Abstract: The present invention relates to a 2-part adhesive formulation comprising, in the first part, water, a surfactant, and a protected alkylborane complex, and an acrylic monomer and a trialkylborane-displacing initiator in the second part. The formulation can be applied to a low surface energy substrate to make an effective adhesive without the aid of any surface pretreatment. The adhesive formulation can also be prepared by combining the complex with a mixture of the water, the surfactant, the monomer, as well as other additives and thixotropes, and applying the combination to the low surface energy substrate.