The mechanical strength and interfacial behavior have been of great significance for composite membranes. In this work, an in-situ nano-indentation/scratch technique was employed to probe mechanical properties and interfacial adhesion of ceramic-supported polydimethylsiloxane (PDMS) composite membranes. The nanostructures of active, transition and support layers were systematically correlated with measured mechanical and adhesive properties, as well as interfacial morphologies and separation performance. It was found that the PDMS layer's mechanical strength was reinforced by the ceramic substrate and its elastic recovery could be promoted with the existence of PDMS-ceramic transition layer. The interfacial adhesion between PDMS layer and ceramic support can be remarkably enhanced with a critical load from 10 mN to > 50 mN, by increasing the PDMS thickness within 314 pm. During long-term Lest in continuous practical separation process, the optimized PDMS composite membrane exhibited excellent and stable performance and interfacial adhesion: total flux of 1244 g/m(2) h, butanol separation factor of 29.9 and critical load of 37 mN. (C) 2015 Elsevier B.V. All rights reserved.