Microfluidics Lab, Department of Aerospace and Mechanical Engineering, University of Liège, Belgium.
Published: January 2020
AI Article Synopsis
Article Abstract
We propose a new 3D-printed capillary gripper equipped with a textured surface for motion-free release. The gripper classically picks up micro-objects thanks to the capillary forces induced by a liquid bridge. Micro-objects are released by decreasing the volume of this bridge through evaporation. The latter can be either natural or speeded up by a heating source (an IR laser or the Joule effect). The volume reduction changes the conformity of the contact between the gripper and the object. We analyze the gripper performance and the capillary force generated, and then we rationalize the release mechanism by defining the concept of contact conformity in the context of capillary forces.
Despite the importance of the effect of subnanoscale roughness on contact line behavior, it is difficult to directly observe the local behavior of contact lines at the micro- and nanoscale, leaving significant gaps in our current understanding. In this research, we investigate contact line motions and their relationship with nanoscale surface topography using coherence scanning interferometry. Our experiments were conducted on the substrates with different wettability without changing nanoscale surface topography.
Copper and its alloys with transition metals (as good conductors of electricity and heat) are extensively used in electrical industry, electronics, and cooling systems and can be the subject of surface degradation by oxidation. In certain circumstances, surface degradation of copper occurs catastrophically. Predicting catastrophic oxidation kinetics and developing protective technology require understanding the mass transfer mechanisms in the solid/liquid/gas composite scale formed on the copper surface during catastrophic degradation.
State Key Laboratory of Structural Analysis, Optimization and CAE Software for Industrial Equipment, National Engineering Research Center for Advanced Polymer Processing Technology, Zhengzhou University, Zhengzhou, 450002, China.
Aerogel fibers uniting characteristics of both aerogels (lightweight and porosity) and fibers (flexibility and wearability) exhibit a great potential for the production of the next generation of thermal protection textiles; still, the complex drying procedures and mechanical brittleness remain the main obstacles toward further exploitation. Herein, flexible and robust aramid nanofiber aerogel fibers (ANAFs) are scalably prepared by continuous wet-spinning coupled with fast air-drying. This synthesis involves calcium ions (Ca⁺) cross-linking and solvent displacement by low surface tension solvents, to enhance skeleton strength and reduce the capillary force during evaporation, respectively, thus minimizing shrinkage to 29.
Numerous organisms exploit asymmetrical capillary forces generated by unique fiber or asymmetrical tapered structures to rapidly eliminate undesired liquid for survival in moist or rainy habitats. Human eyelashes, the primary protector of eyes, use a yet-to-be-fully-understood mechanism to efficiently transfer incoming liquid for vision safeguarding. Here, we elucidate that human eyelashes featuring a hydrophobic curved flexible fiber array with surface micro-ratchet and macro-curvature approximating the is adept at directionally and rapidly expelling incoming liquid to maintain clear vision.
Sorption processes are critical for the drying and durability of cement-based materials, directly affecting their thermal properties. Temperature can substantially influence these processes. This work uses molecular simulations to study sorption in C-S-H pores under varying temperatures and relative humidity, considering pore sizes from the gel to the interlayer scale (between 11.
