Abstract: This document relates to materials and methods involved in providing a substrate (e.g., tooth, tooth component, inorganic dental material, skin, hair, nails, hair, lips, and eyelashes) with a desired benefit (e.g., appearance, flavor, breath freshening, and/or medicament). For example, materials and methods for contacting a tooth, tooth component, or inorganic dental material with a polyelectrolyte adhesive containing a conjugate of a polyamine (e.g., a naturally-derived polyamine and/or a synthetic polyamine), a polyphosphate, and one or more whitening agents to provide the substrate with a change in appearance (e.g., a whiter appearance, a more natural appearance, and/or a glossy appearance) are provided.