A new series of copolymer poly(N-hexadecylmeth acrylamide-co-bis(anthracen-9-ylmethyl) 2-allylmalonate) [poly(HDMA-co-DAnMAMA)]s containing swallow-tailed double anthracenyl groups and long alkyl group are designed and synthesized. The main route of the photochemical reaction of the p(HDMA-DAnMAMA)copolymer LangmuirBlodgett (LB) films is dimerization reaction between the anthracenyl groups under the irradiation of both 365 and 248 nm for limiting irradiation time, resulting to a fine negative-tone pattern. On the other hand, the anthracenyl groups act just as photodecomposition group under 248 nm for longer irradiation time, resulting to a fine positive-tone pattern. Consequently, positive-tone and negative-tone pattern are obtained by choosing not only a suitable irradiation light wavelength, but the irradiation time at 248 nm. Moreover, it is found that the exposed and unexposed regions of copolymer LB films irradiated at 248 nm have solubility differentiation in gold etchant (I2/NH4I/C2H5OH/H2O), that is to say, the gold photopatterns with the maximal resolution of the used mask can be obtained easily without any development process. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 50: 139147, 2012