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Researchers developing paper that can conduct electricity and sense the presence of water, to mitigate effect of water line breaks
发布者(Posted by):浆纸商务网时间(Time):2017-12-01 08:58


    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。
    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。”
    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。

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.

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