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Luo M, Liu Z, Wang Q, Liu R, Xu Y, Wang K, Shi X, Ye S. Surface Engineering on Polyimide-Silver Films in Low-Cost, Flexible Humidity Sensors. ACS APPLIED MATERIALS & INTERFACES 2022; 14:16621-16630. [PMID: 35360903 DOI: 10.1021/acsami.2c00503] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In this work, surface engineering is applied to polyimide (PI) films to fabricate low-cost Ag/PI wireless humidity sensors with a resonant frequency of 2.45 GHz. The sensors were obtained by in situ metallization technique coupled with inkjet printing, where PI plays triple roles as a flexible substrate, ion-exchange surface, and sensing material to moisture. Moreover, the humidity sensitivity can be enhanced by the improvement of hydrophilicity via loading with different ions on the PI surface, which has been demonstrated by Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), and contact angle measurements. The wireless humidity sensor loaded with K+ ions has the maximum sensitivity of 97.7 kHz/% RH at a low relative humidity range of 20-65% and 359.7 kHz/% RH at a high relative humidity of 65-90%, respectively. Accordingly, a sensing mechanism of the fabricated humidity sensor has been discussed in detail. On the other hand, the characteristics of the humidity sensor such as response and recovery speed and stability are analyzed. The mechanical performance tests show that the humidity sensor displays excellent flexibility and good mechanical stability. A strong adhesion between the Ag antenna and PI substrate can be found as well. The passive wireless humidity sensor described in this work has the advantages of having a simple structure, low cost, high sensitivity, long-term stability, and good mechanical properties, which has potential applications in automated industry and healthcare with real-time humidity monitoring.
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Affiliation(s)
- Mengxue Luo
- School of Printing and Packaging, Wuhan University, Wuhan 430072, Hubei Province, People's Republic of China
| | - Zhangming Liu
- School of Printing and Packaging, Wuhan University, Wuhan 430072, Hubei Province, People's Republic of China
| | - Qi Wang
- School of Printing and Packaging, Wuhan University, Wuhan 430072, Hubei Province, People's Republic of China
| | - Rui Liu
- School of Printing and Packaging, Wuhan University, Wuhan 430072, Hubei Province, People's Republic of China
| | - Yuan Xu
- School of Printing and Packaging, Wuhan University, Wuhan 430072, Hubei Province, People's Republic of China
| | - Ke Wang
- School of Printing and Packaging, Wuhan University, Wuhan 430072, Hubei Province, People's Republic of China
| | - Xinzhi Shi
- Electronic Information School, Wuhan University, Wuhan 430072, Hubei Province, People's Republic of China
| | - Shuangli Ye
- School of Printing and Packaging, Wuhan University, Wuhan 430072, Hubei Province, People's Republic of China
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Wang N, Tong J, Wang J, Wang Q, Chen S, Sheng B. Polyimide-Sputtered and Polymerized Films with Ultrahigh Moisture Sensitivity for Respiratory Monitoring and Contactless Sensing. ACS APPLIED MATERIALS & INTERFACES 2022; 14:11842-11853. [PMID: 35143181 DOI: 10.1021/acsami.1c24833] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Respiratory monitoring and contactless sensing using the moisture produced by respiration and perspiration have garnered considerable attention in recent years. In this study, we fabricated polyimide-sputtered and polymerized (PSP) humidity sensors with ultrahigh capacitive sensitivity, fast response, and a wide working range of relative humidity (RH). The sensors produced >40 000 times increment in the sensing signal over the 10-95% RH range at 10 Hz and exhibited good performance at low RH levels (<40%) as well. These sensors displayed excellent sensing properties with small hysteresis, long-time stability, and fast response and recovery times (2.4 and 1.2 s, respectively). In the mechanism study of PSP humidity sensors, we found that the high sensitivity can be attributed to massive hydrophilic functional groups formed on the polymer chains by moist aging with oxidation and the fast response speed is due to the mesoporous structure of PSP films. We also fabricated a 5 × 5 array of PSP humidity sensors to identify the shapes of wet objects and of leaves during transpiration. Thus, we reported a novel and effective method for fabricating high-performance humidity polymer films, channeling new pathways for the development of advanced humidity and gas sensors.
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Affiliation(s)
- Nan Wang
- School of Optical Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
- Shanghai Key Laboratory of Modern Optical Systems, Engineering Research Center of Optical Instruments and Systems, Shanghai 200093, China
| | - Jianhao Tong
- School of Optical Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
- Shanghai Key Laboratory of Modern Optical Systems, Engineering Research Center of Optical Instruments and Systems, Shanghai 200093, China
| | - Junjie Wang
- School of Optical Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
- Shanghai Key Laboratory of Modern Optical Systems, Engineering Research Center of Optical Instruments and Systems, Shanghai 200093, China
| | - Qi Wang
- School of Optical Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
- Shanghai Key Laboratory of Modern Optical Systems, Engineering Research Center of Optical Instruments and Systems, Shanghai 200093, China
| | - Shangbi Chen
- School of Optical Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
- Shanghai Key Laboratory of Modern Optical Systems, Engineering Research Center of Optical Instruments and Systems, Shanghai 200093, China
- Shanghai Aerospace Control Technology Institute, Shanghai 200233, China
- Shanghai Xin Yue Lian Hui Electronic Technology Co. LTD, Shanghai 200233, China
| | - Bin Sheng
- School of Optical Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
- Shanghai Key Laboratory of Modern Optical Systems, Engineering Research Center of Optical Instruments and Systems, Shanghai 200093, China
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The Unmanned Systems Research Laboratory (USRL): A New Facility for UAV-Based Atmospheric Observations. ATMOSPHERE 2021. [DOI: 10.3390/atmos12081042] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The Unmanned Systems Research Laboratory (USRL) of the Cyprus Institute is a new mobile exploratory platform of the EU Research Infrastructure Aerosol, Clouds and Trace Gases Research InfraStructure (ACTRIS). USRL offers exclusive Unmanned Aerial Vehicle (UAV)-sensor solutions that can be deployed anywhere in Europe and beyond, e.g., during intensive field campaigns through a transnational access scheme in compliance with the drone regulation set by the European Union Aviation Safety Agency (EASA) for the research, innovation, and training. UAV sensor systems play a growing role in the portfolio of Earth observation systems. They can provide cost-effective, spatial in-situ atmospheric observations which are complementary to stationary observation networks. They also have strong potential for calibrating and validating remote-sensing sensors and retrieval algorithms, mapping close-to-the-ground emission point sources and dispersion plumes, and evaluating the performance of atmospheric models. They can provide unique information relevant to the short- and long-range transport of gas and aerosol pollutants, radiative forcing, cloud properties, emission factors and a variety of atmospheric parameters. Since its establishment in 2015, USRL is participating in major international research projects dedicated to (1) the better understanding of aerosol-cloud interactions, (2) the profiling of aerosol optical properties in different atmospheric environments, (3) the vertical distribution of air pollutants in and above the planetary boundary layer, (4) the validation of Aeolus satellite dust products by utilizing novel UAV-balloon-sensor systems, and (5) the chemical characterization of ship and stack emissions. A comprehensive overview of the new UAV-sensor systems developed by USRL and their field deployments is presented here. This paper aims to illustrate the strong scientific potential of UAV-borne measurements in the atmospheric sciences and the need for their integration in Earth observation networks.
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Kim J, Cho JH, Lee HM, Hong SM. Capacitive Humidity Sensor Based on Carbon Black/Polyimide Composites. SENSORS 2021; 21:s21061974. [PMID: 33799769 PMCID: PMC8001880 DOI: 10.3390/s21061974] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 03/04/2021] [Accepted: 03/04/2021] [Indexed: 01/03/2023]
Abstract
A novel capacitive humidity sensor based on carbon black/polyimide composites is presented in this paper. The details of the fabrication, sensor characteristics, and effect of the carbon black additive are described. It was confirmed that the polyimide composite filled with a tiny amount of carbon black was suitable for a humidity sensing dielectric. The humidity sensors with three different dielectrics, which were pure polyimide, 0.01 wt% carbon black/polyimide, and 0.05 wt% carbon black/polyimide, were fabricated by a micro-electro-mechanical-system (MEMS) process. As the amount of the carbon black additive increased, the sensitivity of the humidity sensor increased. The humidity sensor with 0.05 wt% of carbon black had a much higher sensitivity of 15.21% (20–80% RH, 0.2535%/% RH) than that of the sensor with pure polyimide, which was 9.73% (0.1622%/% RH). The addition of carbon black also led to an enhancement in the hysteresis and response speed. The hysteresis of the humidity sensor decreased from 2.17 to 1.80% when increasing the amount of the carbon black additive. The response speed of the humidity sensor with 0.05 wt% of carbon black was measured to be ~10% faster than that of the sensor with pure polyimide. The long-term stability of the humidity sensors was demonstrated as well.
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Affiliation(s)
- Jihong Kim
- Department of Electrical Engineering, Yeungnam University, Gyeongsan 38541, Korea;
| | - Jang-Hoon Cho
- Smart Sensor Research Center, Korea Electronics Technology Institute, Seongnam 13509, Korea; (J.-H.C.); (H.-M.L.)
| | - Hyung-Man Lee
- Smart Sensor Research Center, Korea Electronics Technology Institute, Seongnam 13509, Korea; (J.-H.C.); (H.-M.L.)
| | - Sung-Min Hong
- Smart Sensor Research Center, Korea Electronics Technology Institute, Seongnam 13509, Korea; (J.-H.C.); (H.-M.L.)
- Correspondence:
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Aman Qazi R, Saleem Khan M, Siddiq M, Ullah R, Ali Shah L, Ali M. Synthesis and characterization of functionalized MWCNTs/PMMA composites: device fabrication for RH sensing. POLYM-PLAST TECH MAT 2020. [DOI: 10.1080/25740881.2020.1759631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Raina Aman Qazi
- Polymer Laboratory, National Centre of Excellence in Physical Chemistry, University of Peshawar, Peshawar, Pakistan
| | - Mohammad Saleem Khan
- Polymer Laboratory, National Centre of Excellence in Physical Chemistry, University of Peshawar, Peshawar, Pakistan
| | - Muhammad Siddiq
- Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan
| | - Rizwan Ullah
- Polymer Laboratory, National Centre of Excellence in Physical Chemistry, University of Peshawar, Peshawar, Pakistan
| | - Luqman Ali Shah
- Polymer Laboratory, National Centre of Excellence in Physical Chemistry, University of Peshawar, Peshawar, Pakistan
| | - Muhammad Ali
- Materials Research Laboratory, Department of Physics, University of Peshawar, Peshawar, Pakistan
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Pan M, Sheng J, Liu J, Shi Z, Jiu L. Design and Verification of Humidity Sensors Based on Magnesium Oxide Micro-Arc Oxidation Film Layers. SENSORS (BASEL, SWITZERLAND) 2020; 20:s20061736. [PMID: 32244991 PMCID: PMC7146567 DOI: 10.3390/s20061736] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 03/15/2020] [Accepted: 03/16/2020] [Indexed: 06/11/2023]
Abstract
Humidity detection range is an important indicator for measuring the performance of humidity sensors, but semiconductor humidity sensors often face the problems of narrow detection ranges and insufficient detection sensitivities. In this paper, a magnesium oxide (MgO) humidity sensor based on micro-arc oxidation (MAO) technology was designed to solve these problems by simultaneously using impedance and capacitance as the response signals, as well as by normalizing the output of the two signals. The experimental results showed that the average output of the micro-arc MgO ceramic film, with impedance as the response signal, could reach 150 in the low relative humidity(RH) range (11.3-67% RH), which was much higher than its sensitivity in the high humidity range (< 1), and the film showed fast response (13 s) and recovery (61 s). Under high humidity conditions (67-97.3% RH), with capacitance as the response signal, the output of the micro-arc MgO was as high as 120. Therefore, the micro-arc MgO humidity sensor with impedance, and the sensor with capacitance as the response signal, demonstrated good stability in low humidity and in high humidity environments, respectively, indicating that the method of selecting appropriate response signals for different humidity environments can be applied to extend the humidity detection range of sensing material, and to improve the humidity detection capability of a sensor.
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Affiliation(s)
- Mingqiang Pan
- School of Mechanical and Electric Engineering, Soochow University, Suzhou 215123, China; (M.P.); (Z.S.); (L.J.)
- Jiangsu Provincial Key Labor Atory of Advanced Robotics, Soochow University, Suzhou 215123, China
- Robotics and Microsystems Center, Soochow University, Suzhou 215123, China
| | - Jun Sheng
- School of Mechanical and Electric Engineering, Soochow University, Suzhou 215123, China; (M.P.); (Z.S.); (L.J.)
- Jiangsu Provincial Key Labor Atory of Advanced Robotics, Soochow University, Suzhou 215123, China
- Robotics and Microsystems Center, Soochow University, Suzhou 215123, China
| | - Jizhu Liu
- School of Mechanical and Electric Engineering, Soochow University, Suzhou 215123, China; (M.P.); (Z.S.); (L.J.)
- Jiangsu Provincial Key Labor Atory of Advanced Robotics, Soochow University, Suzhou 215123, China
- Robotics and Microsystems Center, Soochow University, Suzhou 215123, China
| | - Zeming Shi
- School of Mechanical and Electric Engineering, Soochow University, Suzhou 215123, China; (M.P.); (Z.S.); (L.J.)
- Jiangsu Provincial Key Labor Atory of Advanced Robotics, Soochow University, Suzhou 215123, China
- Robotics and Microsystems Center, Soochow University, Suzhou 215123, China
| | - Lei Jiu
- School of Mechanical and Electric Engineering, Soochow University, Suzhou 215123, China; (M.P.); (Z.S.); (L.J.)
- Jiangsu Provincial Key Labor Atory of Advanced Robotics, Soochow University, Suzhou 215123, China
- Robotics and Microsystems Center, Soochow University, Suzhou 215123, China
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