Vertically aligned carbon nanotube (CNT) arrays have been grown onto the carbon fiber fabric using a catalytic chemical vapor deposition (CCVD) method. The as-synthesized CNT arrays are about 20 mu m in height, and the nanotube has a mean inner and outer diameter of 2.6 nm, 5.5 nm, respectively. The CNT-grafted carbon fabric shows a hydrophobic property with a contact angle over 145 degrees, and the single CNT-grafted carbon fiber shows a sharp increase of dynamic contact angle in de-ionized water from original 71.70 degrees to about 103 degrees, but a little increase does in diiodomethane or E-51 epoxy resin. However, the total surface energy of carbon nanotube-grafted carbon fiber is almost as same as that of as-received carbon fiber. After CNTs growth, single fiber tensile tests indicated a slight tensile strength degradation within 10% for all different lengths of fibers, while the fiber modulus has not been significantly damaged. Compared with the as-received carbon fibers, a nearly 110% increase of interfacial shear strength (IFSS) from 65 to 135 MPa has been identified by single fiber pull-out tests for the micro-droplet composite, which is reinforced by as-received carbon fiber or CNT-grafted carbon fiber. (C) 2011 Elsevier B.V. All rights reserved.