['Ali', 'reported', 'that', 'a', 'particularly', 'useful', 'surfactant', 'is', 'a', 'blend', 'of', 'polyethylene', 'glycol', 'esters', 'of', 'fatty', 'acids', 'and', 'ethoxylated', 'alkylphenols', '[', '15', ']', '.']