▁called ▁VI E CA , ▁can ▁be ▁implemented ▁in ▁a ▁quite ▁simple ▁way ▁on ▁every ▁Wil hel my ▁balance . ▁ ▁Single - fi ber ▁Wil hel my ▁method ▁Dynamic ▁Wil hel my ▁method ▁applied ▁to ▁single ▁fib ers ▁to ▁measure ▁adv ancing ▁and ▁re ced ing ▁contact ▁angles . ▁ ▁Single - fi ber ▁men is cus ▁method ▁An ▁optical ▁variation ▁of ▁the ▁single - fi ber ▁Wil hel my ▁method . ▁Instead ▁of ▁meas uring ▁with ▁a ▁balance , ▁the ▁shape ▁of ▁the ▁men is cus ▁on ▁the ▁fi ber ▁is ▁directly ▁im aged ▁using ▁a ▁high ▁resolution ▁camera . ▁Autom ated ▁men is cus ▁shape ▁fitting ▁can ▁then ▁directly ▁measure ▁the ▁static , ▁adv ancing ▁or ▁re ced ing ▁contact ▁angle ▁on ▁the ▁fi ber . ▁ ▁W ash burn ' s ▁equation ▁cap ill ary ▁rise ▁method ▁ ▁In ▁case ▁of ▁a ▁por ous ▁materials ▁many ▁issues ▁have ▁been ▁raised ▁both ▁about ▁the ▁physical ▁meaning ▁of ▁the ▁calculated ▁p ore ▁diameter ▁and ▁the ▁real ▁possibility ▁to ▁use ▁this ▁equation ▁for ▁the ▁calculation ▁of ▁the ▁contact ▁angle ▁of ▁the ▁solid , ▁even ▁if ▁this ▁method ▁is ▁often ▁offered ▁by ▁much ▁software ▁as ▁cons olid ated . ▁Change ▁of ▁weight ▁as ▁a ▁function ▁of ▁time ▁is ▁measured . ▁ ▁See ▁also ▁ ▁G oni ometer ▁Men is cus ▁( liqu id ) ▁Por os imet ry ▁S ess ile ▁drop ▁technique ▁Sur face ▁t ension ▁W et ting ▁ ▁References ▁ ▁Further ▁reading ▁Pierre - G illes ▁de ▁G ennes ,