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'''Dry glue''' is an [[adhesion]] product based upon the [[adaptation]]s of [[gecko]]s' feet that allow them to climb sheer surfaces such as vertical glass. Synthetic equivalents use [[carbon nanotube]]s as [[synthetic setae]] on reusable adhesive patches.
{{lead too short|date=July 2010}}
'''Dry glue''' is a method of adhesion based upon the naturally occurring adaptations of the feet of [[gecko]]s, which allow them to climb sheer surfaces, and even glass walls.
==Background==
[[Image:Gecko Leaftail 1.jpg|thumb|right|300px|[[Gecko]] climbing glass using its natural [[seta]]]]
A gecko can hang on a glass surface using only one toe. This ability of geckos has beenis attributed to [[van der Waals force]],<ref>{{Cite web |url=http://www.clemson.edu/newsroom/articles/2009/august/geckos.php5 |title=Researchers discover how geckos know when to hold tight<!-- Bot generated title --> |access-date=2009-11-08 |archive-date=2010-06-11 |archive-url=https://web.archive.org/web/20100611153743/http://www.clemson.edu/newsroom/articles/2009/august/geckos.php5 |url-status=dead }}</ref><ref>{{cite journal | last1 = Autumn | first1 = Kellar | authorlink2 author-link2= Metin Sitti | last2 = Sitti | first2 = Metin | last3 = Liang | first3 = Yiching A. | last4 = Peattie | first4 = Anne M. | last5 = Hansen | first5 = Wendy R. | last6 = Sponberg | first6 = Simon | last7 = Kenny | first7 = Thomas W. | last8 = Fearing | first8 = Ronald | last9 = Israelachvili | first9 = Jacob N. ''et al|last10=Full|first10=R.'' J.| year = 2002 | title = Evidence for van der Waals adhesion in gecko setae | url = | journal = Proceedings of the National Academy of Sciences of the USA | volume = 99 | issue = 19| pages = 12252–12256 | doi = 10.1073/pnas.192252799 | pmid = 12198184 | pmc = 129431 |bibcode = 2002PNAS...9912252A |display-authors=3|doi-access=free}}</ref> although a more recent study suggests that water molecules of roughly monolayer thickness (present on virtually all natural surfaces) also play a role.<ref>{{cite journal | last1 = Huber | first1 = G. | last2 = Mantz | first2 = H. | last3 = Spolenak | first3 = R. | last4 = Mecke | first4 = K. | last5 = Jacobs | first5 = K. | last6 = Gorb | first6 = S. N. | last7 = Arzt | first7 = E. | year = 2005 | title = Evidence for capillarity contributions to gecko adhesion from single spatula nanomechanical measurements | url = | journal = Proceedings of the National Academy of Sciences of the USA | volume = 102 | issue = 45| pages = 16293–16296 | doi = 10.1073/pnas.0506328102 | pmid = 16260737 | pmc = 1283435 |bibcode = 2005PNAS..10216293H |doi-access=free}}</ref>
==Developments==
In 2007, researchers from the [[University of Akron]] and [[Rensselaer Polytechnic Institute]] announced they had developed a form of flexible, reusable [[gecko tape]] using [[carbon nanotube]]s to create microscopic [[synthetic setae]] and [[spatula]]e capable of supporting a [[shear stress]] of 32 [[Newton (unit)|N]]/[[Metre|cm]]<sup>2</sup>, which is four times the strength of a gecko's foot.<ref>{{Cite journal
===University of Akron and the Rensselaer Polytechnic Institute===
| last1 = Ge | first1 = L.
Researchers announced in a paper published in the June 18–22, 2007 issue of the ''Proceedings of the National Academy of Sciences'' that using this technique they have created a synthetic “gecko tape” with four times the sticking power of a natural gecko foot.<ref>[http://www.physorg.com/news101460241.html Nanotube adhesive sticks better than a gecko's foot], ''PhysOrg.com'' retrieved 7 July 2007</ref> Particularly effective has been a checkerboard carpet of this material, which can be peeled and re-adhered repeatedly without weakening.<ref>http://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=112442&org=NSF</ref><ref>{{Cite web |author=Will Knight |title=Gecko-like robot scampers up the wall |url=http://www.newscientist.com/news/news.jsp?id=ns99993785 |date=2003-06-01 |archiveurl=http://web.archive.org/web/20071213181425rn_1/www.newscientist.com/article.ns?id=dn3785 |archivedate=2007-12-13 |work=[[New Scientist]] |accessdate=2009-05-02 |postscript=<!-- Bot inserted parameter. Either remove it; or change its value to "." for the cite to end in a ".", as necessary. -->{{inconsistent citations}} }} Cites {{cite journal|doi=10.1038/nmat917|title=Microfabricated adhesive mimicking gecko foot-hair|year=2003|last1=Geim|first1=A. K.|last2=Dubonos|first2=S. V.|last3=Grigorieva|first3=I. V.|last4=Novoselov|first4=K. S.|last5=Zhukov|first5=A. A.|last6=Shapoval|first6=S. Yu.|journal=Nature Materials|volume=2|issue=7|pages=461–463|pmid=12776092|bibcode=2003NatMa...2..461G}}</ref><ref>http://www.uakron.edu/news/articles/uamain_1293.php</ref> The material is made of columns of [[carbon nanotubes]] rooted in pieces of flexible polymer. The nanotubes were grown on a silicon base and then transferred to the polymer to provide a flexible base, similar to a gecko's foot. When dried, the polymer holds the silicon base, which in turn, holds the nanotubes.
| last2 = Sethi | first2 = S.
| last3 = Ci | first3 = L.
| last4 = Ajayan | first4 = P. M.
| last5 = Dhinojwala | first5 = A.
| title = Carbon nanotube-based synthetic gecko tapes
| doi = 10.1073/pnas.0703505104
| journal = Proceedings of the National Academy of Sciences
| volume = 104
| issue = 26
| pages = 10792–10795
| year = 2007
| pmid = 17578915
| pmc =1904109
|bibcode = 2007PNAS..10410792G | doi-access = free
}}</ref>
In 2008 researchers from the [[University of Dayton]] reported a gecko glue capable of supporting 100N/cm<sup>2</sup>, ten times the strength generated by a gecko's foot. The research also used carbon nanotubes, but included a curled end which allowed stronger binding but easy removal.<ref>{{Cite journal
===Stanford University and Carnegie Mellon University===
| last1 = Qu | first1 = L.
In 2006, researchers at [[Stanford University]] and [[Carnegie Mellon University]] developed a gecko-like [[robot]] which uses [[synthetic setae]] to mount walls.<ref>{{Cite document |title=Gecko-like robot scampers up the wall |url=http://www.newscientisttech.com/channel/tech/mg19025526.500.html |date=2006-05-23 |archiveurl=http://web.archive.org/web/20071216191024/technology.newscientist.com/channel/tech/mg19025526.500.html |archivedate=2007-12-16 |publisher=[[New Scientist]] |issue=2552 |pages=29 |accessdate=2009-05-02 |postscript=<!-- Bot inserted parameter. Either remove it; or change its value to "." for the cite to end in a ".", as necessary. -->{{inconsistent citations}}}}</ref>
| last2 = Dai | first2 = L.
| last3 = Stone | first3 = M.
| last4 = Xia | first4 = Z.
| last5 = Wang | first5 = Z. L.
| title = Carbon Nanotube Arrays with Strong Shear Binding-On and Easy Normal Lifting-Off
| doi = 10.1126/science.1159503
| journal = Science
| volume = 322
| issue = 5899
| pages = 238–242
| year = 2008
| pmid = 18845750
|bibcode = 2008Sci...322..238Q | s2cid = 9597020
}}</ref> [[DARPA|Defense Advanced Research Projects Agency]] (DARPA) has a project called "Z-Man" that is attempting to develop a fabric allowing soldiers to scale vertical walls while carrying a full combat load.<ref>{{cite web | url = http://www.darpa.mil/our_work/DSO/programs/Z_man.aspx | title = Z-man | publisher = [[DARPA]] | access-date = 2012-07-27 | last = Goodman | first = M | url-status = dead | archive-url = https://web.archive.org/web/20120806163801/http://www.darpa.mil/Our_Work/DSO/Programs/Z_Man.aspx | archive-date = 2012-08-06 }}</ref> In February 2012 [[Nitto Denko]] developed a version of gecko tape capable of sticking at temperatures between -150 and 500°[[Celsius|C]].<ref>{{cite press release|title=Nitto Denko's "Gecko Tape" achieves precise, contamination-free analysis service in the -150- 500°C range | publisher = [[Nitto Denko]] | date = 2012-02-24 | access-date = 2012-07-27 | url = http://www.nitto.com/news/20120224/index.html }}</ref>
==See also==
===Georgia Institute of Technology in Atlanta===
* [[Gecko adhesion]]
On October 9, 2008, the discovery of a new type of dry glue designed to mimic gecko feet was announced. The glue is 10 times stickier than that of the gravity-defying lizards, and three times stickier than other gecko-inspired glues. [[Liming Dai]] of the [[University of Dayton]] said "It's the stickiest dry glue yet".<ref>[http://www.reuters.com/article/scienceNews/idUSN0942431020081009?sp=true Gecko-like glue is said to be stickiest yet], "reuters.com" 8 October 2008</ref>
* [[Gecko tape]]
* [[Synthetic setae]]
===Defense Advanced Research Projects Agency===
{{Unreferenced section}}
DARPA (Defense Advanced Research Projects Agency) is also currently working on this technology to enable a soldier to scale a wall at .5 m/s{{Cn}}. This project is named Z-Man. Experiments are currently under way to develop nano-adhesives using the van der Waals effect.
==References==
{{Reflist}}
==External links==
{{DEFAULTSORT:Dry Glue}}
*[https://www.deepmateriales.com/ Semiconductor Adhesives]
[[Category:Adhesives]]
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