The amphiphilic aprotic vinyl monomer, N-vinylacetamide (NVA), was firstly employed to fabricate double network (DN) hydrogels in water at 37 degrees C. Although N,N-methylenebisacrylamide as a crosslinker did not form hydrogels, novel crosslinker which is based on the structure of NVA was effective in creating first and second network hydrogels. DN structures of nonionic NVA hydrogels will expand the pool of various functional hydrogels, as well as give rise to stronger NVA hydrogel preparations.