A pair of chemically powered self-propelled nanodimers can exist in a variety of bound and
unbound states after undergoing a collision. In addition to independently moving unbound
dimers, bound Brownian dimer pairs, whose center-of-mass exhibits diffusive motion, self-
propelled moving dimer pairs with directed motion, and bound rotating dimer pairs, were
observed. The bound pairs arise from a solvent depletion interaction, which depends on the
nonequilibrium concentration field in the vicinity of dimers. The phase diagram reported in …