Structural studies for a homologous series of poly(1H,1H-fluoroalkyl alpha-fluoroacrylate)s [-{CH2CFC(O)OCH2(CF2)(n)Y}p-, Y = H or F, Nc = 1 + n = 2-12] have been performed with X-ray diffraction, differential scanning calorimetric, and polarized IR spectral measurements. At room temperature, all the homologues used have an ordered structure (crystallites) which consists of the ordering of main and fluoroalkyl side chains. The structure of crystallites depended on both length (N-c) of fluoroalkyl side chains and chemical structure. In the shorter fluoroalkyl homologues (Nc < 7), the side chains are arranged in a double-layer packing at room temperature, while they are mostly in a singlelayer packing in the longer fluoroalkyl homologues. As temperature increased, in the short fluoroalkyl homologues, the double-layer packing was more arranged around a temperature above T-g and then gradually disturbed, while in the long nuoroalkyl homologues, the single layer packing transformed into a double-layer packing above T-g. The layered structure and its change with temperature chains.