In this study, dense thin films containing carboxylic acid-functionalized carbon nanofibers (O-CNFs) are fabricated by a two-step approach involving solution filtering and mechanical compression through a rolling process. Optical images reveal a notable change from porous to dense in the surface morphology of the rolled O-CNF thin film. Moreover, test results show that the tensile strength and electrical conductivity of the rolled thin film are improved by approximately 400% in comparison to the non-rolled thin film. Upon fracture, electron microscope image shows significant pull-out and alignment of O-CNFs parallel to the direction of the applied load due to interlocking mechanism within the highly entangled O-CNF network. (C) 2013 Elsevier B.V. All rights reserved.