Interfacial self-transportation via controlled wettability transition for directed self-assembly

Wettability transition is a significant responsive mechanism which is widely applied to construct smart materials and systems. The broad-spectrum responsiveness of the wettability transition makes it a promising way to expand innovative applications. Here, we develop a track-guided self-transportation system mediated by sequential wettability transition accompanied with capillary transportation. Alkaline fuel is loaded into polydimethylsiloxane (PDMS) cuboid to trigger the wettability transition of distributed superhydrophobic tracks laid in shallow water. After the wettability transition, the induced capillary force can propel the repetitive track-to-track transportation of PDMS. Importantly, the spacing between adjacent tracks is rationally designed based on multiple factors including threshold of wettability transition, diffusion kinetics and capillary interaction. Furthermore, the track-guided transportation system is applied to realize directed self-assembly of multiple PDMS building blocks for designated configuration, which increases the complexity and intelligence of self-assembly systems.