@Article{icces.2023.09357,
AUTHOR = {Dongze Yan, Jianxiang Wang, Lihua Shao},
TITLE = {Giant Flexoelectric Effect of Polymeric Porous Composite and Its  Applications},
JOURNAL = {The International Conference on Computational \& Experimental Engineering and Sciences},
VOLUME = {27},
YEAR = {2023},
NUMBER = {1},
PAGES = {1--2},
URL = {http://www.techscience.com/icces/v27n1/54089},
ISSN = {1933-2815},
ABSTRACT = {Non-uniform strains produce a localized break in the microscopic inverse symmetry of materials, which 
leads to the electromechanical coupling phenomenon known as flexoelectricity in all dielectric materials. 
However, the size-dependent flexoelectric effect typically only manifests at small scales. Creating a 
considerable flexoelectric output at the macroscopic scale remains a bottleneck. Micro- and nano-porous 
materials own a significant number of randomly distributed microscopic pores and ligamentous structures, 
which can deform non-uniformly under arbitrary forms of macroscopic loading. Moreover, since the small 
size effect of flexoelectricity, the entire flexoelectricity of the micro- and nano-porous materials will be much 
more significant than that of the solid counterpart. Here, a theoretical framework of porous structures to 
predict the flexoelectric electric output is presented, and a quantitatively analysis to reveal the major 
governing parameters is performed [1]. Porous polydimethylsiloxane (PDMS) and polyvinylidene fluoride 
(PVDF) are fabricated to verify the theoretical models. Based on the theory, a stacked-and-twisted porous 
composite is fabricated with PDMS and nano-copper-calcium-titanate (CCTO) particles to improve the 
flexoelectric coefficient of ligaments, combining with the optimized aspect ratio, compression-torsion 
coupling deformation mode and multiple induction electrodes to increase the flexoelectric output [2]. Its 
mass- and deformability-specific flexoelectricity is four orders of magnitude more than that of the matrix 
material, and the density-specific equivalent piezoelectric coefficient reaches 100 times greater than that of 
the piezoelectric ceramic lead-zirconate-titanate. Its stress-strain relations and electrical output remain 
stable under 1,000,000 times of cyclic loads. Finally, we demonstrate that the porous composite exhibits an 
efficient omnidirectional electromechanical coupling ability for applications as sensor and strain gradient 
electric generator (SGG) – a portable sample can charge mobile phones and blue tooth headsets.},
DOI = {10.32604/icces.2023.09357}
}