Re: [Aroid-l] lotus effect with Colocasia fallax

From: Theodore Held <oppenhauser2001 at gmail.com> on 2011.01.21 at 18:16:29(21787) David, Yes, I find what you say is correct. In fact, if anyone would like to read about the phenomenon in depth, including the Pistia references, just Google >Barthlott Pistia< and you'll get a Google book page that describes what the Barthlott people found as well as quite a bit more information about superhydrophobicity. Thanks for the reference. Ted Held +More Detroit. On Tue, Jan 18, 2011 at 3:17 AM, david bröderbauer wrote: > Hi Ted, > > As far as I know it was the Barthlott-group in Germany who studied the > Pistia-leave under SEM. They showed that the hairs are coated with wax... > > David > >> Date: Sun, 16 Jan 2011 16:09:12 -0500 >> From: oppenhauser2001@gmail.com >> To: aroid-l@www.gizmoworks.com >> Subject: Re: [Aroid-l] lotus effect with Colocasia fallax >> >> David, >> >> I have no idea whether or not individual Pistia hairs are coated with >> some form of wax or whether the wetting by water of an individual hair >> is simply poor enough to provide a bridge for the droplet surface over >> to the next surface hair, which bridging prevents wicking of the water >> down into the hairy structure. >> >> This would be a good research topic: Dry some Pistia leaves and see >> what is extracted (meaning dissolved by some liquid, ordinarily >> followed by gentle drying to investigate the residual - Steve Lucas >> was right to insist on technical terms being defined) by solvent >> (hexane or toluene would be good solvent candidates for wax) and if it >> is indeed a waxy substance. If no one has done this I'll do it myself >> and report back to this forum. >> >> Another thing that might be of interest to aroiders is that the net >> result of Pistia hydrophobicity (which merely means its reluctance to >> be wetted by water, typically observed as a tendency for water on a >> hydrophobic surface to "bead up" into discrete droplets) is the >> extreme buoyancy of the species. Try to submerge one of these plants >> and it's almost like you are trying to submerge an air bubble. It is >> curious to me how insubstantial a Pistia leaf is. It looks big, but >> when compacted and dried there is almost nothing left. Much of the >> apparent volume is simply air. >> >> Ted Held >> Detroit. >> >> On Thu, Jan 13, 2011 at 7:53 AM, david bröderbauer >> wrote: >> > Hi Ted, >> > >> > Pistia is in fact a very beautiful example for a water-repellent >> > surface. It >> > has to be kept in mind - as you mention - that it generates this >> > superhydrophobic effect with hairs (not with papillate cells like in >> > Nelumbo >> > or Colocasia) that are covered with wax. So, the term 'lotus-effect' >> > describes the syndrom of superhydrophobicity (which means that the >> > contact >> > angle of a water droplet is at least 150°), but there are different >> > structures within the Araceae and other plant families, that produce >> > this >> > effect. >> > >> > David Broederbauer >> > >> >> Date: Wed, 12 Jan 2011 13:04:17 -0500 >> >> From: oppenhauser2001@gmail.com >> >> To: aroid-l@www.gizmoworks.com >> >> Subject: Re: [Aroid-l] lotus effect with Colocasia fallax >> >> >> >> Geneviève, >> >> >> >> The lotus effect is quite common in my experience. It has been getting >> >> a lot of attention in the popular press lately and there are a number >> >> of academic studies of the phenomenon using nano materials. A Google >> >> search will turn up many hits. >> >> >> >> One of the best displays can be seen on the humble aroid Pistia. >> >> Leaves of Pistia will support quite a large water droplet with no >> >> wetting of the leaf surface that supports the hairs. >> >> >> >> Ted Held. >> >> Detroit >> >> >> >> 2011/1/11 Geneviève Ferry : >> >> > Dear aroiders , >> >> > >> >> > Today, three students came looking leaves Colocasia fallax to >> >> > understand >> >> > the >> >> > phenomenon of superhydrobicity (lotus effect). >> >> > Do you have information on this phenomenon? >> >> > (Experience, etc. ....) >> >> > >> >> > Thank you for your help. >> >> > >> >> > Best wishes , >> >> > >> >> > Geneviève Ferry >> >> > _______________________________________________ >> >> > Aroid-L mailing list >> >> > Aroid-L@www.gizmoworks.com >> >> > http://www.gizmoworks.com/mailman/listinfo/aroid-l >> >> > >> >> > >> >> _______________________________________________ >> >> Aroid-L mailing list >> >> Aroid-L@www.gizmoworks.com >> >> http://www.gizmoworks.com/mailman/listinfo/aroid-l >> > >> > _______________________________________________ >> > Aroid-L mailing list >> > Aroid-L@www.gizmoworks.com >> > http://www.gizmoworks.com/mailman/listinfo/aroid-l >> > >> > >> _______________________________________________ >> Aroid-L mailing list >> Aroid-L@www.gizmoworks.com >> http://www.gizmoworks.com/mailman/listinfo/aroid-l > > _______________________________________________ > Aroid-L mailing list > Aroid-L@www.gizmoworks.com > http://www.gizmoworks.com/mailman/listinfo/aroid-l > > _______________________________________________ Aroid-L mailing list Aroid-L@www.gizmoworks.com http://www.gizmoworks.com/mailman/listinfo/aroid-l

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