The primary objective of the study is to investigate the impact of chemicalstructure at the interface on the interface strength of fiber/matrixcomposite. A solvent based method was used to deposit trichlorosilane onE-glass fiber surfaces followed by in situ modification of the depositedlayer to prepare pure and mixed amine undecyl self assembled monolayer(SAM). The extent of fiber/matrix adhesion was determined by performingsingle fiber fragmentation test (SFFT). The SFFT data indicate that ≈ 85 %of fiber breaks obtained for epoxy composite occurs at a much lower massfraction of amine coverage for SAM while a similar number of fiber breaksoccur at a much higher mass fraction of amine coverage for aqueous solutiondeposited coupling agent system.