Tunable flexible capacitive pressure sensors using arrangement of polydimethylsiloxane micro-pyramids for bio-signal monitoring

Thouti, Eshwar; Nagaraju, A.; Chandran, Achu; Prakash, P.V.B.S.S; Shivanarayanamurthy, P.; Lal, Banwari; Kumar, Prem; Kothari, Prateek; Panwar, Deepak

doi:10.1016/j.sna.2020.112251

Cited by 59 publications

(25 citation statements)

References 42 publications

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“…23 Another study of a micropyramid capacitive sensor also showed two linear regions from the application of different pressures. 33 Next, a compression test on the p-MPB sensor was performed by contacting phantom tissue blocks of different moduli with a controlled displacement of 0.5 mm at a speed of 2.9 mm/s. The elastic modulus of each phantom block was measured by a tensile experiment.…”

Section: P-mp Fabrication and Signal Measurementmentioning

confidence: 99%

Balloon Catheter-Integrated Piezoelectric Micropyramid Arrays for Measuring Vascular Stiffness

Kang

Lee

Park

et al. 2023

ACS Appl. Mater. Interfaces

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Atherosclerosis is one of the severe cardiovascular diseases in which blood vessels lose elasticity and the lumen narrows. If atherosclerosis worsens, it commonly leads to acute coronary syndrome (ACS) due to the rupture of vulnerable plaque or aortic aneurysm. As the mechanical properties of vascular tissues vary from their conditions, measuring the vascular stiffness of an inner blood vessel wall may be applied to the accurate diagnosis of atherosclerotic symptoms. Therefore, early mechanical detection of vascular stiffness is highly needed for immediate medical attention for ACS. Even with conventional examination methods such as intravascular ultrasonography and optical coherence tomography, several limitations still remain that make it difficult to directly determine the mechanical properties of the vascular tissue. As piezoelectric materials convert mechanical energy to electricity without an external power source, a piezoelectric nanocomposite could be utilized as a balloon catheter-integrated mechanical sensor on its surface. Here, we present piezoelectric nanocomposite micropyramid balloon catheter (p-MPB) arrays for measuring vascular stiffness. We study the structural characterization and feasibility of p-MPB as endovascular sensors by conducting finite element method analyses. Also, multifaceted piezoelectric voltages are measured by compression/release tests, in vitro vascular phantom tests, and ex vivo porcine heart tests to confirm that the p-MPB sensor properly operates in blood vessels.

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Section: P-mp Fabrication and Signal Measurementmentioning

confidence: 99%

Balloon Catheter-Integrated Piezoelectric Micropyramid Arrays for Measuring Vascular Stiffness

Kang

Lee

Park

et al. 2023

ACS Appl. Mater. Interfaces

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“…Percussion wave (P wave), tidal wave (T wave), and diastolic wave (D wave) represent systolic and diastolic blood pressure, ventricular pressure and heart rate, which is consistent with the results detected in other pressure sensor related work. [60,61] After comparison, the waveform after exercise shows diverse characteristics, including the enhanced P wave and the insignificant T wave, which may be attributed to changes in the heart. The pulse information and waveform results obtained by the above sensors are consistent with the current pulse interpretation, indicating that the tactile sensor in this work can realize the detection of weak pulse signals.…”

Section: Application Of the Sensormentioning

confidence: 99%

Highly Reliable Sensitive Capacitive Tactile Sensor with Spontaneous Micron‐Pyramid Structures for Electronic Skins

Zhao

et al. 2022

Macro Materials & Eng

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In recent years, it is still challenging to develop a capacitive tactile sensor with low cost, high sensitivity, and controllable morphology. Herein, the flexible capacitive pressure sensor (FCPS) with high sensitivity is fabricated via a one-step template method to produce spontaneous micron-pyramid structured polydimethylsiloxane (PDMS) by releasing a four-way stretched PDMS film treated with ultraviolet ozone exposure. The capacitive sensor is composed of two silver nanowire electrodes coated on polyimide substrate and a patterned PDMS dielectric layer sandwiching in the middle, exhibits an ultrahigh sensitivity of 15.66 kPa −1 , an ultralow limit of detection of 0.2 Pa, a fast response time of 42.4 ms, and excellent cycling stability. The finite-elemental analysis suggests that the uniform micro-pyramid structures are vital to obtain ultrahigh sensitivity, low detection limit, and fast response. In particular, the FCPS can keep the tactile performance unchanged after 4000 repeated tests, reflecting the high robustness. In conclusion, the significant advantages of the sensor enable it to be well applied in the fields of sign language detection, spatial pressure distribution, and physiological signal monitoring, indicating that FCPS has a potential application prospect in the fields of flexible wearable electronic devices and electronic skins.

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“…However, piezocapacitive sensors often face the problem of low sensitivity. Therefore, many studies have introduced microstructures such as pyramids, , sandpaper-like structures, , semi-spherical arrays, , and microridge arrays , into the flexible piezocapacitive sensors to effectively improve the sensitivity of the sensors. For example, Zou et al reported a highly sensitive flexible pressure sensor based on an ionic dielectric layer with a hierarchical ridge microstructure, which has a high sensitivity of 145.45 kPa –1 in the range of 0–400 Pa .…”

Section: Introductionmentioning

confidence: 99%

One-Step Laser Direct-Printing Process of a Hybrid Microstructure for Highly Sensitive Flexible Piezocapacitive Sensors

Chen

Guo

Xiao

et al. 2023

ACS Appl. Mater. Interfaces

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Microstructures can effectively improve the sensing performance of flexible piezocapacitive sensors. Simple, low-cost fabrication methods for microstructures are key to facilitating the practical application of piezocapacitive sensors. Herein, based on the laser thermal effect and the thermal decomposition of glucose, a rapid, simple, and low-cost laser direct-printing process is proposed for the preparation of a polydimethylsiloxane (PDMS)-based electrode with a hybrid microstructure. Combining the PDMS-based electrode with an ionic gel film, highly sensitive piezocapacitive sensors with different hybrid microstructures are realized. Due to the good mechanical properties brought about by the hybrid microstructure and the double electric layer induced by the ionic gel film, the sensor with a porous X-type microstructure exhibits an ultrahigh sensitivity of 92.87 kPa–1 in the pressure range of 0–1000 Pa, a wide measurement range of 100 kPa, excellent stability (>3000 cycles), fast response time (100 ms) and recovery time (101 ms), and good reversibility. Furthermore, the sensor is used to monitor human physiological signals such as throat vibration, pulse, and facial muscle movement, demonstrating the application potential of the sensor in human health monitoring. Most importantly, the laser direct-printing process provides a new strategy for the one-step preparation of hybrid microstructures on thermal curing polymers.

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Tunable flexible capacitive pressure sensors using arrangement of polydimethylsiloxane micro-pyramids for bio-signal monitoring

Cited by 59 publications

References 42 publications

Balloon Catheter-Integrated Piezoelectric Micropyramid Arrays for Measuring Vascular Stiffness

Balloon Catheter-Integrated Piezoelectric Micropyramid Arrays for Measuring Vascular Stiffness

Highly Reliable Sensitive Capacitive Tactile Sensor with Spontaneous Micron‐Pyramid Structures for Electronic Skins

One-Step Laser Direct-Printing Process of a Hybrid Microstructure for Highly Sensitive Flexible Piezocapacitive Sensors

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