Functionalization of cellulose nanowhiskers (CNW) was performed by means of chemical synthesisinvolving polymerization of polyaniline in emeraldine salt form (PAni SE) in the presence of CNW. Ther-mal, chemical and morphological samples properties were evaluated. Polymeric coatings were obtainedwith epoxy, aminopropyltriethoxysilane (APS), CNW and CNW/PAni SE applied on carbon steel with aconversion coating of zirconia (Zr) and the mechanical properties were evaluated. With regard to CNWfunctionalization the sample was encapsulated with PAni SE as observed by FTIR and morphologic anal-ysis, with decreased thermal stability. Regarding the mechanical properties of CNW and CNW/PAni SEpolymeric coatings, improvements in flexibility and hardness properties using the APS and Zr layer wereobserved. The adherence of polymer coatings improved by the incorporation of CNW and CNW/PAni SE.Through morphological analysis it was observed that CNW shows good dispersion in the polymer matrixwithout agglomerates formation.