Reshapeable, rehealable and recyclable sensor fabricated by direct ink writing of conductive composites based on covalent adaptable network polymers

Abstract

Covalent adaptable network (CAN) polymers doped with conductive nanoparticles are an ideal candidate to create reshapeable, rehealable, and fully recyclable electronics. On the other hand, 3D printing as a deterministic manufacturing method has a significant potential to fabricate electronics with low cost and high design freedom. In this paper, we incorporate a conductive composite consisting of polyimine CAN and multi-wall carbon nanotubes into direct-ink-writing 3D printing to create polymeric sensors with outstanding reshaping, repairing, and recycling capabilities. The developed printable ink exhibits good printability, conductivity, and recyclability. The conductivity of printed polyimine composites is investigated at different temperatures and deformation strain levels. Their shape-reforming and Joule heating-induced interfacial welding effects are demonstrated and characterized. Finally, a temperature sensor is 3D printed with defined patterns of conductive pathways, which can be easily mounted onto 3D surfaces, repaired after damage, and recycled using solvents. The sensing capability of printed sensors is maintained after the repairing and recycling. Overall, the 3D printed reshapeable, rehealable, and recyclable sensors possess complex geometry and extend service life, which assist in the development of polymer-based electronics toward broad and sustainable applications.

Strong and Tough Supramolecular Covalent Adaptable Networks with Room‐Temperature Closed‐Loop Recyclability

“…FT-IR spectra of all the supra-CANs and CANs show appearance of the CN stretching bands ascribed to the imine bonds, accompanied by the disappearance of the characteristic stretching bands of the aldehyde and amino groups, suggesting the quantitative conversion of the monomers into polyimines. [51][52][53][54][55][56][57][58][59][60][61] Figure 2a,b shows the FT-IR spectra zoomed in at the CO stretching region of the supra-CANs and CANs. The CO stretching bands of the sCAN-Ar and sCAN-Alk samples are, respectively, deconvoluted into two subpeaks.…”

Nanotechnology in Covalent Adaptable Networks: from Nanocomposites to Surface Patterning

“…The vitrimer/CNT nanocomposite were also applied in direct-ink-writing three-dimension (3D) printing to fabricate polymeric sensors with reshaping, repairing, and recycling abilities. 90 CNTs and nanoclay were incorporated into a polyimine CAN synthesized with terephthaldehyde and diethylenetriamine as monomers and tris(2-aminoethyl) amine as the cross-linker. The conductivity of the composites initially dropped with temperature owing to the disruption of conductive pathways by the bond exchange reaction but began to rise once the routes were rebuilt.…”

“…The composites were successfully repaired and reprocessed, while the fillers were recovered by dissolving the waste composites in dithiothreitol/DMF solution. The vitrimer/CNT nanocomposite were also applied in direct-ink-writing three-dimension (3D) printing to fabricate polymeric sensors with reshaping, repairing, and recycling abilities . CNTs and nanoclay were incorporated into a polyimine CAN synthesized with terephthaldehyde and diethylenetriamine as monomers and tris(2-aminoethyl) amine as the cross-linker.…”

Recyclable, Biobased Photoresins for 3D Printing Through Dynamic Imine Exchange

“…A few biobased CANs have been reported, usually consisting of associative bond exchange mechanisms, which are known as vitrimers. − Although a minority, there are some reports of 3D-printed materials that take advantage of CANs, with direct ink writing (DIW) being the most-used technique . − Nonetheless, a few reports that combine the use of VP and CANs have been documented . There have been a few examples of self-healing polymers used in 3DP so far, − but only a handful are compatible with VP. − …”