Surfactants assisted processing of carbon nanotube-reinforced SiO2 matrix composites

The dispersion homogeneity of carbon nanotubes (CNTs) is one of the most critical problems in carbon nanotube matrix composites. The dispersive role to CNTs of three kinds of surfactant including cetyltrimethyl ammonium bromide (C16TMAB cationic), polyacrylic acid (PAA anionic) and C16EO (CH3(CH2)14CH2(OC2H5)10OH nonionic) was investigated. The dispersion mechanism may include steric repulsive effect and static electric effect. CNT/SiO2 (5 vol.%) composites with and without C16TMAB were fabricated by sol–gel process. The average bending strength and fracture toughness of sample prepared with C16TMAB, compared with monolithic SiO2 glass, were enhanced 88 and 146% respectively. The properties of sample fabricated without C16TMAB were enhanced only 48 and 118%.