We have obtained keratin-based micro-tubes by heating keratin fibres at temperatures above 240 degrees C under nitrogen atmosphere. The morphology and molecular mobility for micro-tubes prepared at 245 and 300 degrees C from fibres emptied of cortical material were investigated by H-1 and C-13 NMR spectroscopy, H-1 spin-diffusion and C-13 longitudinal relaxation in the rotating frame (T-1 rho(C)). The micro-tubes have a three-phase morphology given by rigid, interfacial and amorphous fractions similar to the cuticle with the largest content of the rigid domain for the micro-tube obtained at 300 degrees C. Proton spin-diffusion experiments reveal that the rigid domain sizes are comparable in both 245 and 300 degrees C micro-tubes, but the 300 degrees C ones have larger chain disorganization. C-13 NMR investigation shows the significant presence of beta-sheet morphology in micro-tubes that is strongly enhanced by the thermal treatment. (C) 2011 Elsevier B.V. All rights reserved.