Active porous transition towards spatiotemporal control of molecular flow in a crystal membrane.

Yuichi Takasaki,Satoshi Takamizawa

doi:10.1038/ncomms9934

Abstract

Fluidic control is an essential technology widely found in processes such as flood control in land irrigation and cell metabolism in biological tissues. In any fluidic control system, valve function is the key mechanism used to actively regulate flow and miniaturization of fluidic regulation with precise workability will be particularly vital in the development of microfluidic control. The concept of crystal engineering is alternative to processing technology in microstructure construction, as the ultimate microfluidic devices must provide molecular level control. Consequently, microporous crystals can instantly be converted to microfluidic devices if introduced in an active transformability of porous structure and geometry. Here we show that the introduction of a stress-induced martensitic transition mechanism converts a microporous molecular crystal into an active fluidic device with spatiotemporal molecular flow controllability through mechanical reorientation of subnanometre channels.

Highlights

Fluidic control is an essential technology widely found in processes such as flood control in land irrigation and cell metabolism in biological tissues
Fluid transportation can be seen in a wide range of processes, from irrigation to biological tissues such as flood control or cell metabolism, through programmed pathways with adequate motive force to generate flow
The scale and means used in fluidic control depend on purpose, the valve function that controls the directivity and mass rate of flow is a key mechanism to actively regulate flow in any fluidic transportation operation

Summary

Introduction

Fluidic control is an essential technology widely found in processes such as flood control in land irrigation and cell metabolism in biological tissues. We show that the introduction of a stress-induced martensitic transition mechanism converts a microporous molecular crystal into an active fluidic device with spatiotemporal molecular flow controllability through mechanical reorientation of subnanometre channels. Towards the theoretically finest flow control, microporous solids seem to have the fundamental requirements for such the miniature devices They could immediately convert into attractive ‘nanofluidic’ devices if some sort of molecular flow controllability is embedded in them. We report a microporous crystal with superelasticity that actively controls accurate molecular flow by means of channel rearrangement. The generation of the a0 phase can change the direction of gas permeation by mechanical twinning and the width or number of channels in the generated a0 domains are precisely regulated by the shear range of the mother a crystal, as shown in Fig. 2c–f and Supplementary Fig. 5. A finer flux control in molecular scale can be realized by minimizing the a0 domain to a nanometre scale or by using additive slits or masks on a crystal a

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