In the laminar flow reactors that are common in microfluidic applications, rates of interfacial mass transfer tend toward constant, asymptotic values that are defined by diffusion across the characteristic dimension of the flow (i.e., Sh = O(1)). Our previous numerical work suggested that chaotically stirred laminar flows are uniquely good at avoiding this fate, such that the asymptotic rates remain dependent on the flow rate and can be made to be much larger than O(1). In this talk, we will present numerical and theoretical studies that extend this finding and clarify the role of chaotic advection in defining the transfer process. We will present experimental studies performed microfluidic electrochemical cells that validate these predictions. Finally, we will discuss general design considerations dictated by these findings for microfluidic fuel cells, surface-based sensors, and separation processes.