Piezoresistive behavior of DLP 3D printed CNT/polymer nanocomposites under monotonic and cyclic loading

Abstract

This study examines the piezoresistive behavior of MWCNT/polymer composites fabricated by the digital light processing (DLP) technique. A photocurable nanocomposite resin feedstock possessing low viscosity with excellent printability and high conductivity was developed for DLP 3D printing of bulk and cellular geometries. By optimizing the resin composition and synthesis route, electrical percolation was achieved at an ultra-low MWCNT loading of 0.01 phr (parts per hundred resin), providing a conductivity of 3.5 × 10−5 S m−1, which is significantly higher than the values reported in the extant works for similar nanocomposites. Reducing the MWCNT content also enhanced the piezoresistivity of the nanocomposite due to longer inter-MWCNT distances in the percolating conductive network. Under quasi-static tensile loading, the nanocomposite with 0.01 phr MWCNT loading showed gauge factors of 2.40 and 4.78, corresponding to the elastic and inelastic regime, respectively. Quasi-static cyclic tensile tests with constant strain amplitudes (within elastic regime) revealed that the response of the nanocomposite was affected by viscoelastic deformation, which caused significant changes in the material’s strain sensing performance between consecutive load cycles. Finally, the developed resin was used to realize a self-sensing gyroid lattice structure, and its strain and damage sensing capabilities were demonstrated.

Three Dimensionally Printed Biobased Electrodes: Ionic Liquid and Single-Walled Carbon Nanotube Hybrids in a Vegetable Oil Matrix for Soft Robotics

“…Figure 9c thermal stability data testifies to the excellent SWCNT integration into the resin formulations. 55 Weight loss curves almost overlap entirely, showing slightly increased char yields for samples 0.3%, 0.5%, and 1%. This increased char yield is attributed to the SWCNT loadings and charring of the sample.…”

Piezoresistive Porous Composites with Triply Periodic Minimal Surface Structures Prepared by Self-Resistance Electric Heating and 3D Printing

“…It was found that TPU-MWCNT could perform well as capacitive touch sensors in a piezoresistive flex mode under a variety of MWCNT loading conditions. Saadi et al [22] developed a nanocomposite resin with low viscosity for vat photopolymerization 3D printing and investigated the piezoresistive and mechanical behavior of nanocomposites. Due to the excellent printability of the developed resin, piezoresistive pressure sensors with different regimes of deformation were realized.…”

Electrical Anisotropy and its Mitigation in Conductive Polymers Printed by Digital Light Processing

“…These materials are selected because they display a low percolation threshold [14][15][16][17][18][19] and a high electrical conductivity [20][21][22][23][24] . A low percolation threshold allows the realization of conductive resins with a small amount of carbon material [25][26][27][28] to minimize UV absorption and scattering 29 .…”