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）就越小，也可以(yi)說是電極(ji)電勢改變(bian)了電極(ji)界面(mian)剩余電荷量，從而便會(hui)影(ying)響到「界面(mian)張力」。

 界面的同(tong)一側帶有(you)相同(tong)符號的剩余電(dian)荷(he)，由于同(tong)性電(dian)荷(he)之間的排(pai)斥作用(yong)都力圖使界面擴大，兩(liang)作用(yong)力剛好(hao)相互抵(di)銷。

任(ren)何兩界(jie)(jie)(jie)(jie)面(mian)(mian)(mian)(mian)都存在(zai)著界(jie)(jie)(jie)(jie)面(mian)(mian)(mian)(mian)張力(li)，電(dian)(dian)(dian)(dian)極(ji)／溶液界(jie)(jie)(jie)(jie)面(mian)(mian)(mian)(mian)也不例(li)外。但對于電(dian)(dian)(dian)(dian)極(ji)體系(xi)來說(shuo)，界(jie)(jie)(jie)(jie)面(mian)(mian)(mian)(mian)張力(li)不僅與界(jie)(jie)(jie)(jie)面(mian)(mian)(mian)(mian)層的物質(zhi)組成有(you)(you)關(guan)，而且與「電(dian)(dian)(dian)(dian)極(ji)電(dian)(dian)(dian)(dian)位」有(you)(you)關(guan)。電(dian)(dian)(dian)(dian)極(ji)界(jie)(jie)(jie)(jie)面(mian)(mian)(mian)(mian)的剩余(yu)電(dian)(dian)(dian)(dian)荷(he)都是同性的，同性電(dian)(dian)(dian)(dian)荷(he)有(you)(you)斥力(li)，力(li)圖使界(jie)(jie)(jie)(jie)面(mian)(mian)(mian)(mian)擴大，而界(jie)(jie)(jie)(jie)面(mian)(mian)(mian)(mian)張力(li)力(li)圖使介面(mian)(mian)(mian)(mian)縮小，這兩個作用力(li)恰好相反而相互抵銷，所(suo)以剩余(yu)電(dian)(dian)(dian)(dian)荷(he)密度(du)增(zeng)大，界(jie)(jie)(jie)(jie)面(mian)(mian)(mian)(mian)張力(li)就(jiu)下降了。因此，帶電(dian)(dian)(dian)(dian)界(jie)(jie)(jie)(jie)面(mian)(mian)(mian)(mian)的界(jie)(jie)(jie)(jie)面(mian)(mian)(mian)(mian)張力(li)比(bi)不帶電(dian)(dian)(dian)(dian)時要小，電(dian)(dian)(dian)(dian)極(ji)表面(mian)(mian)(mian)(mian)電(dian)(dian)(dian)(dian)荷(he)密度(du)越大，界(jie)(jie)(jie)(jie)面(mian)(mian)(mian)(mian)張力(li)就(jiu)越小。

電(dian)(dian)極表面剩余電(dian)(dian)荷密度的大小與電(dian)(dian)極電(dian)(dian)位密切相關(guan)，因(yin)而有(you)了電(dian)(dian)毛細曲線。

我們根(gen)據電(dian)(dian)(dian)毛細(xi)現象，可以解(jie)釋為什么(me)「電(dian)(dian)(dian)極(ji)電(dian)(dian)(dian)勢(shi)」常能影響電(dian)(dian)(dian)極(ji)表(biao)面的(de)(de)某些性(xing)質，如溶液對電(dian)(dian)(dian)極(ji)表(biao)面的(de)(de)潤濕(shi)能力、電(dian)(dian)(dian)極(ji)上氣泡的(de)(de)附著情況、電(dian)(dian)(dian)極(ji)的(de)(de)表(biao)面硬度以及溶液中電(dian)(dian)(dian)極(ji)與涂(tu)料和粘(zhan)結劑之間的(de)(de)粘(zhan)合能力等。通過調節(jie)電(dian)(dian)(dian)極(ji)電(dian)(dian)(dian)勢(shi)和采用適當(dang)的(de)(de)界(jie)面活性(xing)物質（易于在界(jie)面上吸附的(de)(de)物質），可以人為地控制這類界(jie)面性(xing)質。