New super-bouyant material: Life preserver might float a horse

Here's a story that might float your boat: Researchers in China are reporting the development of miniature super-bouyant boats that float so well that an ordinary life preserver made from the same material might support a horse without sinking.

The advance, they say, might be difficult to apply to full-size craft. However, it could lead to a new generation of aquatic robots for spy missions and other futuristic devices, the scientists add. Their study is reported in ACS Applied Materials & Interfaces, a monthly journal.

In the new study, Qinmin Pan and Min Wang note that researchers have studied the chemistry of surfaces for years in an effort to design novel drag-reducing and fast-moving aquatic and air devices, such as boats and planes. Scientists have often turned to nature for inspiration. One source: The water strider, whose highly water-repellant (superhydrophobic) legs allow this insect to literally scoot across water surfaces at high speeds. But researchers still have not found a practical way to apply this phenomenon to technology.

Pan and Wang made several miniature boats about the size of a postage stamp. They used copper mesh treated with silver nitrate and other substances to make the boats’ surfaces superhydrophobic. When compared to similar copper boats made without the novel surfaces, the water repellant boats floated more smoothly and also showed a surprisingly large loading capacity. The best performing mini-boat floated with up to two times its maximum projected loading-capacity, the scientists say. “Interestingly, the boat is able to keep floating even if its upper edges are below the water surface,” the scientists note.

More information: "Miniature Boats with Striking Loading Capacity Fabricated from Superhydrophobic Copper Meshes" Applied Materials & Interfaces

Provided by ACS

   

• barakn - Mar 12, 2009
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  It sounds to me like they are claiming that they can float something weighing more than the weight of the water displaced by the object. This might be true considering that they are relying on surface tension to do it, but this is not going to scale up to a larger size. Since horses can already float (and swim), the claim that a life preserver could float one is meaningless. An ordinary styrofoam packing peanut could float a horse.
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• KaiKonn - Mar 15, 2009
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  @barakn. I read the articles on this site daily, sometimes more than once per day. I've been doing it for over a year, have never posted a single comment, and expected not to do so for the foreseeable future. However, after reading your comment I simply could not allow a statement such as yours to go without a retort. While it is true, that a horse can swim, and can float to some degree, I feel as though you completely missed the spirit of the article. It is people such as yourself, who "pop off" with comments such as yours that give people like myself, and others who understand concepts, or at a minimum are capable of extrapolating the conceptual context of an article, a bad taste in their mouth. Not only are your statements primarily without merit, you completely missed the spirit of the article. You are obviously lacking in the capacity to understand the inferences made in the article. Obviously, the article refers to the capability of the material to support large amounts of weight, and that a small amount of it approximately the size of a standard life preserver, could float the weight of a horse (between 900 and 1100 pounds on average). Please, refrain from making comments disparaging the content or context of a message without at a minimum taking into consideration the spirit / inference of the article. Look a bit beyond the words of the article, and consider its message.
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• smiffy - Mar 16, 2009
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  It sounds to me like they are claiming that they can float something weighing more than the weight of the water displaced by the object. This might be true considering that they are relying on surface tension to do it, but this is not going to scale up to a larger size

  I can't see any reason why this effect should not be scaled up, though that's a bit academic since this thing is unlikely to be robust enough for any practical use.
  
  Firstly, any motion through the water might unbalance the effect in one direction causing instability.
  
  Secondly, if the vessel (or life jacket) ever tips over, the hygrophopic surfaces would act the other way and sink it.
  
  
  
  Intriguing though. If the stability problems could be overcome then there should be no practical limit to the amount of weight the platform could support, providing there was sufficient depth of water.
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• jselin - Mar 31, 2009
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  @ smiffy
  
  

  Secondly, if the vessel (or life jacket) ever tips over, the hygrophopic surfaces would act the other way and sink it.

  
  
  If what you're saying was true we'd have hydrophobic propulsion. You'd just get a pretty air pocket stuck to the surface and sinking would proceed as normal.
  
  

  Intriguing though. If the stability problems could be overcome then there should be no practical limit to the amount of weight the platform could support, providing there was sufficient depth of water.

  
  
  Based on what? If I put a coffee cup on a water strider, both would sink. The additional weight bearing capacity is due to surface tension. The ultimate load would likely be dependant on the area and radius of contact.
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• smiffy - Apr 01, 2009
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  You're right. I hadn't thought the post through. I believed that the effect was something different from ordinary surface tension; due I think to the article claiming that the effect persisted with the upper edges of the boat below the surface of the water, which I took to mean that it was submerged. It's clear from the picture in their original paper that all that's taking place is buoyancy due to surface tension and a cushion of trapped air. As such, as soon as the surface skin of the water is broken the boat is bound to sink.
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