Continuous Three-Dimensional Printing of Architected Piezoelectric Sensors in Minutes

Abstract

Additive manufacturing (AM), also known as three-dimensional (3D) printing, is thriving as an effective and robust method in fabricating architected piezoelectric structures, yet most of the commonly adopted printing techniques often face the inherent speed-accuracy trade-off, limiting their speed in manufacturing sophisticated parts containing micro-/nanoscale features. Herein, stabilized, photo-curable resins comprising chemically functionalized piezoelectric nanoparticles (PiezoNPs) were formulated, from which microscale architected 3D piezoelectric structures were printed continuously via micro continuous liquid interface production (μCLIP) at speeds of up to ~60 μm s-1, which are more than 10 times faster than the previously reported stereolithography-based works. The 3D-printed functionalized barium titanate (f-BTO) composites reveal a bulk piezoelectric charge constant d33 of 27.70 pC N-1 with the 30 wt% f-BTO. Moreover, rationally designed lattice structures that manifested enhanced, tailorable piezoelectric sensing performance as well as mechanical flexibility were tested and explored in diverse flexible and wearable self-powered sensing applications, e.g., motion recognition and respiratory monitoring.

High-Speed and High-Resolution 3D Printing of Self-Healing and Ion-Conductive Hydrogels via μCLIP

“…PVA and PAA were selected to form the IPN hydrogel system because of the high mobility of polymer chains and extensive bond-forming groups (carboxyl and hydroxyl groups). , Upon physical damage, the PVA chain diffusion across the interface can form new hydrogen bonds not only among its own hydroxyl groups (−OH) ,, but also with the carboxylic groups (−COOH) of PAA, hence, contributing to the SH ability (Figure b). In previously reported hydrogel systems without the addition of ferric ions (Fe 3+ ), the PVA’s concentration needs to be raised to above 15–30 wt % to enable satisfactory SH effect , which significantly increases the resin’s viscosity, consequently leading to failure of high-resolution printing by μCLIP . Alternatively, to improve the SH capabilities without the demand for high PVA concentration, ferric chloride was introduced into the system to form the dynamic ionic bonds between ferric ions and carboxyl groups of PAA in addition to the hydrogen bonds (Figure b). ,, By combining these two-pronged strategies, the SH efficiency can efficiently reach over 90% (both stress and strain) within a reasonable healing time frame (<4 h), even for the resin with PVA’s concentration as low as 9 wt %.…”

“…In previously reported hydrogel systems without the addition of ferric ions (Fe 3+ ), the PVA's concentration needs to be raised to above 15−30 wt % to enable satisfactory SH effect 36,39 which significantly increases the resin's viscosity, consequently leading to failure of high-resolution printing by μCLIP. 49 Alternatively, to improve the SH capabilities without the demand for high PVA concentration, ferric chloride was introduced into the system to form the dynamic ionic bonds between ferric ions and carboxyl groups of PAA in addition to the hydrogen bonds (Figure 1b). 21,50,51 By combining these two-pronged strategies, the SH efficiency can efficiently reach over 90% (both stress and strain) within a reasonable healing time frame (<4 h), even for the resin with PVA's concentration as low as 9 wt %.…”

Additive manufacturing: pushing the boundaries of piezoelectric materials

“…(μCLIP-based) 3D printing procedure for rapid production of piezoelectric metamaterials. [17] The basic principle and equipment are shown in Fig. 2 (a).…”

“…[22] Page 8 of 13 https://mc03.manuscriptcentral.com/matlab and equipment. [17] Copyright 2022, American Association for the Advancement of Science. (b) the basic piezoelectric metamaterial: a 3D network consisted of piezoelectric, conductive and structural phases;…”

Vibrations and waves in soft dielectric elastomer structures

“…The reports on experimental fabrications of soft DE PCs and metamaterials, especially with active or smart control capability, are still limited, which restricts the real applications of the DE PC-based devices. The potential solution to the high-precision shaping and patterning of PCs and metamaterials is the novel 3D printing techniques[160][161][162]. Therefore, developing fast and high-precision fabrication techniques for DE PCs and metamaterials is a key and challenging issue in the future.…”