17 research outputs found
Quantifying Wetting Dynamics with Triboelectrification
Wetting is often perceived as an intrinsic surface property of materials, but
determining its evolution is complicated by its complex dependence on roughness
across the scales. The Wenzel state, where liquids have intimate contact with
the rough substrate, and the Cassie-Baxter state, where liquids sit onto air
pockets formed between asperities, are only two states among the plethora of
wetting behaviors. Furthermore, transitions from the Cassie-Baxter to the
Wenzel state dictate completely different surface performance, such as
anti-contamination, anti-icing, drag reduction etc.; however, little is known
about how transition occurs during time between the several wetting modes. In
this paper, we show that wetting dynamics can be accurately quantified and
tracked using solid-liquid triboelectrification. Theoretical underpinning
reveals how surface micro-/nano-geometries regulate stability/infiltration,
also demonstrating the generality of our theoretical approach in understanding
wetting transitions.Comment: Both Main and SI uploaded in a single fil
Innovative Technology for SelfâPowered Sensors: Triboelectric Nanogenerators
Abstract Internet of Things and wearable technology's quick development have opened up a vast market for sensor systems. However, typical sensors' external power supplies' short lifespan and expensive maintenance restrict them from being used more widely. Triboelectric nanogenerators (TENGs), a recently created mechanical energy harvesting and selfâpowered sensing device, show enormous promise to get over these restrictions. TENG can be used not only to power sensors instead of conventional chemical batteries but also be utilized to actualize sensing by taking advantage of the unique characteristics of the friction layer itself. Triboelectric nanogenerators efficiently provide crucial infrastructure for a new generation of sensing devices that gather data using several selfâpowered sensors in abundance. The recent progress in the development of TENGs applied in the sensor field is reviewed. First, the working mechanisms of solidâsolid TENG and solidâliquid TENG are introduced. Subsequently, the development of TENGâbased sensing systems and their application progress in selfâpowered temperature sensors, selfâpowered pressure sensors, selfâpowered humidity sensors, selfâpowered atmosphere sensors, selfâpowered wireless sensors, interface wetting status monitoring, solution property monitoring, and friction condition monitoring are highlighted. Finally, current challenges and open opportunities are discussed
Concealed Wireless Warning Sensor Based on Triboelectrification and Human-Plant Interactive Induction
With the continuous development of artificial intelligence, the demand for sensors with simple preparation and strong concealment continues to increase. However, most of the high-sensitivity sensors have complex manufacturing methods, high costs, and single functions. In this paper, a sensitive motion sensor based on the triboelectric interaction between a living plant and the human body was designed to detect the real-time movements of human beings and provide danger warning. A certain relationship exists between the triboelectric signal and the distance between the plant and the human body, with effective signals being detected in the range of 1.8âm. In addition, the triboelectric signal generated by each person is unique like a fingerprint, which can be used for biometrics. On the basis of the triboelectric signal, a wireless character entry warning system is designed. This sensor can not only send out a wireless warning signal at a specific distance but also allow one to receive the warning information synchronously on a mobile phone in real time. The wireless movement sensor receives signals through a living plant, and it has the characteristics of convenient use, strong concealment, and shielding difficulty. This sensor has the potential to be widely used in person recognition, danger warning, and motion monitoring
A new synergetic system based on triboelectric nanogenerator and corrosion inhibitor for enhanced anticorrosion performance
A new synergetic anticorrosion system was constructed via combining a self-powered cathodic protection based on triboelectric nanogenerator (TENG) and a green corrosion inhibitor of zinc gluconate (ZnG). Wind-driven TENG with a sandwich-like structure was designed, exhibiting high output performance with the peak values of short circuit current, output voltage and corresponding power reaching about 155 mu A, 402 V and 13.5 mW, respectively, under a wind speed of 10 m/s. With the assistance of TENG, the migration of corrosion inhibitor can be accelerated and the formation of the protective layer becomes faster due to the driving force of electric field. The shielding effect of protective layer in turn improves the cathodic protection of TENG. The immersion experiment and electrochemical measurements including Tafel polarization curves and EIS were taken to evaluate the performance of synergetic anticorrosion system. FESEM and EDS measurements were performed to analyze the morphology and composition of the protective layer and confirm the mechanism of synergetic anticorrosion. This work expands the application of TENG in the anticorrosion field and proposes a new thought of synergetic anticorrosion method
Soft/Hard-Coupled Amphiphilic Polymer Nanospheres for Water Lubrication
Amphiphilic polymer
nanospheres of polyÂ(3-sulfopropyl methacrylate potassium salt-<i>co</i>-styrene) [PÂ(SPMA-<i>co</i>-St)] were prepared
by a simple soap-free emulsion polymerization method and used as efficient
water lubrication additives to enhance the antiwear behaviors of the
Ti<sub>6</sub>Al<sub>4</sub>V alloy. The monodisperse and flexible
PÂ(SPMA-<i>co</i>-St) bicomponent copolymer nanospheres were
synthesized with a controllable manner by adjusting the mass fraction
ratio of the monomers, with the hydrophobic polystyrene (PSt) as the
hard skeletal carrier component and the hydrophilic PSPMA with a hydration
layer structure as the soft lubrication layer in the course of friction.
The influences of the monomer concentration, the copolymer nanosphere
additive content, the load, and the frequency of the friction conditions
on their tribological properties were studied in detail, and a probable
antiwear mechanism of the soft/hard-coupled copolymer nanospheres
under water lubrication was also proposed. The results show that compared
with pure PSt, the PÂ(SPMA-<i>co</i>-St) polymer nanospheres
exhibited better antiwear property as an additive for water lubrication,
and the friction coefficient and the wear volume first decreased and
then increased with the increase of the SPMA content, indicating that
the hydrophilic SPMA has a significant effect on lubrication properties
owing to its hydration performance. Furthermore, with the increase
of polymer nanosphere concentration, the friction coefficient and
wear amount also decreased to a stable and low value at a saturation
concentration of 1 wt %. The flexible polymer nanospheres with a hydrophilic
soft SPMA shell and a rigid PSt core exhibited good friction-reduction
and antiwear performance as lubrication additives, indicating their
promising and potential applications in water lubrication and biological
lubrication
Visualization of Charge Dynamics when Water Droplets Bounce on a Hydrophobic Surface
Visualizing the motion of water droplets
and understanding their
electrification behavior holds significance for applications related
to droplet transport, self-cleaning, and anti-icing/deicing and for
providing a comprehensive explanation of the solidâliquid triboelectrification
mechanism. Here, by constructing microcolumnar structures on the polytetrafluoroethylene
surface, a water droplet-based single electrode triboelectric nanogenerator
was fabricated for visualizing charge dynamics when a water droplet
bounces on a hydrophobic surface. The motion state of the water droplet
is closely linked to its electrification behavior through the integration
of a high-speed camera and an ammeter. The electrification behavior
stemming from the bounce of the water droplet is dynamically captured
in real-time. The results show that the magnitude and polarity of
the electrical signal have strong dependence on the motion state
of the water droplet. For instance, when a water droplet approaches
or moves away from the substrate in a single direction, a unipolar
electrical signal is generated. However, when the water droplet reaches
its limit in the initial motion direction, it signifies a static equilibrium
state, resulting in the electrical signal being at zero. Furthermore,
we examine the impact of factors such as impact speed, drop contact
area, contact line spreading/retraction speed, and impact angle on
electrification. Finally, based on the close relationship between
polyÂ(ethylene oxide) (PEO) droplet bounce dynamics and electrical
signals, the bouncing details of PEO droplets with different concentrations
are tracked by electrical signals. This study digitally presents the
whole process of droplet bounce in situ and provides a means for monitoring
and tracking droplet movement
Visualization of Charge Dynamics when Water Droplets Bounce on a Hydrophobic Surface
Visualizing the motion of water droplets
and understanding their
electrification behavior holds significance for applications related
to droplet transport, self-cleaning, and anti-icing/deicing and for
providing a comprehensive explanation of the solidâliquid triboelectrification
mechanism. Here, by constructing microcolumnar structures on the polytetrafluoroethylene
surface, a water droplet-based single electrode triboelectric nanogenerator
was fabricated for visualizing charge dynamics when a water droplet
bounces on a hydrophobic surface. The motion state of the water droplet
is closely linked to its electrification behavior through the integration
of a high-speed camera and an ammeter. The electrification behavior
stemming from the bounce of the water droplet is dynamically captured
in real-time. The results show that the magnitude and polarity of
the electrical signal have strong dependence on the motion state
of the water droplet. For instance, when a water droplet approaches
or moves away from the substrate in a single direction, a unipolar
electrical signal is generated. However, when the water droplet reaches
its limit in the initial motion direction, it signifies a static equilibrium
state, resulting in the electrical signal being at zero. Furthermore,
we examine the impact of factors such as impact speed, drop contact
area, contact line spreading/retraction speed, and impact angle on
electrification. Finally, based on the close relationship between
polyÂ(ethylene oxide) (PEO) droplet bounce dynamics and electrical
signals, the bouncing details of PEO droplets with different concentrations
are tracked by electrical signals. This study digitally presents the
whole process of droplet bounce in situ and provides a means for monitoring
and tracking droplet movement
Contact-electro-catalytic CO<sub>2</sub> reduction from ambient air.
Traditional catalytic techniques often encounter obstacles in the search for sustainable solutions for converting CO2 into value-added products because of their high energy consumption and expensive catalysts. Here, we introduce a contact-electro-catalysis approach for CO2 reduction reaction, achieving a CO Faradaic efficiency of 96.24%. The contact-electro-catalysis is driven by a triboelectric nanogenerator consisting of electrospun polyvinylidene fluoride loaded with single Cu atoms-anchored polymeric carbon nitride (Cu-PCN) catalysts and quaternized cellulose nanofibers (CNF). Mechanistic investigation reveals that the single Cu atoms on Cu-PCN can effectively enrich electrons during contact electrification, facilitating electron transfer upon their contact with CO2 adsorbed on quaternized CNF. Furthermore, the strong adsorption of CO2 on quaternized CNF allows efficient CO2 capture at low concentrations, thus enabling the CO2 reduction reaction in the ambient air. Compared to the state-of-the-art air-based CO2 reduction technologies, contact-electro-catalysis achieves a superior CO yield of 33 ÎŒmol g-1 h-1. This technique provides a solution for reducing airborne CO2 emissions while advancing chemical sustainability strategy