Polydopamine (PDA) particulates collected from used solutions were applied for preparing surfaces with special wetting behaviors. PDA/Ag microparticles with hierarchical structures were achieved by reduction. On one hand, fluorinated PDA/Ag particles obtained superhydrophobic ability which could withstand variable pHs. On the other hand, PDA/Ag particles modified with mixed thiols could converse from superhydrophobic to superhydrophilic due to pH variation. The results not only indicate the as-formed microparticles could find wide application in oil/water separation, liquid regulation and indicators, but also show one of many possible ways to exploit the use of recycled PDA. (C) 2016 Elsevier B.V. All rights reserved.