Ultra-wide and Linear Range Flexible Piezoelectric Sensor Based on PVDF/BNNS Composites

Flexible piezoelectric sensors have attracted significant attention in the field of structural health monitoring (SHM) owing to their excellent frequency response capability and conformal attachment to complex surfaces. However, the conventional blending methods often fail to achieve uniform dispersion and ordered orientation of nanofillers within polymer matrices, which limits the sensitivity and linear measurement range. To address this issue, a fabrication strategy for flexible piezoelectric sensors based on the induced orientation by shear flow-is proposed. During the blade coating process, a strong shear flow field is generated, which induces high-modulus two-dimensional boron nitride nanosheets (BNNSs) to form a highly ordered parallel lamellar structure within the polyvinylidene fluoride (PVDF) matrix. This architecture not only constructs an efficient stress transfer pathway, but also significantly enhances the deformation resistance and structural stability of the composite. The fabricated PVDF/BNNS composite piezoelectric sensor achieves an ultra-wide linear measurement of 0-619 MPa, approximately 1.6 times that of pristine PVDF, while maintaining a high voltage sensitivity of 16.6 mV MPa -1 , which is about 2.3 times higher than that of pure PVDF based sensor. Furthermore, the sensor exhibits excellent response capability for broadband vibration signals in the frequency range of 20-100 Hz, meaning its practical potential for intelligent monitoring and condition sensing of industrial equipment.