Reversible Temperature‐Sensitive Liquid–Solid Triboelectrification with Polycaprolactone Material for Wetting Monitoring and Temperature Sensing

Abstract

Controlling liquid–solid triboelectrification is highly demanded in a wide range of applications, from electrostatic prevention to energy collection and utilization. Except for traditional unidirectional and irreversible ways, smart approaches are required urgently. Here, a novel temperature response liquid–solid triboelectric nanogenerator (TENG) is reported on the basis of a polycaprolactone (PCL) covered fluorinated alumina for tunable triboelectrification. The PCL conformation is regulated by temperature to endow the substrate controllable surface component and interfacial wettability to manipulate the liquid–solid triboelectricity flexibly. As the temperature rises from 20 to 40 °C, the short circuit current and the open‐circuit voltage of the PCL‐based TENG are reduced by more than 40 times. When the temperature drops to 20 °C, the electrical output can return to its original level again. Moreover, after one month, the electrical signal is still reversible and stable. In addition to water, the electrical output of organic liquid, such as ethylene glycol, also responds well to temperature. This work initially provides a new strategy for achieving the customizable manipulation of liquid–solid triboelectrification by polymer surface reorganization, gives a new idea for in situ monitoring the interfacial wettability changes, and configures the reconstruction of amphiphilic polymer using triboelectricity.

A New Reversible Thermosensitive Liquid–Solid TENG Based on a P(NIPAM‐MMA) Copolymer for Triboelectricity Regulation and Temperature Monitoring

“…[ 16 ] For example, liquid vibration during the transportation of crude oil and organic solvents would cause the accumulation of triboelectric charges on the surface of the pipe and tank wall, resulting in tragedies. [ 17 ] Therefore, effectively controlling the amount of electricity generated by liquid–solid friction still faces great challenges.…”

“…Stimuli‐responsive polymers are the possible candidates of solid material to realize controllable liquid–solid triboelectrification. [ 17 ] As a biocompatible and temperature‐sensitive material, N ‐isopropylacrylamide (NIPAM) that with thermal phase transition behavior and smart tunable properties has been widely applied in drug delivery, microreactors, embolic agents, protein adsorption, catalysts, and 3D printing. [ 31 ] Poly( N ‐isopropylacrylamide) (PNIPAM) is water‐soluble at room temperature and has a lower critical solution temperature (LCST) of 32 °C.…”

“…[16] For example, liquid vibration during the transportation of crude oil and organic solvents would cause the accumulation of triboelectric charges on the surface of the pipe and tank wall, resulting in tragedies. [17] Therefore, effectively controlling the amount of electricity generated by liquid-solid friction still faces great challenges.An in-depth understanding of the influencing factors and the mechanism of the L-S TENG is the key to manipulating its electrification. [18] The existing electric double layer theory proves that electron transfer dominates the liquid-solid triboelectric process, accompanied by a small amount of ion transfer.…”

In Situ Nanofluid Dispersion Monitoring by Liquid–Solid Triboelectric Nanogenerator Based on Tuning the Structure of the Electric Double Layer

“…[22][23][24][25][26] These research were mostly focused on the solid-solid interfaces, while the NFD detection relied on the liquid-solid TENG (LS-TENG), which once proved having a comparable perception but has not been reported yet as a detection probe. [27,28] On one hand, the LS-TENG owns merits of wear resistance and durability, also can output more stable signal for the better flexibility and fluidity of liquids, and maintain higher sensitivity with its encapsulation isolated to the external ambients. [29,30] Moreover, the newly proposed Wang's hybrid layer model by Wang et al has elaborated the potential distribution and changing rules of the generated charges at liquid-solid contact interface, settling the quantization problem of the transferred charges in the parameters identification for the NFD analysis.…”

A β-cyclodextrin enhanced polyethylene terephthalate film with improved contact charging ability in a high humidity environment

“…Generally speaking, the factors that affect the electrical output of TENG include the dielectric and triboelectricity of the material 14,15 , the structure of the surface 16,17 , the thickness of the material 18,19 , the temperature 20 , humidity 21 and atmosphere 22,23 of the environment, and so on. In terms of environmental humidity, water molecules in the environment adhere to the surface of the friction layer, resulting in a decrease in the amount of triboelectricity between the polymers 24,25 ; at the same time, the migration of water molecules will carry the charges on the surface of the friction layer into the environment, resulting in polymer degradation, so the dissipation of surface charge increases 26,27 .…”