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 (C(16)TMAB cationic), polyacrylic acid (PAA anionic) and C16EO (CH3(CH2)(14)CH2(OC2H5)(10)OH nonionic) was investigated. The dispersion mechanism may include steric repulsive effect and static electric effect. CNT/SiO2 (5 vol.%) composites with and without C(16)TMAB were fabricated by sol-gel process. The average bending strength and fracture toughness of sample prepared with C(16)TMAB, compared with monolithic SiO2 glass, were enhanced 88 and 146% respectively. The properties of sample fabricated without C(16)TMAB were enhanced only 48 and 118%. (C) 2003 Elsevier Ltd and Techna S.r.l. All rights reserved.