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Photogated humidity-driven motility.

Zhang L, Liang H, Jacob J, Naumov P - Nat Commun (2015)

Bottom Line: Here we demonstrate that mechanical bistability caused by rapid and anisotropic adsorption and desorption of water vapour by a flexible dynamic element that harnesses the chemical potential across very small humidity gradients for perpetual motion can be effectively modulated with light.A mechanically robust material capable of rapid exchange of water with the surroundings is prepared that undergoes swift locomotion in effect to periodic shape reconfiguration with turnover frequency of <150 min(-1).The element can lift objects ∼85 times heavier and can transport cargos ∼20 times heavier than itself.

View Article: PubMed Central - PubMed

Affiliation: New York University Abu Dhabi, PO Box 129188, Abu Dhabi, United Arab Emirates.

ABSTRACT
Hygroinduced motion is a fundamental process of energy conversion that is essential for applications that require contactless actuation in response to the day-night rhythm of atmospheric humidity. Here we demonstrate that mechanical bistability caused by rapid and anisotropic adsorption and desorption of water vapour by a flexible dynamic element that harnesses the chemical potential across very small humidity gradients for perpetual motion can be effectively modulated with light. A mechanically robust material capable of rapid exchange of water with the surroundings is prepared that undergoes swift locomotion in effect to periodic shape reconfiguration with turnover frequency of <150 min(-1). The element can lift objects ∼85 times heavier and can transport cargos ∼20 times heavier than itself. Having an azobenzene-containing conjugate as a photoactive dopant, this entirely humidity-driven self-actuation can be controlled remotely with ultraviolet light, thus setting a platform for next-generation smart biomimetic hybrids.

No MeSH data available.


Related in: MedlinePlus

Voltage divider controlled by humidity- and light-driven PCAD@AG actuator.(a) Schematic of the voltage divider circuit. (b) A sketch showing the principles of operation of the bending sensor. When humidity or light is applied on PCAD@AG film, it bends to trigger bending of the sensor, whereupon the resistance changes affect the distribution of the voltage in the circuit. (c) Without applying a bending moment, the sensor used in the circuit is originally straight, but can be bent to change the resistance. (d,e) When the PCAD@AG actuator is driven by humidity, the output voltage oscillates with the bending of the sensor in the high-resistance regime (d) and in the low-resistance regime (e). (f,g) As the actuator is irradiated with light, the output voltage regularly alter with the sensor bending in the high- (f) and low- (g) resistance regime. The voltage output of the circuit in a is given by Vout=RbendV/(R+Rbend), where R=210 kΩ and V=3 V.
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f6: Voltage divider controlled by humidity- and light-driven PCAD@AG actuator.(a) Schematic of the voltage divider circuit. (b) A sketch showing the principles of operation of the bending sensor. When humidity or light is applied on PCAD@AG film, it bends to trigger bending of the sensor, whereupon the resistance changes affect the distribution of the voltage in the circuit. (c) Without applying a bending moment, the sensor used in the circuit is originally straight, but can be bent to change the resistance. (d,e) When the PCAD@AG actuator is driven by humidity, the output voltage oscillates with the bending of the sensor in the high-resistance regime (d) and in the low-resistance regime (e). (f,g) As the actuator is irradiated with light, the output voltage regularly alter with the sensor bending in the high- (f) and low- (g) resistance regime. The voltage output of the circuit in a is given by Vout=RbendV/(R+Rbend), where R=210 kΩ and V=3 V.

Mentions: As a proof-of-concept application to energy conversion by the hybrid film, a voltage divider was designed and attached to a humidity/light-responsive sensor composed of the PCAD@AG composite as active component coupled to a flex sensor (Rbend in Fig. 6a). Bending of the PCAD@AG film by exposure to humidity or ultraviolet light induces bending of the sensor (Fig. 6b). The change of resistance of the sensor affects the after-voltage of the electrical circuit. By humidity-induced regular and reversible motion of the actuator, the voltage spectrum of the bending sensor could be varied in a wide sensing range (176–215 kΩ) when operating in the high-resistance regime and narrower sensing range (145–167 kΩ) in the low-resistance regime. Within the 176–215 kΩ range the output voltage was 1.63–1.48 V (Fig. 6d), while within the range 145–167 kΩ the output voltage was 1.77–1.67 V (Fig. 6e). When light was used to drive the actuator, the bending sensor showed similar efficiency to that observed with humidity-driven processes with wider sensing range (172–186 kΩ) on the high-resistance side that corresponds to output voltage range of 1.65–1.48 V (Fig. 6f). When bending on the low-resistance side (154–167 kΩ), the output voltage was 1.73–1.67 V (Fig. 6g). The output voltage was recorded in 1 s intervals. Apparently, humidity-driven bending of PCAD@AG film was able to direct the voltage divider within wider range relative to light-induced process. This design allows for a remote adjustment of the output voltage of the circuit simply by changes in environmental humidity or by exposure to ultraviolet light, which could have potentials for remote control of electrical circuits in hazardous environments. In a more advanced setup, the sensing unit coated with the humidity-active material that is exposed to humidity would normally be physically separated from the electronics so the water would not affect the long-term operation of the device.


Photogated humidity-driven motility.

Zhang L, Liang H, Jacob J, Naumov P - Nat Commun (2015)

Voltage divider controlled by humidity- and light-driven PCAD@AG actuator.(a) Schematic of the voltage divider circuit. (b) A sketch showing the principles of operation of the bending sensor. When humidity or light is applied on PCAD@AG film, it bends to trigger bending of the sensor, whereupon the resistance changes affect the distribution of the voltage in the circuit. (c) Without applying a bending moment, the sensor used in the circuit is originally straight, but can be bent to change the resistance. (d,e) When the PCAD@AG actuator is driven by humidity, the output voltage oscillates with the bending of the sensor in the high-resistance regime (d) and in the low-resistance regime (e). (f,g) As the actuator is irradiated with light, the output voltage regularly alter with the sensor bending in the high- (f) and low- (g) resistance regime. The voltage output of the circuit in a is given by Vout=RbendV/(R+Rbend), where R=210 kΩ and V=3 V.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4490392&req=5

f6: Voltage divider controlled by humidity- and light-driven PCAD@AG actuator.(a) Schematic of the voltage divider circuit. (b) A sketch showing the principles of operation of the bending sensor. When humidity or light is applied on PCAD@AG film, it bends to trigger bending of the sensor, whereupon the resistance changes affect the distribution of the voltage in the circuit. (c) Without applying a bending moment, the sensor used in the circuit is originally straight, but can be bent to change the resistance. (d,e) When the PCAD@AG actuator is driven by humidity, the output voltage oscillates with the bending of the sensor in the high-resistance regime (d) and in the low-resistance regime (e). (f,g) As the actuator is irradiated with light, the output voltage regularly alter with the sensor bending in the high- (f) and low- (g) resistance regime. The voltage output of the circuit in a is given by Vout=RbendV/(R+Rbend), where R=210 kΩ and V=3 V.
Mentions: As a proof-of-concept application to energy conversion by the hybrid film, a voltage divider was designed and attached to a humidity/light-responsive sensor composed of the PCAD@AG composite as active component coupled to a flex sensor (Rbend in Fig. 6a). Bending of the PCAD@AG film by exposure to humidity or ultraviolet light induces bending of the sensor (Fig. 6b). The change of resistance of the sensor affects the after-voltage of the electrical circuit. By humidity-induced regular and reversible motion of the actuator, the voltage spectrum of the bending sensor could be varied in a wide sensing range (176–215 kΩ) when operating in the high-resistance regime and narrower sensing range (145–167 kΩ) in the low-resistance regime. Within the 176–215 kΩ range the output voltage was 1.63–1.48 V (Fig. 6d), while within the range 145–167 kΩ the output voltage was 1.77–1.67 V (Fig. 6e). When light was used to drive the actuator, the bending sensor showed similar efficiency to that observed with humidity-driven processes with wider sensing range (172–186 kΩ) on the high-resistance side that corresponds to output voltage range of 1.65–1.48 V (Fig. 6f). When bending on the low-resistance side (154–167 kΩ), the output voltage was 1.73–1.67 V (Fig. 6g). The output voltage was recorded in 1 s intervals. Apparently, humidity-driven bending of PCAD@AG film was able to direct the voltage divider within wider range relative to light-induced process. This design allows for a remote adjustment of the output voltage of the circuit simply by changes in environmental humidity or by exposure to ultraviolet light, which could have potentials for remote control of electrical circuits in hazardous environments. In a more advanced setup, the sensing unit coated with the humidity-active material that is exposed to humidity would normally be physically separated from the electronics so the water would not affect the long-term operation of the device.

Bottom Line: Here we demonstrate that mechanical bistability caused by rapid and anisotropic adsorption and desorption of water vapour by a flexible dynamic element that harnesses the chemical potential across very small humidity gradients for perpetual motion can be effectively modulated with light.A mechanically robust material capable of rapid exchange of water with the surroundings is prepared that undergoes swift locomotion in effect to periodic shape reconfiguration with turnover frequency of <150 min(-1).The element can lift objects ∼85 times heavier and can transport cargos ∼20 times heavier than itself.

View Article: PubMed Central - PubMed

Affiliation: New York University Abu Dhabi, PO Box 129188, Abu Dhabi, United Arab Emirates.

ABSTRACT
Hygroinduced motion is a fundamental process of energy conversion that is essential for applications that require contactless actuation in response to the day-night rhythm of atmospheric humidity. Here we demonstrate that mechanical bistability caused by rapid and anisotropic adsorption and desorption of water vapour by a flexible dynamic element that harnesses the chemical potential across very small humidity gradients for perpetual motion can be effectively modulated with light. A mechanically robust material capable of rapid exchange of water with the surroundings is prepared that undergoes swift locomotion in effect to periodic shape reconfiguration with turnover frequency of <150 min(-1). The element can lift objects ∼85 times heavier and can transport cargos ∼20 times heavier than itself. Having an azobenzene-containing conjugate as a photoactive dopant, this entirely humidity-driven self-actuation can be controlled remotely with ultraviolet light, thus setting a platform for next-generation smart biomimetic hybrids.

No MeSH data available.


Related in: MedlinePlus