[en] Full text: The research aim is to analyze the structure and morphology of the β phase of the polyfluorene (PFO) obtained from reprecipitation method [1] using X-ray diffraction (XRD), Le Bail fit [2], Fourier-transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and UV-vis absorption spectroscopy. The XRD pattern presented typical PFOβ phase peaks at 2θ = 7,0°; 10,5°; 12,7°; 16,4°; 18,3°; 20,0° and 21,2° in agreement with the literature [3]. The cell dimensions were obtained from the Le Bail method (a = 13, b = 21, c = 33, α = 90, β = 90 and γ = 90) and the crystallites were oblate shapes with average size around 43.86Å. FTIR analysis allowed to identify characteristic absorption bands of PFO. By scanning electron microscopy (SEM) it was observed nanometric particles of varying sizes with morphologies similar to nanospheres. The UV-vis and photoluminescence demonstrated similar optical properties with PFO β phase, in which typical absorption and emission bands lies, respectively, at 395; 439nm and 444; 466; 497nm. Thus, the reprecipitation method was successful in obtaining polyfluorene in its crystalline phase β. References: [1] Pecher, J.; Mecking, S.; Chemical Reviews, v. 110, p. 6260–6279, 2010. [2] Pecharsky, V.; Zavalij, P. Y.; Springer US, v. 2, p. 348-405, 2005. [3] Liu, C.; Wang, C.; Macromolecules, v. 46, p. 3025–3030, 2013.