研究人员开发出一种能导电也能感应水存在的纸，可以降低水渗漏产生的副作用,具体方法是在标准造纸过程中从制浆开始，控制木纤维，使其混合在纳米材料中 

    在城市和大型纸厂中，要找出复杂管道系统的漏水需要花费巨大的时间和精力。为了找出问题所在，技术工人必须把许多管件拆开。美国给水工程协会表示，美国每年有近250000条水管漏水，导致公共水设施每年损失大约28亿美元。
    华盛顿大学的一个团队发明出一种可以测出水的智能纸，从而希望简化找到漏水根源的过程。 这种用导电的纳米材料做蕾丝的纸，可以起开关的作用，开启或关闭LED灯，或者开启或关闭一种显示有水或无水的警报器。
    研究人员把他们的发现发表在材料化学杂志A11月刊的一篇文章中。
    华盛顿大学环境和森林科学院生物材料科学和工程学助理教授及首席作者安东尼.迪恰拉（Anthony Dichiara）说：“水的探测具有挑战性，因为水的极性，现在采用的办法既昂贵又不实际，这也是现在必须开展这项工作的原因。”
    生物材料科学和工程系的大学生团队与迪恰拉教授一起把纳米材料成功蕾丝到既能导电又能测试出水的纸中。他们从制浆开始，处理木纤维并按照标准造纸程序把木纤维与纳米材料混合在一起，但是之前这从未在敏感纸上用过。
    发现能测试出水的存在的纸纯粹出于偶然。水珠掉在团队发明的导电纸上，使led 显示灯显示导电并关闭。虽然最初他们以为把纸给毁了，研究人员发现他们不但没毁纸，反而发明出一种对水敏感的纸。
    水接触到纸时，纤维细胞比原来的大三倍。这种膨胀启动了纸里的导电纳米材料，它接着搅动电开关，使led灯关闭。
    这个过程完全可逆，随着纸变干，导电系统重塑，这样纸可以重复使用。
    研究人员的想像是，在工厂，把一张带电池的导电纸放在一根管子附近，或者放在相惯管的复杂网路之下。如果管子漏水，纸能够探测到水的出现，然后向中央控制中心发送无线电子信号，这样，工程人员就可以迅速确定漏水位置并予以修复。
    纸可以包裹在管子上，在此情况下来发现漏水。此外，纸非常敏感，还可以检测各种液体混合的水的微量。这种把同其它分子区分开来的能力对于石油和生物油领域尤为有价值，这里的水通常都不纯。
    往纸里添加的纳米材料的设计使其在传统造纸过程中，不用改动程序就可以混合进去。这些材料是用非常导电的碳做的。碳存在于所有生物中，它几乎是一种可以燃烧成木炭的自然材料。然后，可以提炼出碳原子来合成这些材料。研究团队试验过用香蕉皮，树皮绉，甚至动物粪便制作纳米材料。
    他们还尝试用木材边角料制作纳米材料，以证明造纸过程可以用便宜的自然材料完成。
    迪恰拉说：“现在我们有一个可持续程序，一切都来自浆、纸，我们可以用浆、纸制作导电材料。”
    纸的质地坚硬光滑，纳米材料（碳和木炭）使纸的颜色呈混黑色。实验室做的8英寸盘是样品；研发团队希望下一步在工业规模的纸机上测试程序，将会用到更多的纳米材料及纸浆。

Researchers developing paper that can conduct electricity and sense the presence of water, to mitigate effect of water line breaks; method starts with pulp, manipulates wood fibers to carefully mix in nanomaterials in standard papermaking process
        
  In cities and large-scale manufacturing plants, a water leak in a complicated network of pipes can take tremendous time and effort to detect, as technicians must disassemble many pieces to locate the problem. The American Water Works Association indicates that nearly a quarter-million water line breaks occur each year in the U.S., costing public water utilities about $2.8 billion annually.
  A University of Washington team wants to simplify the process for discovering detrimental leaks by developing “smart” paper that can sense the presence of water. The paper, laced with conductive nanomaterials, can be employed as a switch, turning on or off an LED light or an alarm system indicating the absence or presence of water.
  The researchers described their discovery in a paper appearing in the November issue of the Journal of Materials Chemistry A.
  “Water sensing is very challenging to do due to the polar nature of water, and what is used now is very expensive and not practical to implement,” said lead author Anthony Dichiara, a UW assistant professor of bioresource science and engineering in the School of Environment and Forest Sciences. “That led to the reason to pursue this work.”
Along with Dichiara, a team of UW undergraduate students in the Bioresource Science and Engineering program successfully embedded nanomaterials in paper that can conduct electricity and sense the presence of water. Starting with pulp, they manipulated the wood fibers and carefully mixed in nanomaterials using a standard process for papermaking, but never before used to make sensing papers.
Discovering that the paper could detect the presence of water came by way of a fortuitous accident. Water droplets fell onto the conductive paper the team had created, causing the LED light indicating conductivity to turn off. Though at first they thought they had ruined the paper, the researchers realized they had instead created a paper that was sensitive to water.
  When water hits the paper, its fibrous cells swell to up to three times their original size. That expansion displaces conductive nanomaterials inside the paper, which in turn disrupts the electrical connections and causes the LED indicator light to turn off.
  This process is fully reversible, and as the paper dries, the conductive network re-forms so the paper can be used multiple times.

  The researchers envision an application in which a sheet of conductive paper with a battery could be placed around a pipe or under a complex network of intersecting pipes in a manufacturing plant. If a pipe leaks, the paper would sense the presence of water, then send an electrical signal wirelessly to a central control center so a technician could quickly locate and repair the leak.
The paper could be wrapped around a pipe, as shown in this example, to detect leaks. In addition, the paper is so sensitive that it can also detect trace amounts of water in mixtures of various liquids. This ability to distinguish water from other molecules is particularly valuable for the petroleum and biofuel industries, where water is regarded as an impurity.
  The nanomaterials added to the paper were engineered in such a way that they can be incorporated during conventional papermaking without having to modify the process. These materials are made of extremely conductive carbon. Because carbon is found in all living things, nearly any natural material can be burned to make charcoal, and then carbon atoms can be extracted to synthesize the materials. The team has experimented with making nanomaterials from banana peels, tree bark and even animal feces.
  They also tried making nanomaterials from wood scraps to show that the entire papermaking process can be completed with cheap, natural materials.
  “Now we have a sustainable process where everything is from pulp and paper, and we can make conductive materials from them,” Dichiara said.
  The paper, stiff and smooth in texture, is a rich black color because of the nanomaterials (carbon from charcoal). The 8-inch disks made in the lab are prototypes; the team hopes to test the process on an industrial-sized papermaking machine next, which will require more nanomaterials and paper pulp.