Achieving a high sensitivity for practical applications has always been one of the main developmental directions for wearable flexible pressure sensors.This paper introduces a laser speckle grayscale lithography syste...Achieving a high sensitivity for practical applications has always been one of the main developmental directions for wearable flexible pressure sensors.This paper introduces a laser speckle grayscale lithography system and a novel method for fabricating random conical array microstructures using grainy laser speckle patterns.Its feasibility is attributed to the autocorrelation function of the laser speckle intensity,which adheres to a first-order Bessel function of the first kind.Through objective speckle size and exposure dose manipulations,we developed a microstructured photoresist with various micromorphologies.These microstructures were used to form polydimethylsiloxane microstructured electrodes that were used in flexible capacitive pressure sensors.These-1 sensors exhibited an ultra-high sensitivity:19.76 kPa for the low-pressure range of 0-100 Pa.Their minimum detection threshold was 1.9 Pa,and they maintained stability and resilience over 10,000 test cycles.These sensors proved to be adept at capturing physiological signals and providing tactile feedback,thereby emphasizing their practical value.展开更多
Liquid metal(LM)dielectric elastomers with high flexibility and excellent dielectric properties are ideal for flexible capacitive pressure sensors.However,the development of LM dielectric elastomers is hindered by the...Liquid metal(LM)dielectric elastomers with high flexibility and excellent dielectric properties are ideal for flexible capacitive pressure sensors.However,the development of LM dielectric elastomers is hindered by the challenge of unavoidable percolation at high LM fill ratios.Inhomogeneous distribution is an effective strategy to manipulate the percolation threshold.Herein,thermoplastic polyurethane(TPU)fiber mats featuring a unique rapeseed-shaped structure were designed for high LM content filling(up to 90 vol%)and prepared with the aid of an electrospinning technique,in which LM was locally concentrated in the TPU fibers of the composite mats to form isolated clusters,leading to an incredible improvement in the percolation threshold surpassing our calculated theoretical prediction(>90 vol%vs.83 vol%).The LM/TPU-Fiber mats are proven to be recyclable,temperature-insensitive,and waterproof,making them suitable for multiple usage environments.A flexible capacitive sensor prepared with LM/TPU-Fiber mats,capable of exceptional relative capacitance change(Max.ΔC/C_(0)=6.32),an impressive pressure range of 0-550 kPa with a sensitivity of 55 MPa^(−1),and high cyclic stability(>6000 cycles).With these outstanding attributes,the sensor holds great promise for applications in intelligent sorting,pressure distribution monitoring,and human-machine interaction.展开更多
基金supported by the Key Research and Development Program of Shanxi Province(202102030201002)the Changjiang Scholars and Innovative Research Team at the University of Ministry of Education of China(IRT_17R70)+2 种基金the State Key Program of National Natural Science of China(11434007)the 111 Project(D18001)the Fund for Shanxi“1331 Project”Key Subjects Construction.
文摘Achieving a high sensitivity for practical applications has always been one of the main developmental directions for wearable flexible pressure sensors.This paper introduces a laser speckle grayscale lithography system and a novel method for fabricating random conical array microstructures using grainy laser speckle patterns.Its feasibility is attributed to the autocorrelation function of the laser speckle intensity,which adheres to a first-order Bessel function of the first kind.Through objective speckle size and exposure dose manipulations,we developed a microstructured photoresist with various micromorphologies.These microstructures were used to form polydimethylsiloxane microstructured electrodes that were used in flexible capacitive pressure sensors.These-1 sensors exhibited an ultra-high sensitivity:19.76 kPa for the low-pressure range of 0-100 Pa.Their minimum detection threshold was 1.9 Pa,and they maintained stability and resilience over 10,000 test cycles.These sensors proved to be adept at capturing physiological signals and providing tactile feedback,thereby emphasizing their practical value.
基金supported by NSFC No.52473267 and No.52401249National Key Research and Development Program of China No.2021YFB3501504 and Zhejiang Provincial Key Research and Development Program(2024C01157)Zhejiang University Ningbo“Five in One”Campus Project(K-20213539).
文摘Liquid metal(LM)dielectric elastomers with high flexibility and excellent dielectric properties are ideal for flexible capacitive pressure sensors.However,the development of LM dielectric elastomers is hindered by the challenge of unavoidable percolation at high LM fill ratios.Inhomogeneous distribution is an effective strategy to manipulate the percolation threshold.Herein,thermoplastic polyurethane(TPU)fiber mats featuring a unique rapeseed-shaped structure were designed for high LM content filling(up to 90 vol%)and prepared with the aid of an electrospinning technique,in which LM was locally concentrated in the TPU fibers of the composite mats to form isolated clusters,leading to an incredible improvement in the percolation threshold surpassing our calculated theoretical prediction(>90 vol%vs.83 vol%).The LM/TPU-Fiber mats are proven to be recyclable,temperature-insensitive,and waterproof,making them suitable for multiple usage environments.A flexible capacitive sensor prepared with LM/TPU-Fiber mats,capable of exceptional relative capacitance change(Max.ΔC/C_(0)=6.32),an impressive pressure range of 0-550 kPa with a sensitivity of 55 MPa^(−1),and high cyclic stability(>6000 cycles).With these outstanding attributes,the sensor holds great promise for applications in intelligent sorting,pressure distribution monitoring,and human-machine interaction.
