Many natural creatures have demonstrated unique abilities in directional liquid transport (DLT) for better adapting to the local environment, which, for a long time, have inspired the material fabrication for applications in microfluidics, self-cleaning, water collection, etc. Recently, DLTs aroused by the corner effect have been witnessed in various natural organisms, where liquid transports/spreads spontaneously along the corner structures in microgrooves, wedges or conical structures driven by micro-/nano- scaled capillary forces without external energy input. Particularly, these DLTs show advantages of ultrahigh speed, continuous proceeding, and/or external controllability. Here, we reviewed recent research advances on the bioinspired DLTs induced by the corner effect, as well as the involved mechanisms and the artificial counterpart materials with various applications. We also introduced some bioinspired materials that are capable of stimulus-responsive DLT under external fields. Finally, we suggested perspectives of the bioinspired DLTs in liquid manipulations.

As a traditional writing instrument for calligraphy and painting, the Chinese brush has enjoyed a high reputation over the last 5, 000 years due to its ability to controllably handle liquid ink, and has been widely used to deposit ink into certain characters or figures as a means of cultural communication. In this mini-review, we first show how the key to the controllable liquid transfer in a Chinese brush lies in the anisotropic multi-scale structural features of the freshly emergent hairs. Then, drawing inspiration from this, applications in controllable liquid pumping, highly efficient liquid transfer and template-free printing microlines are addressed. We envision that the fundamentals of Chinese brushes and their applications in liquid manipulation mentioned in this review may also be extended to other liquid phase functional material systems.