電極電勢的變化會影響界面張力的大小，這種現象稱為「電毛細現象，electrocapillary effect」。電極界面剩余電荷量越大，同性電荷的相互排斥越強，從而界面張力（界面自由能）就(jiu)越小(xiao)，也可以說是電(dian)(dian)極(ji)(ji)電(dian)(dian)勢(shi)改變了電(dian)(dian)極(ji)(ji)界(jie)面剩余電(dian)(dian)荷量，從而便會影響到「界(jie)面張力」。

界(jie)面(mian)的同一側帶(dai)有相同符號的剩余電荷，由于(yu)同性電荷之間的排斥(chi)作(zuo)用都力圖使界(jie)面(mian)擴大，兩作(zuo)用力剛好(hao)相互抵銷。

任何兩(liang)界(jie)面(mian)(mian)(mian)都存在著界(jie)面(mian)(mian)(mian)張(zhang)(zhang)力(li)(li)(li)(li)，電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)／溶液界(jie)面(mian)(mian)(mian)也不(bu)例外。但(dan)對(dui)于電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)體(ti)系來說，界(jie)面(mian)(mian)(mian)張(zhang)(zhang)力(li)(li)(li)(li)不(bu)僅(jin)與界(jie)面(mian)(mian)(mian)層的(de)物質組成有(you)(you)關(guan)，而(er)且與「電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)電(dian)(dian)(dian)(dian)位(wei)」有(you)(you)關(guan)。電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)界(jie)面(mian)(mian)(mian)的(de)剩(sheng)余電(dian)(dian)(dian)(dian)荷(he)都是同性的(de)，同性電(dian)(dian)(dian)(dian)荷(he)有(you)(you)斥力(li)(li)(li)(li)，力(li)(li)(li)(li)圖使界(jie)面(mian)(mian)(mian)擴(kuo)大，而(er)界(jie)面(mian)(mian)(mian)張(zhang)(zhang)力(li)(li)(li)(li)力(li)(li)(li)(li)圖使介面(mian)(mian)(mian)縮(suo)小，這兩(liang)個作用力(li)(li)(li)(li)恰好相反而(er)相互抵(di)銷，所以剩(sheng)余電(dian)(dian)(dian)(dian)荷(he)密度增(zeng)大，界(jie)面(mian)(mian)(mian)張(zhang)(zhang)力(li)(li)(li)(li)就下降了(le)。因(yin)此，帶電(dian)(dian)(dian)(dian)界(jie)面(mian)(mian)(mian)的(de)界(jie)面(mian)(mian)(mian)張(zhang)(zhang)力(li)(li)(li)(li)比(bi)不(bu)帶電(dian)(dian)(dian)(dian)時要小，電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)表面(mian)(mian)(mian)電(dian)(dian)(dian)(dian)荷(he)密度越大，界(jie)面(mian)(mian)(mian)張(zhang)(zhang)力(li)(li)(li)(li)就越小。

電極(ji)表面剩余電荷密(mi)度的大小與電極(ji)電位(wei)密(mi)切相關，因(yin)而有了電毛細曲(qu)線。

我們(men)根據電(dian)(dian)(dian)毛細現(xian)象，可(ke)以(yi)解(jie)釋(shi)為什么「電(dian)(dian)(dian)極電(dian)(dian)(dian)勢(shi)」常能影響電(dian)(dian)(dian)極表(biao)(biao)面的(de)某(mou)些性(xing)(xing)質(zhi)，如溶液對電(dian)(dian)(dian)極表(biao)(biao)面的(de)潤濕能力、電(dian)(dian)(dian)極上氣泡(pao)的(de)附著情況、電(dian)(dian)(dian)極的(de)表(biao)(biao)面硬度以(yi)及(ji)溶液中電(dian)(dian)(dian)極與涂料(liao)和粘結劑之(zhi)間的(de)粘合能力等(deng)。通過調節電(dian)(dian)(dian)極電(dian)(dian)(dian)勢(shi)和采用適(shi)當的(de)界面活性(xing)(xing)物質(zhi)（易(yi)于(yu)在界面上吸附的(de)物質(zhi)），可(ke)以(yi)人(ren)為地控制這類界面性(xing)(xing)質(zhi)。