C. Neinhuis, identified as Christoph Neinhuis in the Bonn team's 1998 nomination profile, investigated how plant surfaces repel water and shed contamination with W. Barthlott. Their work connected plant structure with biomimetics.^[ref]

The 1997 experiment compared smooth and rough water-repellent plant surfaces. After artificial contamination, the specimens were rinsed using a sprinkler or fog generator; rolling droplets removed particles from the water-repellent leaves. This supplied a functional test of the lotus effect, beyond simply imaging an unusual surface.^[ref]

An original quantitative comparison would count retained particles over equal sampled areas. Suppose two surfaces each begin with 1000 particles; after matched rinsing one retains 50 and the other 400. The respective removal fractions are

1 - 50/1000 = 95%

and

1 - 400/1000 = 60%

. These hypothetical counts illustrate a measurable cleaning outcome, not data from Neinhuis's paper.

The comparison needs controls for particle type, initial loading, water delivery and how the sampled area is selected. A surface can have a large static contact angle yet pin droplets through contact-angle hysteresis. Measuring water repellency, droplet motion and contamination removal separately therefore tests more of the proposed mechanism than a single photograph of a rounded droplet.

Figure 1.

Wilhelm Barthlott at left and Christoph Neinhuis at right, identified in the 1998 Deutscher Zukunftspreis nomination profile; photograph by Ansgar Pudenz

Work by Christoph Neinhuis

 0  0

Wilhelm Barthlott

 0  0

W. Barthlott, or Wilhelm Barthlott, investigated the structure and function of plant surfaces using scanning electron microscopy. His group connected microscopic surface features with water repellency and self-cleaning, giving the lotus effect an experimental basis and motivating technical surface designs.^[ref]

With C. Neinhuis, Barthlott compared plant surfaces after adding particles and applying controlled artificial rinsing. The measured function was particle removal by rolling droplets, interpreted together with surface microrelief and water repellency.^[ref] The later team interview describes how botanical observations motivated materials research rather than beginning from an already specified industrial design.^[ref]

An original force-balance illustration explains why easy rolling matters. Model a droplet of mass

m

on an inclined surface as having a fixed retention force

F_{r}

. Downhill motion can begin when

m g sin α > F_{r}

, where

α

is the tilt. For stipulated

m = 10 mg

g = 9.81 m s^{- 2}

and

F_{r} = 20 μ N

, the threshold is

α = arcsin (\frac{20 \times 1 0 ^{- 6}}{1 0 ^{- 5} \times 9.81}) \approx 11. 8^{\circ} .

(1)

This simplified threshold is not a measured value for a lotus leaf. It shows that droplet mass and retention both affect motion; a high static contact angle alone does not supply the needed force balance. Real retention also depends on surface defects, droplet geometry and wetting history.

Figure 1.

Wilhelm Barthlott, portrait linked from his individual Lotus-Salvinia research profile

Work by Wilhelm Barthlott

 0  0

Michael G. Mason

 0  0

Michael G. Mason is a plant researcher credited as first author of a 2014 study of sugar supply and apical dominance. The paper lists an affiliation with the School of Biological Sciences at the University of Queensland and credits Mason with research design, experiments, analysis and writing.

The team measured the timing of pea bud growth after removal of the shoot tip, alongside changes in stem auxin and sugar supply. Buds began to grow before the measured local decline in auxin; supplying sucrose also promoted release from inhibition. The result challenged a simple account in which depletion of apically supplied auxin must be the immediate trigger. Its strength is the combination of time-resolved observations and a direct resource manipulation, rather than correlation between branching and sugar abundance alone.^[ref]

 Discussion (0)  Subscribe (1) New discussion

 Discussion (0) New discussion