New catanionic surfactants, phase stability and synthesis of ultrafine CdS nanoparticles.

A systematic study on the water-intake capacity of the microemulsion formed using a catanionic surfactant (synthesized by taking equimolar mixture of acid and amine) with varying hydrocarbon chain length of the acid has been carried out. A decrease in the water-intake capacity with increase in the chain length was observed. Shorter chain length of co-surfactant (1-butanol compared to 1-octanol) led to higher water-intake capacity of microemulsions which may also be attributed to the high hydrophilic-lipophilic balance (HLB) of 1-butanol. Three new microemulsions based on catanionic surfactants have been used to synthesize quantum dots of CdS. The size of CdS quantum dots decreased with increase in chain length of the acid component of the catanionic surfactant.