Barczewski, M.

Barthlott, W.

Bohn, H.

Brede, M.

Kaltenmaier, A.

Koch, K.

Leder, A.

Schimmel, T.

Walheim, S.

Weis, A.

KITopen

M i th t dh i t t f bi l i leasur ng e wa er a es on on s ruc ures o o og ca        i t i i fa r-re a n ng sur aces A W i 1 A k K lt i 1 M tthi B ki1 St f W lh i 1 K ti K h4 M ti B d 3 Alf d L d 3aron e s , n e a enma er , a as arczews , e an a e m , ers n oc , ar n re e , re  e er ,     Holger Bohn2 Wilhelm Barthlott2 and Thomas Schimmel1 ,  ,    1 Institute of Applied Physics Institute of Nanotechnology and Center for Functional Nanostructures (CFN) Karlsruhe Institute of Technology (KIT).    ,   ,      ,     , 76021 K l h G ar sru e, ermany2. Nees-Institut for Biodiversity of Plants, University of Bonn, Meckenheimer Allee 170, 53115 Bonn, Germany3 Lehrstuhl Strömungsmechanik Fakultät für Maschinenbau und Schiffstechnik University of Rostock Albert-Einstein-Straße 2 18059 Rostock Germany.  ,     ,   ,  ,  , 4 Biologie und Nanobiologie Hochschule Rhein Waal Landwehr 4 47533 Kleve Germany.   ,  - ,  ,  , I t d ti D i th dn ro uc on: ye ng me oSuperhydrophobic technical surfaces are of high scientific and economic interest Salvinia untreated          because of their remarkable properties However in plants (e g Lotus) and    . ,   . .   i l hi hl ffi i t f h b l d [1 2] U t th t One method to an ma s g y e c en  sur aces ave een evo ve  , . p o now e mos  distinguish betweenattention was given to superhydrophobicity and self-cleaning properties.   h d hili ti dNevertheless air-retaining properties under water are of great technological y rop c ps an  ,        , economic and ecological interest e g for low friction fluid transport and drag super-hydrophobic rest    , . .        is to use dyesreducing ship coatings [3].    F thi th l f ior s, e ea  s Technical surfaces developed so far, mimicking the Lotus surface lack of their dipped in dyed water            limited persistence of air retention [4] In case of the water fern Salvinia we found    and imaged afterwards     .         d th t ff l h i t t bili th i l h d hili ti  a para ox a  o ers a nove  mec an sm o s a ze e a r- ayer: y rop c ps The areas that stay in on otherwise superhydrophobic hairs [5]. In order to understand this stabilization contact with the watereffect one has to measure the water adhesion of those structures However    become dyed here          . , those surfaces are chemically heterogeneous and topographically structured ,  f h b h       . parts o  t e ranc es Rhodamin B ith t i iRhodamin Bft i iHence, it is demanding to determine their surface energy, i.e. the water adhesion. and the tipsw ou  r ns ng a er r ns ngHere we show a novel method to determine the water adhesion on those  I d t             surfacesn a secon  s ep we . rinsed the dyed leaf [1] Barthlott W and Neinhuis C (1997) Planta 202 1-8 with clear water and      .  , .[2] Koch K and Barthlott W (2009) Phil Trans R Soc A 367 1487 1509    imaged it again      . . . . .  , - .[3] Corbett J J Koehler H W (2003) Geophysical Research 108 4650     ,     .  . , .[4] B l b i A K Mill A C R di i ti O K (2004) AIAA 42 411 414 While some patches of a asu raman an  , er  , e n o s   .  , - .[5] B thl tt W S hi l Th Wi h S K h K B d M B ki M W lh i S     the braches are dyed ar o  , c mme  , ersc  , oc  , re e , arczews  , a e m ,     b f th i i tWeis A, Kaltenmaier A, Leder A and Bohn H F (2010). e ore e r ns ng oo, Advanced Materials 22, 2325-2328, (cover article). only the tips stayed dyed after the rinsingHematoxylinHematoxylin    after rinsingwithout rinsingHierarchically structured surface of 100 µm    Salvinia molesta  U id f th fl ti l f S l i ipper s e o  e oa ng eaves o  a v n a molesta is densely covered with complex multicellular hairs Hairs branch and form egg-beater like structures with a total height of up to 2 mm         S h d h bi f i d luper- y rop o c sur ace s ense y M th d f d t i i th ff di tcovered with nanostructured wax crystals e o  or e erm n ng e snap-o  s anceTerminal cells lack wax crystals and After the snap-off of the water meniscus the distance between the tip of the                    i d th t f dtherefore show hydrophilic behavior [5] spec men an  e wa er sur ace was measure  Almost identical hair structures in S biloba Untreated and Teflon-coated Salvinia hairs were dipped in water     .  d S i l t         A f t f t d b t t t d d T fl t d h i [5]an  . aur cu a a  ac or o  wo was measure  e ween un rea e  an  e on-coa e  a rs  Low-temperature SEM of a    frozen leaf with applied    d l t f t l lrop e  o  a wa er-g ycero  msolution mm2 m2100 µm untreated Teflon coated-Summary:A novel method to Schematic of a determine water adhesion       of topographically hydrophobic pinningSalvinia molesta   t t d d h i ll repulsionleaf s ruc ure  an  c em ca y heterogeneous structures  has been established  Hydrophilic tips lead to a airairhydrophilic0 5 mm pinning of the air-water- ,     interface hence stabilizemeniscus ,   th i t i t f water waterbetween the e a r-wa er n er ace  water glycerol A novel effect was found Schematic of the air retention by -  d l t d th     l i i i t ti a submerged Salvinia leafrop e  an  e exp a n ng a r-re en on   terminal cells under water [5]: the Salvinia Effect  KIT U i it f th St t f B d Wü tt b d – n vers y o  e a e o a en- r em erg anNational Research Center of the Helmholtz Association     

Measuring the water adhesion on structures of biological air-retaining surfaces

https://publikationen.bibliothek.kit.edu/220080848/3815752

Measuring the water adhesion on structures of biological air-retaining surfaces

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