Nonionic surfactants are omnipresent in our everyday life and used in modern drug delivery. The synthesis of degradable surfactants is crucial to simplify the purification of final products or reduce polymer waste. Here, we present the synthesis of a new amphiphilic 2-n-dodecyl-2-oxo-1,3,2-dioxaphospholane, a monomer for the anionic ring-opening polymerization towards poly(ethylene alkyl phosphonate)s. The novel monomer is copolymerized with 2-ethyl-2-oxo-1,3,2-dioxaphospholane to produce well-defined, water-soluble, and surface-active copolymers with molar masses up to 18,400 g mol−1, dispersities between 1.2 and 1.3, and critical aggregation concentrations below 0.07 g L−1. The reactivity ratios of the two comonomers indicate a random monomer incorporation with r1 = 1.46 and r2 = 0.68. Adjusting the comonomer ratio changes the amphiphilicity of the resulting copolymers. They are applied in the free radical miniemulsion polymerization to produce well-defined nanoparticles. The intrinsic hydrolytic degradability of polyphosphonates makes these polymers interesting candidates for use in, emulsion stabilization for drug delivery or cosmetics.