Direct ink writing of flexible electronic circuits and their characterization

Abstract

The present work discusses the fabrication of low-cost, reliable and durable flexible electronic circuits from conductive carbon paste on flexible polyethylene terephthalate (PET) substrate using microdispensing direct ink write technique. Printing parameters such as pressure, substrate speed and gap size are optimized through Box-Behnken experimental design technique to achieve the desired quality of prints (patterns). For the nozzle with an inner diameter of 200 µm, the system is able to produce pattern line width ranging from 198 µm to 295 µm, respectively. Based on optimized parameters, circuits such as foil grid and rectangular spiral are printed on a flexible PET substrate. The deposited patterns of circuits are morphologically characterized by optical microscopy and scanning electronic microscopy. Current-Voltage (I-V) characteristic is performed to evaluate the conductive performance of circuits. The sensitivity of circuits to bending is assessed by studying resistance response under fully bend and unbend angle of 90° and 0°. Durability and reliability of circuits are analyzed by subjecting circuits to continuous 500 bend cycles and study its resistance response. The analysis revealed that these direct ink write circuits are reliable, durable and stable in performance and are applicable to the flexible electronic application.

Multi-Response Optimization of Tensile Creep Behavior of PLA 3D Printed Parts Using Categorical Response Surface Methodology

“…Experiments were designed using a categorical central composite design (CCCD) based on Response surface methodology (RSM). The purpose of applying this design is to determine the interaction between the independent variables, model the system mathematically, and to reduce experimental runs [ 39 , 40 ]. It is a second-order fractional factorial design having center points and axial points added to the full factorial design (2 k ), where k is a number of factor, and 2 is the number of levels.…”

A Review on Materials and Technologies for Organic Large‐Area Electronics

“…[ 350 ] DIW includes dispensing methods such as microdispensing and electrostatic‐force‐assisted dispensing. [ 351,352 ] Another 3D printing technology is the laser powder‐bed fusion (PBF). [ 351,352 ] Instead of using filaments and viscous inks as feedstock materials, PBF techniques use loose powders and binders, which are fused together through selective laser sintering (SLS), selective laser melting (SLM) or through electron beam melting (EBM).…”

“…[ 351,352 ] Another 3D printing technology is the laser powder‐bed fusion (PBF). [ 351,352 ] Instead of using filaments and viscous inks as feedstock materials, PBF techniques use loose powders and binders, which are fused together through selective laser sintering (SLS), selective laser melting (SLM) or through electron beam melting (EBM). Other processes such as stereolithography (SLA), digital light projection (DLP), Polyjet, and two‐photon polymerization (2PP) demand the use of UV curable photopolymers and resins, which are selectively crosslinked through computer‐aided irradiation.…”

“…Other processes such as stereolithography (SLA), digital light projection (DLP), Polyjet, and two‐photon polymerization (2PP) demand the use of UV curable photopolymers and resins, which are selectively crosslinked through computer‐aided irradiation. [ 351,352 ]…”

“…[ 351 ] Abas and co‐workers used microdispensing DIW to deposit a conductive carbon paste on PET. [ 351 ] To tune the rheology of the carbon paste and turn it more suitable for dispense printing the carbon paste was slightly modified resorting to PVA. The electrical conductivity and mechanical resilience of the fabricated device were evaluated and the results proved that this technique was adequate to obtain reliable, durable, and stable operative circuits.…”