N-isopropylmethacrylamide) has significant potential for designing thermosensitive new materials. It is similar with well-known poly(N-isopropylacrylamide) hydrogels. The influence of the α-methylation on the each monomer unit in the main chain exhibits weaker intermolecular interactions between the amide group. The method of thermally-initiated free radical polymerization was applied to synthesize a series of poly(N-isopropylmethacrylamide) hydrogels with different cross-linker amount. The micrographs, obtained by the scanning electron microscopy method, indicated a semi-homogeneous crosslinked network of these hydrogels which can be classified as macroporous. The swelling behavior at room temperature of these negatively thermosensitive hydrogel exhibit a little higher swelling degree in acidic media (at pH 2.0 swelling degree was about 21) in relation to the weakly basic media (at pH 7.4 swelling degree was about 18). The poly(N-isopropylmethacrylamide) hydrogel topology showed much free space within the crosslinked polymer chains in the swollen state and they could be use as absorbers of water, diluents, dissolvent, solutions, or as carriers for active substances
