Carbon fibers (CFs) have a unique combination of properties which allow them to be widely
used as reinforcing materials in advanced polymer composites. The mechanical properties
of CF-reinforced polymer composites are governed mainly by the quality of interfacial adhesion
between the CFs and the polymer matrix. Surface treatments of CFs are generally
carried out to introduce chemical functional groups on the fiber surfaces, which provide
the ability to control the surface characteristics of CFs. In this study, we review recent experimental
studies concerning various surface treatment methods for CFs. In addition, direct
examples of the preparation and properties of CF-reinforced thermosetting composites are
discussed.