Effect of particle size on the surface properties and morphology of ground flax

► We examine the effect of grinding on the surface properties of flax fibers. ► Water sorption, copper number, OH number and surface O/C ratio increase. ► DP, crystallite size and dispersive component of surface energy decrease. ► O/C ratio and OH number vs. particle size curves have local maxima. ► Effects include destruction of waxy layer and increase of crystalline imperfections.