As a single cationic emulsifier

octadecyl bis-polyoxyethylene benzyl ammonium chloride (OEBA) was applied to prepare the stable octamethylcyclotetrasiloxane (D4) monomer miniemulsion without any co-stabilizers and non-ionic emulsifiers.The monomer droplet size was about 200 nm after being dispersed through a high pressure homogenizer at 30 MPa for 3 times

the size was similar to that of adding extra hexadecanol (HD).The miniemulsion including single emulsifier OEBA (0.0228 mol/L) and the others with extra-adding HD (0.0456 mol/L) were studied as comparative groups.The interfacial shear viscosity () of D4 droplets with different [OEBA] and [HD] was characterized

which was a key parameter of the oil-water interfacial film strength

affecting the stability of monomer miniemulsion.It was discovered that the stability mechanism of monomer miniemulsion with single emulsifier was different from that of conventional miniemulsion.Then D4 miniemulsion was initiated for ring-opening polymerization (ROP) by KOH solution.During the polymerization processes

change of particle size was traced through the dynamic light scattering (DLS).As the polymerization going on

whether using single emulsifier OEBA (0.0228 mol/L) or extra-adding HD (0.0456 mol/L)

the droplet size similarly reduced from 200 nm to 100 nm.Furthermore

the abilities of anti-acid

anti-alkali and anti-electrolyte of polydimethylsiloxane (PDMS) miniemulsion were defined by E0/E24.It was discovered that stability properties of the miniemulsion with single emulsifier were more excellent than those of the others.Finally

compared with the comparative group including HD

monomer conversion and corresponding polymerization rate at different polymerization stages were determined by gravimetrical method.As expected

the change of polymerization rate with single OEBA was extremely corresponded to the conventional miniemulsion polymerization mechanism.For example

there was no constant rate period in the whole polymerization process.In conclusion

D4 and PDMS miniemulsions could be successfully prepared with only a single emulsifier OEBA.