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

From: =?iso-8859-1?B?ZGF2aWQgYnL2ZGVyYmF1ZXI=?= <david_dav44 at hotmail.com> on 2011.01.18 at 08:17:38 Hi Ted=2C 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 >=3B Date: Sun=2C 16 Jan 2011 16:09:12 -0500 >=3B From: oppenhauser2001@gmail.com >=3B To: aroid-l@www.gizmoworks.com >=3B Subject: Re: [Aroid-l] lotus effect with Colocasia fallax >=3B >=3B David=2C >=3B >=3B I have no idea whether or not individual Pistia hairs are coated with >=3B some form of wax or whether the wetting by water of an individual hair >=3B is simply poor enough to provide a bridge for the droplet surface over >=3B to the next surface hair=2C which bridging prevents wicking of the water >=3B down into the hairy structure. >=3B >=3B This would be a good research topic: Dry some Pistia leaves and see >=3B what is extracted (meaning dissolved by some liquid=2C ordinarily >=3B followed by gentle drying to investigate the residual - Steve Lucas >=3B was right to insist on technical terms being defined) by solvent >=3B (hexane or toluene would be good solvent candidates for wax) and if it >=3B is indeed a waxy substance. If no one has done this I'll do it myself >=3B and report back to this forum. >=3B >=3B Another thing that might be of interest to aroiders is that the net >=3B result of Pistia hydrophobicity (which merely means its reluctance to >=3B be wetted by water=2C typically observed as a tendency for water on a >=3B hydrophobic surface to "bead up" into discrete droplets) is the >=3B extreme buoyancy of the species. Try to submerge one of these plants >=3B and it's almost like you are trying to submerge an air bubble. It is >=3B curious to me how insubstantial a Pistia leaf is. It looks big=2C but >=3B when compacted and dried there is almost nothing left. Much of the >=3B apparent volume is simply air. >=3B >=3B Ted Held >=3B Detroit. >=3B >=3B On Thu=2C Jan 13=2C 2011 at 7:53 AM=2C david br=F6derbauer >=3B <=3Bdavid_dav44@hotmail.com>=3B wrote: >=3B >=3B Hi Ted=2C >=3B >=3B >=3B >=3B Pistia is in fact a very beautiful example for a water-repellent surface. It >=3B >=3B has to be kept in mind - as you mention - that it generates this >=3B >=3B superhydrophobic effect with hairs (not with papillate cells like in Nelumbo >=3B >=3B or Colocasia) that are covered with wax. So=2C the term 'lotus-effect' >=3B >=3B describes the syndrom of superhydrophobicity (which means that the contact >=3B >=3B angle of a water droplet is at least 150=B0)=2C but there are different >=3B >=3B structures within the Araceae and other plant families=2C that produce this >=3B >=3B effect. >=3B >=3B >=3B >=3B David Broederbauer >=3B >=3B >=3B >=3B>=3B Date: Wed=2C 12 Jan 2011 13:04:17 -0500 >=3B >=3B>=3B From: oppenhauser2001@gmail.com >=3B >=3B>=3B To: aroid-l@www.gizmoworks.com >=3B >=3B>=3B Subject: Re: [Aroid-l] lotus effect with Colocasia fallax >=3B >=3B>=3B >=3B >=3B>=3B Genevi=E8ve=2C >=3B >=3B>=3B >=3B >=3B>=3B The lotus effect is quite common in my experience. It has been getting >=3B >=3B>=3B a lot of attention in the popular press lately and there are a number >=3B >=3B>=3B of academic studies of the phenomenon using nano materials. A Google >=3B >=3B>=3B search will turn up many hits. >=3B >=3B>=3B >=3B >=3B>=3B One of the best displays can be seen on the humble aroid Pistia. >=3B >=3B>=3B Leaves of Pistia will support quite a large water droplet with no >=3B >=3B>=3B wetting of the leaf surface that supports the hairs. >=3B >=3B>=3B >=3B >=3B>=3B Ted Held. >=3B >=3B>=3B Detroit >=3B >=3B>=3B >=3B >=3B>=3B 2011/1/11 Genevi=E8ve Ferry <=3Bjpcferry2@wanadoo.fr>=3B: >=3B >=3B>=3B >=3B Dear aroiders =2C >=3B >=3B>=3B >=3B >=3B >=3B>=3B >=3B Today=2C three students came looking leaves Colocasia fallax to understand >=3B >=3B>=3B >=3B the >=3B >=3B>=3B >=3B phenomenon of superhydrobicity (lotus effect). >=3B >=3B>=3B >=3B Do you have information on this phenomenon? >=3B >=3B>=3B >=3B (Experience=2C etc. ....) >=3B >=3B>=3B >=3B >=3B >=3B>=3B >=3B Thank you for your help. >=3B >=3B>=3B >=3B >=3B >=3B>=3B >=3B Best wishes =2C >=3B >=3B>=3B >=3B >=3B >=3B>=3B >=3B Genevi=E8ve Ferry >=3B >=3B>=3B >=3B _______________________________________________ >=3B >=3B>=3B >=3B Aroid-L mailing list >=3B >=3B>=3B >=3B Aroid-L@www.gizmoworks.com >=3B >=3B>=3B >=3B http://www.gizmoworks.com/mailman/listinfo/aroid-l >=3B >=3B>=3B >=3B >=3B >=3B>=3B >=3B >=3B >=3B>=3B _______________________________________________ >=3B >=3B>=3B Aroid-L mailing list >=3B >=3B>=3B Aroid-L@www.gizmoworks.com >=3B >=3B>=3B http://www.gizmoworks.com/mailman/listinfo/aroid-l >=3B >=3B >=3B >=3B _______________________________________________ >=3B >=3B Aroid-L mailing list >=3B >=3B Aroid-L@www.gizmoworks.com >=3B >=3B http://www.gizmoworks.com/mailman/listinfo/aroid-l >=3B >=3B >=3B >=3B >=3B _______________________________________________ >=3B Aroid-L mailing list >=3B Aroid-L@www.gizmoworks.com >=3B http://www.gizmoworks.com/mailman/listinfo/aroid-l --_aa692191-b8cf-4caa-b1b8-768e807972f4_-- --===============2225912303437619595==

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