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Bioinspired tilt-angle fabricated structure gradient fibers: micro-drops fast transport in a long-distance.

Chen Y, Wang L, Xue Y, Jiang L, Zheng Y - Sci Rep (2013)

Bottom Line: Issues of surfaces, e.g., inspired from beetle's back, spider silk, cactus stem, etc., become the active area of research on designing novel materials in need of human beings to acquire fresh water resource from air.Here, we report the ability of micro-drop transport in a long distance on a bioinspired Fibers with Gradient Spindle-knots (BFGS), which are fabricated by tilt angle dip-coating method.The micro-drop of ~0.25 μL transports in distance of ~5.00 mm, with velocity of 0.10-0.22 m s⁻¹ on BFGS.

View Article: PubMed Central - PubMed

Affiliation: 1] Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University, Beijing, 100191 (P. R. China) [2].

ABSTRACT
Issues of surfaces, e.g., inspired from beetle's back, spider silk, cactus stem, etc., become the active area of research on designing novel materials in need of human beings to acquire fresh water resource from air. However, the design of materials on surface structure is little achieved on controlling of micro-scale drop transport in a long distance. Here, we report the ability of micro-drop transport in a long distance on a bioinspired Fibers with Gradient Spindle-knots (BFGS), which are fabricated by tilt angle dip-coating method. The micro-drop of ~0.25 μL transports in distance of ~5.00 mm, with velocity of 0.10-0.22 m s⁻¹ on BFGS. It is attributed to the multi-level cooperation of the release energy of drop coalescence along the gradient spindle-knots, in addition to capillary adhesion force and continuous difference of Laplace pressure, accordingly, water drops are driven to move fast directionally in a long distance on BFGS.

No MeSH data available.


Related in: MedlinePlus

Water drops directional movement for a long distance on BFGS.(a), The gradient spindle-knots are from smaller to bigger. Water condensed drops (1,2,3,5,6) form on the spindle-knots (at ~84 s) and they coalesce into bigger drops (4, 8, 7), respectively, and they move fast towards the biggest spindle-knots with ~5.0 mm, to coalesce into a biggest drop 9 on the bigger spindle-knot at ~130 s. (b), The details of the water drops in directional movement. Some situations of dynamic coalescence and movement show the drops (1 + 2 + 3 → 4) at ~84.40–84.50 s; drops (4 + 8) at ~128.36 s; drops (4 + 8 + 7 → 9) at ~128.44 s, respectively. Scale bars, 500 μm.
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f2: Water drops directional movement for a long distance on BFGS.(a), The gradient spindle-knots are from smaller to bigger. Water condensed drops (1,2,3,5,6) form on the spindle-knots (at ~84 s) and they coalesce into bigger drops (4, 8, 7), respectively, and they move fast towards the biggest spindle-knots with ~5.0 mm, to coalesce into a biggest drop 9 on the bigger spindle-knot at ~130 s. (b), The details of the water drops in directional movement. Some situations of dynamic coalescence and movement show the drops (1 + 2 + 3 → 4) at ~84.40–84.50 s; drops (4 + 8) at ~128.36 s; drops (4 + 8 + 7 → 9) at ~128.44 s, respectively. Scale bars, 500 μm.

Mentions: What is interesting is that BFGS we prepared display a property to transport water drops in a long distance. In our previous studies21415193031, we reproduced the structural features similar to that of wetted spider silks. Specifically, the tiny water droplets directional driving on spindle-knots and a big drop pinning between two spindle-knots (uniform spindle-knots) were investigated significantly. However, directional movements of tiny water drops are usually limited in a short distance on surfaces of most previous as-designed fibers. Here, the water directional movement of the gradient spindle-knots can be carried out under a humidity of more than 90% via fog flow at rate of ~30 cm s−1, which is observed by CCD camera. As shown in Figure 2, there are four spindle-knots from smaller to bigger one on fiber (the left top), with the width ranged from ~180 to ~400 μm and height from ~75 to ~120 μm. The pitches are not more than ~1.5 mm in length. The whole process is in the time of ~130 s. In details, at ~84.0 s, water drops (1, 2, 3) are condensed on the spindle-knots. In the time of ~125.0 s, the water drops grow and meantime the drops coalesce and move towards to bigger spindle-knots direction. Subsequently, drops 1, 2 and 3 coalesce into drop 4, which are moving to the right about 2 mm at ~120 s. And drop 5 and 6 coalesce into drop 7. In the time of ~130 s, drop 4, 7 and 8 coalesce into drop 9. All whole process, the water is directionally moving across four spindle-knots in distance of ~5.0 mm. Figure 2b shows the details of water drop coalescence and movement in direction at ~84–128.44 s, where the drops (1 + 2 + 3) fast coalesce into drop 4 at ~84.40–84.50 s; drops (4 + 8) coalesce together at ~128.36 s; drops (4 + 8 + 7) coalesce directionally into drop 9 at ~128.44 s, respectively. The BFGS can be continuous to perform water drop transport and display the repeatability as shown in Fig. S3. In contrast, no obvious movements of water drops in a long distance appear on a uniform nylon fiber with PVDF coating and uniform spindle-knots fiber when they are horizontally placed under a humidity of more than 90% via fog flow at rate of ~30 cm s−1, where the water drops are coalesced with surrounding drops and stay on the original position (on the uniform nylon fiber, see Fig. S4a) or stably hang on two uniform spindle-knots (on the uniform spindle-knots fiber, see Fig. S4b). In our investigation, pitch of two spindle-knots influences the distance of water transport. If the pitches of two spindle-knots are more than 1.5 mm in length, droplets doesn't usually move to far-distance another larger spindle-knot, e.g., a pitch of ~1.8 mm, which water transport is not conducive to a long distance (see Fig. S5).


Bioinspired tilt-angle fabricated structure gradient fibers: micro-drops fast transport in a long-distance.

Chen Y, Wang L, Xue Y, Jiang L, Zheng Y - Sci Rep (2013)

Water drops directional movement for a long distance on BFGS.(a), The gradient spindle-knots are from smaller to bigger. Water condensed drops (1,2,3,5,6) form on the spindle-knots (at ~84 s) and they coalesce into bigger drops (4, 8, 7), respectively, and they move fast towards the biggest spindle-knots with ~5.0 mm, to coalesce into a biggest drop 9 on the bigger spindle-knot at ~130 s. (b), The details of the water drops in directional movement. Some situations of dynamic coalescence and movement show the drops (1 + 2 + 3 → 4) at ~84.40–84.50 s; drops (4 + 8) at ~128.36 s; drops (4 + 8 + 7 → 9) at ~128.44 s, respectively. Scale bars, 500 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3795351&req=5

f2: Water drops directional movement for a long distance on BFGS.(a), The gradient spindle-knots are from smaller to bigger. Water condensed drops (1,2,3,5,6) form on the spindle-knots (at ~84 s) and they coalesce into bigger drops (4, 8, 7), respectively, and they move fast towards the biggest spindle-knots with ~5.0 mm, to coalesce into a biggest drop 9 on the bigger spindle-knot at ~130 s. (b), The details of the water drops in directional movement. Some situations of dynamic coalescence and movement show the drops (1 + 2 + 3 → 4) at ~84.40–84.50 s; drops (4 + 8) at ~128.36 s; drops (4 + 8 + 7 → 9) at ~128.44 s, respectively. Scale bars, 500 μm.
Mentions: What is interesting is that BFGS we prepared display a property to transport water drops in a long distance. In our previous studies21415193031, we reproduced the structural features similar to that of wetted spider silks. Specifically, the tiny water droplets directional driving on spindle-knots and a big drop pinning between two spindle-knots (uniform spindle-knots) were investigated significantly. However, directional movements of tiny water drops are usually limited in a short distance on surfaces of most previous as-designed fibers. Here, the water directional movement of the gradient spindle-knots can be carried out under a humidity of more than 90% via fog flow at rate of ~30 cm s−1, which is observed by CCD camera. As shown in Figure 2, there are four spindle-knots from smaller to bigger one on fiber (the left top), with the width ranged from ~180 to ~400 μm and height from ~75 to ~120 μm. The pitches are not more than ~1.5 mm in length. The whole process is in the time of ~130 s. In details, at ~84.0 s, water drops (1, 2, 3) are condensed on the spindle-knots. In the time of ~125.0 s, the water drops grow and meantime the drops coalesce and move towards to bigger spindle-knots direction. Subsequently, drops 1, 2 and 3 coalesce into drop 4, which are moving to the right about 2 mm at ~120 s. And drop 5 and 6 coalesce into drop 7. In the time of ~130 s, drop 4, 7 and 8 coalesce into drop 9. All whole process, the water is directionally moving across four spindle-knots in distance of ~5.0 mm. Figure 2b shows the details of water drop coalescence and movement in direction at ~84–128.44 s, where the drops (1 + 2 + 3) fast coalesce into drop 4 at ~84.40–84.50 s; drops (4 + 8) coalesce together at ~128.36 s; drops (4 + 8 + 7) coalesce directionally into drop 9 at ~128.44 s, respectively. The BFGS can be continuous to perform water drop transport and display the repeatability as shown in Fig. S3. In contrast, no obvious movements of water drops in a long distance appear on a uniform nylon fiber with PVDF coating and uniform spindle-knots fiber when they are horizontally placed under a humidity of more than 90% via fog flow at rate of ~30 cm s−1, where the water drops are coalesced with surrounding drops and stay on the original position (on the uniform nylon fiber, see Fig. S4a) or stably hang on two uniform spindle-knots (on the uniform spindle-knots fiber, see Fig. S4b). In our investigation, pitch of two spindle-knots influences the distance of water transport. If the pitches of two spindle-knots are more than 1.5 mm in length, droplets doesn't usually move to far-distance another larger spindle-knot, e.g., a pitch of ~1.8 mm, which water transport is not conducive to a long distance (see Fig. S5).

Bottom Line: Issues of surfaces, e.g., inspired from beetle's back, spider silk, cactus stem, etc., become the active area of research on designing novel materials in need of human beings to acquire fresh water resource from air.Here, we report the ability of micro-drop transport in a long distance on a bioinspired Fibers with Gradient Spindle-knots (BFGS), which are fabricated by tilt angle dip-coating method.The micro-drop of ~0.25 μL transports in distance of ~5.00 mm, with velocity of 0.10-0.22 m s⁻¹ on BFGS.

View Article: PubMed Central - PubMed

Affiliation: 1] Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University, Beijing, 100191 (P. R. China) [2].

ABSTRACT
Issues of surfaces, e.g., inspired from beetle's back, spider silk, cactus stem, etc., become the active area of research on designing novel materials in need of human beings to acquire fresh water resource from air. However, the design of materials on surface structure is little achieved on controlling of micro-scale drop transport in a long distance. Here, we report the ability of micro-drop transport in a long distance on a bioinspired Fibers with Gradient Spindle-knots (BFGS), which are fabricated by tilt angle dip-coating method. The micro-drop of ~0.25 μL transports in distance of ~5.00 mm, with velocity of 0.10-0.22 m s⁻¹ on BFGS. It is attributed to the multi-level cooperation of the release energy of drop coalescence along the gradient spindle-knots, in addition to capillary adhesion force and continuous difference of Laplace pressure, accordingly, water drops are driven to move fast directionally in a long distance on BFGS.

No MeSH data available.


Related in: MedlinePlus