New bladed habit of hexadecanoic-acid crystals observed by SEM combined with XRD, FT-IR and Raman studies

Abstract This study reports a new habit for the hexadecanoic-acid crystal, which was obtained using slow evaporation method from mixture of L-lysine hydrochloride and hexadecanoic acid in ethanol solution. All the morphological, structural, vibrational and thermal characteristics were investigated through scanning electron microscopy (SEM), X-ray diffraction, Fourier-transform infrared (FT-IR) and Raman spectroscopy, and differential scanning calorimetry techniques. The crystals were grown with transparent thin blade-like shapes, as indicated by the SEM images. From the spectroscopic analyses, we observed that hexadecanoic-acid molecules within the unit cell have adopted all-trans conformations between dimer groups formed through the hydrogen bonds, thus indicating that during the growth process the crystal has acquired a new habit which is different from those previously reported by literature.