scholarly journals Flexible and active self-powered pressure, shear sensors based on freeze casting ceramic–polymer composites

2018 ◽  
Vol 11 (10) ◽  
pp. 2919-2927 ◽  
Author(s):  
Mengying Xie ◽  
Yan Zhang ◽  
Marcin J. Kraśny ◽  
Chris Bowen ◽  
Hamideh Khanbareh ◽  
...  

Self-powered flexible and highly active piezoelectric composite sensors that operate in various sensing modes are manufactured using freeze casting.

2019 ◽  
Author(s):  
Chris Bowen

We demonstrate self-powered flexible and highly active pressure and shear sensors based on ice-templated ceramic-polymer structures. A lamellar lead zirconate titanate (PZT) structure is initially developed via freeze-casting and the piezoelectric composites are formed by impregnating a polydimethylsiloxane (PDMS) matrix into the aligned pore channels. The structured PZT-PDMS composites exhibited a high effective longitudinal piezoelectric coefficient (d*33) of 750 pC/N, which is higher than that of the monolithic ceramic due to the combination of bending and flexural effects. The use of freeze casting enables the manufacture of complex and arbitrary shaped 3D piezoelectric architectures, along with the unique advantages of low-cost and ease of fabrication. A 14×14 mm2 PZT-PDMS pressure sensor was able to bend to a small radius of 8 mm and maintain a high d33. Furthermore, the manufactured self-powered sensors are demonstrated in a range of applications, such as, acceleration, strain and touch sensors that use the d33, d31 and d15 coefficients to detect longitudinal, transverse and shear loads. This work expands on the potential applications of freeze casting and provides new opportunities for the manufacture of future electronic sensors.


2016 ◽  
Vol 72 (6) ◽  
pp. 47-52
Author(s):  
T.-W. Chang ◽  
Y.-T. Rao ◽  
Z.-H. Lin

2020 ◽  
Vol 109 ◽  
pp. 101289
Author(s):  
Jie Yang ◽  
Wei Yang ◽  
Wei Chen ◽  
Xiaoming Tao

Research ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Maosen Yang ◽  
Jinmei Liu ◽  
Dong Liu ◽  
Jingyi Jiao ◽  
Nuanyang Cui ◽  
...  

As an important way of converting mechanical energy into electric energy, a piezoelectric nanogenerator (PENG) has been widely applied in energy harvesting as well as self-powered sensors in recent years. However, its robustness and durability are still severely challenged by frequent and inevitable mechanical impacts in real application environments. Herein, a fully self-healing PENG (FS-PENG) as a self-powered pressure sensing electronic skin is reported. The self-healing piezoelectric composite and self-healing Ag NW electrode fabricated through mixing piezoelectric PZT particles and conductive Ag NWs into self-healing polydimethylsiloxane (H-PDMS) are assembled into the sandwich structure FS-PENG. The FS-PENG could not only effectively convert external stimulation into electrical signals with a linear response to the pressure but also retain the excellent self-healing and stable sensing property after multiple cycles of cutting and self-healing process. Moreover, a self-healing pressure sensor array composed of 9 FS-PENGs was attached on the back of the human hand to mimic the human skin, and accurate monitoring of the spatial position distribution and magnitude of the pressure was successfully realized.


2019 ◽  
Author(s):  
Chris Bowen

Energy harvesting is an important developing technology for a new generation of self-powered sensornetworks. This paper demonstrates the significant improvement in the piezoelectric energy harvestingperformance of barium titanate by forming highly aligned porosity using freeze casting. Firstly, a finiteelement model demonstrating the effect of pore morphology and angle with respect to poling fieldon the poling behaviour of porous ferroelectrics was developed. A second model was then developedto understand the influence of microstructure-property relationships on the poling behaviour of porous freeze cast ferroelectric materials and their resultant piezoelectric and energy harvestingproperties. To compare with model predictions, porous barium titanate was fabricated using freeze casting to form highly aligned microstructures with excellent longitudinal piezoelectric straincoefficients, d33. The freeze cast barium titanate with 45 vol.% porosity had a d33 = 134.5 pC/N, which compared favourably to d33= 144.5 pC/N for dense barium titanate. The d33 coefficients of the freezecast materials were also higher than materials with uniformly distributed spherical porosity due toimproved poling of the aligned microstructures, as predicted by the models. Both model andexperimental data indicated that introducing porosity provides a large reduction in the permittivity of barium titanate, which leads to a substantial increase in energy harvesting figure of merit, with a maximum of 3.79 pm2/N for barium titanate with 45 vol.% porosity, compared to only 1.40 pm2/N for dense barium titanate. Dense and porous barium titanate materials were then used to harvest energy from a mechanical excitation by rectification and storage of the piezoelectric charge on a capacitor. The porous barium titanate charged the capacitor to a voltage of 234 mV compared to 96 mV for the dense material, indicating a 2.4-fold increase that was similar to that predicted by the energy harvesting figures of merit.


2016 ◽  
Vol 237 ◽  
pp. 534-544 ◽  
Author(s):  
Nagamalleswara Rao Alluri ◽  
Sophia Selvarajan ◽  
Arunkumar Chandrasekhar ◽  
Saravanakumar Balasubramaniam ◽  
Ji Hyun Jeong ◽  
...  

Author(s):  
Alicja Urbaniak ◽  
Anna Skarpańska-Stejnborn

Abstract. The aim of the study was to review recent findings on the use of POM supplements in athletes of various disciplines and physically active participants. Eleven articles published between 2010 and 2018 were included, where the total number of investigated subjects was 176. Male participants constituted the majority of the group (n = 155), as compared to females (n = 21). 45% of research described was conducted on athletes, whereas the remaining studies were based on highly active participants. Randomised, crossover, double-blind study designs constituted the majority of the experimental designs used. POM supplementation varied in terms of form (pills/juice), dosage (50 ml–500 ml) and time of intervention (7 days–2 months) between studies. Among the reviewed articles, POM supplementation had an effect on the improvement of the following: whole body strength; feeling of vitality; acute and delayed muscle fatigue and soreness; increase in vessel diameter; blood flow and serum level of TAC; reduction in the rate of increase for HR, SBP, CK and LDH; support in the recovery of post-training CK, LDH, CRP and ASAT to their baseline levels; reduction of MMP2, MMP9, hsCRP and MDA; and increased activity of antioxidant enzymes (glutathione peroxidase and superoxide dismutase). In the majority of reviewed articles POM supplementation had a positive effect on a variety of parameters studied and the authors recommended it as a supplement for athletes and physically active bodies.


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