Polymers often adsorb onto colloidal substrates and significantly change the surface properties. More importantly, such adsorption can provide steric stability or induce aggregation due to polymer bridging. The electrophoretic mobility of a colloidal particle is very sensitive to the hydrodynamic layer thickness of an adsorbed neutral polymer (Hill and Saville, Colloids and Surfaces A: Physicochem. Eng. Aspects, 2005). Therefore, to better understand the complex dynamics of polymer adsorption and surface reconformation, we built a novel apparatus, involving optical tweezers, that probes the kinetics and thermodynamics of polymer adsorption onto a single colloidal sphere by measuring the electrophoretic mobility. This approach avoids the deleterious effects of sedimentation and flocculation, and it provides the evolving hydrodynamic layer thickness with a temporal resolution of about one second. In this talk, we demonstrate our methodology with a model system involving silica microspheres, immersed in aqueous NaCl, with poly(ethylene oxide) homopolymer. The experiments resolve mass-transfer-limited adsorption and slower polymer reconformation dynamics up to full coverage.