Sentence:  Related to micelle formation is the technologically important ability of detergent actives to congregate at oil water interfaces in such a manner that the polar ( or ionized ) <WSD>end</WSD> of the molecule is directed towards the aqueous phase and the hydrocarbon chain towards the oily phase . 
Meaning of the word marked with <WSD> tags:  the surface at either extremity of a three-dimensional object