The separator of a lithium-ion battery prevents the direct contact between the positive and negative electrodes while serving as the electrolyte reservoir to enable the transportation of lithium ions between the two electrodes.

This research examined the effects of timing, order and the durability of first mover advantages by analyzing the stock market reactions to new product introductions and imitations. The major findings are that both timing and order of moves are important and that rival reactions undermine the durability of first mover advantages. More specifically, (1) early and fast movers achieve greater gains than late and slow movers, and (2) first movers suffer at the time of new product imitations. Copyright © 2000 John Wiley & Sons, Ltd.

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Suitable pumping methods for flow control remain a major technical hurdle in the path of biomedical microfluidic systems for point-of-care (POC) diagnostics. A vacuum-driven power-free micropumping method provides a promising solution to such a challenge. In this review, we focus on vacuum-driven power-free microfluidics based on the gas solubility or permeability of polydimethylsiloxane (PDMS); degassed PDMS can restore air inside itself due to its high gas solubility or gas permeable nature. PDMS allows the transfer of air into a vacuum through it due to its high gas permeability. Therefore, it is possible to store or transfer air into or through the gas soluble or permeable PDMS in order to withdraw liquids into the embedded dead-end microfluidic channels. This article provides a comprehensive look at the physics of the gas solubility and permeability of PDMS, a systematic review of different types of vacuum-driven power-free microfluidics, and guidelines for designing solubility-based or permeability-based PDMS devices, alongside existing applications. Advanced topics and the outlook in using micropumping that utilizes the gas solubility or permeability of PDMS will be also discussed. We strongly recommend that microfluidics and lab-on-chip (LOC) communities harness vacuum energy to develop smart vacuum-driven microfluidic systems.

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