The　effect　of　an　electric　field　on　the　evaporation/boiling　heat-transfer　characteristic　of　an　evaporation　surface　with　rectangular　microgrooves　was　experimentally　investigated.　R141b　was　used　as　the　working　fluid.　The　operating　pressure　was　1.01　x　10(5)　Pa.　Experimental　results　showed　that　electric　field　significantly　affected　the　thermal　performance　of　the　evaporation/boiling　surface.　The　heat-transfer　enhancement　effects　increased　with　increased　electric　field　strength.　The　heat-transfer　coefficient　enhancement　factor　could　reach　as　high　as　1.45　under　the　applied　electric　field.　A　visualization　experimental　study　on　the　bubble　behavior　and　nucleate　site　density　was　also　conducted.　Visualization　experiment　results　indicated　that　the　bubble　departure　time　and　nucleate　site　density　decreased　with　increased　electric　field　strength.　(C)　2014　Elsevier　Ltd.　All　rights　reserved.