Tetrafunctional Block Copolymer Surfactant, Terminal Primary Hydroxyl Groups. Applications Tetronic® 701 is a tetrafunctional block copolymer surfactant terminating in the primary groups. A nonionic surfactant that is 100% active and relatively nontoxic. It provides great emulsification, wetting and defoaming properties. Tetronic® 701 is used for the following formulation types: emulsifier concentrates, microemulsions, suspension concentrates, suspo-emulsions, soluble liquids, wettable powders, oil dispersions.