Simultaneous Effects of Ionic Surfactant and Salt on Drop-Interface Coalescence

In this research. the effect of mixed salts together with mixed ionic surfactants on dropinter/a ce coalesce nce time was studied for the system of water (d) / toluenetc) as amodel sys tem. sodium dodecy l sulfate (sds) and cety l trimethyl ammonium bromide(ctab) as anionic and cationic surfac tants were used. sodium chloride (nacl) andmagn esium sulfate were used us salts. in the f irst stage of experiments. the sy stem ofwater and toluene was influenced separately with sds+nac i. sds+mgs04•ctab+nacl and ctab+mgs0 4• it was observed that drop size increased withsds+nacl and also with sds+mgs0 4. part ial coalescence times increased f or allsystems. overall. this increase a/ coa lescence time was more obvious when ctab wasapplied. also reduction in drop size was observed. in the case a/ mixed surfa ctants withsingle salt. it was observed that partial coalesce nce was suppressed (or the sys tem with(sds+ctab)+mgs0 4. 011 the other hand. drop size decreased and total coalescencetime increased. this may be due to the difference between the anions and cations ofthetwo salts. for the case ofmixed surf actants with mixed salts, drop size and coalescencetime decreas ed.