Chemistry and Physics of Materials Unit and Thematic Unit on Nanochemistry, Jawaharlal Nehru Centre for Advanced Scientific Research , Bangalore 560064, India.
Supramolecular Chemistry Laboratory, New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research , Bangalore 560064, India.
ACS Appl Mater Interfaces. 2017 Sep 20;9(37):32065-32070. doi: 10.1021/acsami.7b10732. Epub 2017 Sep 11.
Memorizing the magnitude of a physical parameter such as relative humidity in a consignment may be useful for maintaining recommended conditions over a period of time. In relation to cost and energy considerations, it is important that the memorizing device works in the unpowered passive state. In this article, we report the fabrication of a humidity-responsive device that can memorize the humidity condition it had experienced while being unpowered. The device makes use of supramolecular nanofibers obtained from the self-assembly of donor-acceptor (D-A) molecules, coronene tetracarboxylate salt (CS) and dodecyl methyl viologen (DMV), respectively, from aqueous medium. The fibers, while being highly sensitive to humidity, tend to develop electrically induced disorder under constant voltage, leading to increased resistance with time. The conducting state can be regained via self-assembly by exposing the device to humidity in the absence of applied voltage, the extent of recovery depending on the magnitude of the humidity applied under no bias. This nature of the fibers has been exploited in reading the humidity memory state, which interestingly is independent of the lapsed time since the humidity exposure as well as the duration of exposure. Importantly, the device is capable of differentiating the profiles of varying humidity conditions from its memory. The device finds use in applications requiring stringent condition monitoring.
记忆一批货物中物理参数（如相对湿度）的大小，对于在一段时间内维持推荐条件可能是有用的。考虑到成本和能源因素，记忆装置在无电源的无源状态下工作非常重要。在本文中，我们报告了一种湿度响应装置的制造，该装置可以记忆其在无电源状态下经历的湿度条件。该装置利用了从供体-受体（D-A）分子、蔻酸四羧酸盐（CS）和十二烷基甲基紫精（DMV）在水溶液中自组装得到的超分子纳米纤维。这些纤维对湿度非常敏感，但在恒压下容易发生电诱导无序，导致电阻随时间增加。通过在没有施加电压的情况下将器件暴露于湿度中，可以通过自组装恢复导电状态，恢复的程度取决于无偏压下施加的湿度的大小。这种纤维的性质被用于读取湿度记忆状态，有趣的是，这种状态与湿度暴露后的时间以及暴露的持续时间无关。重要的是，该器件能够从其记忆中区分出不同湿度条件的曲线。该器件可用于需要严格条件监测的应用。
