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Scaling up nanoscale water-driven energy conversion into evaporation-driven engines and generators.

Chen X, Goodnight D, Gao Z, Cavusoglu AH, Sabharwal N, DeLay M, Driks A, Sahin O - Nat Commun (2015)

Bottom Line: These engines start and run autonomously when placed at air-water interfaces.Using these engines, we demonstrate an electricity generator that rests on water while harvesting its evaporation to power a light source, and a miniature car (weighing 0.1 kg) that moves forward as the water in the car evaporates.Evaporation-driven engines may find applications in powering robotic systems, sensors, devices and machinery that function in the natural environment.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Columbia University, New York 10027, New York, USA.

ABSTRACT
Evaporation is a ubiquitous phenomenon in the natural environment and a dominant form of energy transfer in the Earth's climate. Engineered systems rarely, if ever, use evaporation as a source of energy, despite myriad examples of such adaptations in the biological world. Here, we report evaporation-driven engines that can power common tasks like locomotion and electricity generation. These engines start and run autonomously when placed at air-water interfaces. They generate rotary and piston-like linear motion using specially designed, biologically based artificial muscles responsive to moisture fluctuations. Using these engines, we demonstrate an electricity generator that rests on water while harvesting its evaporation to power a light source, and a miniature car (weighing 0.1 kg) that moves forward as the water in the car evaporates. Evaporation-driven engines may find applications in powering robotic systems, sensors, devices and machinery that function in the natural environment.

No MeSH data available.


Related in: MedlinePlus

Hygroscopy-driven artificial muscles.Photos of spore-coated polyimide tapes at high (a) and low (b) relative humidity. Patterning equally spaced spore layers on both sides of a plastic tape creates linearly expanding and contracting muscles (c,d). HYDRA strips can work in parallel to lift weights (e,f). (g) Elongation of individual strips as a function of relative humidity shows that HYDRAs can quadruple their length. The inset shows estimated radius of curvature of the arcs forming the HYDRAs. Markers indicate the average data values with error bars showing the s.d. calculated from five measurements. (h) The elongation of HYDRAs reduced only slightly after one million cycles. The inset shows the time trace of a muscle displacement before and after 1 million cycles. (i) The normalized length of a HYDRA strip in dry and humid conditions as a function of load weights. Scale bars, 2 mm (a,b); 2 cm (c–f) and 1 cm (g,i).
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f2: Hygroscopy-driven artificial muscles.Photos of spore-coated polyimide tapes at high (a) and low (b) relative humidity. Patterning equally spaced spore layers on both sides of a plastic tape creates linearly expanding and contracting muscles (c,d). HYDRA strips can work in parallel to lift weights (e,f). (g) Elongation of individual strips as a function of relative humidity shows that HYDRAs can quadruple their length. The inset shows estimated radius of curvature of the arcs forming the HYDRAs. Markers indicate the average data values with error bars showing the s.d. calculated from five measurements. (h) The elongation of HYDRAs reduced only slightly after one million cycles. The inset shows the time trace of a muscle displacement before and after 1 million cycles. (i) The normalized length of a HYDRA strip in dry and humid conditions as a function of load weights. Scale bars, 2 mm (a,b); 2 cm (c–f) and 1 cm (g,i).

Mentions: Figure 2a,b shows photos of an 8 μm-thick polyimide tape coated with an ∼3 μm-thick spore layer (using Bacillus subtilis spores missing most of their outer protein protective layers, due to mutations in cotE and gerE27) changing its curvature in humid and dry conditions. Using the design strategy outlined in Fig. 1c–f, we created longer tapes and assembled them in parallel (see Methods and Supplementary Fig. 1 for the details of sample preparation process). Figure 2c,d shows the resulting dramatic changes in the overall length of tapes in humid and dry conditions. When assembled in parallel, these tapes can lift weight against gravity in dry conditions (Fig. 2e,f and Supplementary Movie 3). Due to their hygroscopy-driven response, we refer to these actuators as hygroscopy-driven artificial muscles, or HYDRAs.


Scaling up nanoscale water-driven energy conversion into evaporation-driven engines and generators.

Chen X, Goodnight D, Gao Z, Cavusoglu AH, Sabharwal N, DeLay M, Driks A, Sahin O - Nat Commun (2015)

Hygroscopy-driven artificial muscles.Photos of spore-coated polyimide tapes at high (a) and low (b) relative humidity. Patterning equally spaced spore layers on both sides of a plastic tape creates linearly expanding and contracting muscles (c,d). HYDRA strips can work in parallel to lift weights (e,f). (g) Elongation of individual strips as a function of relative humidity shows that HYDRAs can quadruple their length. The inset shows estimated radius of curvature of the arcs forming the HYDRAs. Markers indicate the average data values with error bars showing the s.d. calculated from five measurements. (h) The elongation of HYDRAs reduced only slightly after one million cycles. The inset shows the time trace of a muscle displacement before and after 1 million cycles. (i) The normalized length of a HYDRA strip in dry and humid conditions as a function of load weights. Scale bars, 2 mm (a,b); 2 cm (c–f) and 1 cm (g,i).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4490384&req=5

f2: Hygroscopy-driven artificial muscles.Photos of spore-coated polyimide tapes at high (a) and low (b) relative humidity. Patterning equally spaced spore layers on both sides of a plastic tape creates linearly expanding and contracting muscles (c,d). HYDRA strips can work in parallel to lift weights (e,f). (g) Elongation of individual strips as a function of relative humidity shows that HYDRAs can quadruple their length. The inset shows estimated radius of curvature of the arcs forming the HYDRAs. Markers indicate the average data values with error bars showing the s.d. calculated from five measurements. (h) The elongation of HYDRAs reduced only slightly after one million cycles. The inset shows the time trace of a muscle displacement before and after 1 million cycles. (i) The normalized length of a HYDRA strip in dry and humid conditions as a function of load weights. Scale bars, 2 mm (a,b); 2 cm (c–f) and 1 cm (g,i).
Mentions: Figure 2a,b shows photos of an 8 μm-thick polyimide tape coated with an ∼3 μm-thick spore layer (using Bacillus subtilis spores missing most of their outer protein protective layers, due to mutations in cotE and gerE27) changing its curvature in humid and dry conditions. Using the design strategy outlined in Fig. 1c–f, we created longer tapes and assembled them in parallel (see Methods and Supplementary Fig. 1 for the details of sample preparation process). Figure 2c,d shows the resulting dramatic changes in the overall length of tapes in humid and dry conditions. When assembled in parallel, these tapes can lift weight against gravity in dry conditions (Fig. 2e,f and Supplementary Movie 3). Due to their hygroscopy-driven response, we refer to these actuators as hygroscopy-driven artificial muscles, or HYDRAs.

Bottom Line: These engines start and run autonomously when placed at air-water interfaces.Using these engines, we demonstrate an electricity generator that rests on water while harvesting its evaporation to power a light source, and a miniature car (weighing 0.1 kg) that moves forward as the water in the car evaporates.Evaporation-driven engines may find applications in powering robotic systems, sensors, devices and machinery that function in the natural environment.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Columbia University, New York 10027, New York, USA.

ABSTRACT
Evaporation is a ubiquitous phenomenon in the natural environment and a dominant form of energy transfer in the Earth's climate. Engineered systems rarely, if ever, use evaporation as a source of energy, despite myriad examples of such adaptations in the biological world. Here, we report evaporation-driven engines that can power common tasks like locomotion and electricity generation. These engines start and run autonomously when placed at air-water interfaces. They generate rotary and piston-like linear motion using specially designed, biologically based artificial muscles responsive to moisture fluctuations. Using these engines, we demonstrate an electricity generator that rests on water while harvesting its evaporation to power a light source, and a miniature car (weighing 0.1 kg) that moves forward as the water in the car evaporates. Evaporation-driven engines may find applications in powering robotic systems, sensors, devices and machinery that function in the natural environment.

No MeSH data available.


Related in: MedlinePlus