Direct Pen Writing of Adhesive Particle-Free Ultrahigh Silver Salt-Loaded Composite Ink for Stretchable Circuits

Abstract

In this article, we describe a writable particle-free ink for fast fabrication of highly conductive stretchable circuits. The composite ink mainly consists of soluble silver salt and adhesive rubber. Low toxic ketone was employed as the main solvent. Attributed to ultrahigh solubility of silver salt in short-chain ketone and salt-assisted dissolution of rubber, the ink can be prepared into particle-free transparent solution. As-prepared ink has a good chemical stability and can be directly filled into ballpoint pens and use to write on different substrates to form well adhesive silver salt-based composite written traces as needed. As a result of high silver salt loading, the trace can be converted into highly conductive silver nanoparticle-based composites after in situ reduction. Because of the introduction of adhesive elastomeric rubber, the as-formed conductive composite written trace can not only maintain good adhesion to various substrates but also show good conductivity under various deformations. The conductivity of written traces can be enhanced by repeated writing-reduction cycles. Different patterns can be fabricated by either direct handwriting or hand-copying. As proof-of-concept demonstrations, a typical handwriting heart-like circuit was fabricated to show its capability to work under different deformations, and a pressure-sensitive switch was also manufactured to present pressure-dependent change of resistance.

Percolation threshold-inspired design of hierarchical multiscale hybrid architectures based on carbon nanotubes and silver nanoparticles for stretchable and printable electronics

“…In order to accelerate the rate of absorption and reduction, the film should be thin enough by tuning the amounts of CNTs/SBS solution. The conductivity of Ag NPs/polystyrene-block-polyisoprene-block-polystyrene composite [31] and graphene/nature rubber [16] is relatively low. The surface of the composites is damaged by common tape to scrap off the reduced Ag NPs, leading to the slight decrease in concentration of Ag NPs.…”

Fabrication of a Quasicrystal Electrode at a Low Processing Temperature via Electrohydrodynamic and Transfer Printing for use in Multifunctional Electronics

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temperature or with heating at less than 60 °C for 1 h. This is not only one of the important conditions for determining the degree of aggregation of silver, but also for controlling the binding energy of silver or the density of silver that would be higher at the bottom. [8][9][10]21,22] With this approach, we can fabricate flexible tiled circuits, water-proof light emitting diodes (LEDs) without any additional restricting condition, and this transferred electrode would be freestanding, attached to various uneven interface operated LEDs. [8][9][10]21,22] With this approach, we can fabricate flexible tiled circuits, water-proof light emitting diodes (LEDs) without any additional restricting condition, and this transferred electrode would be freestanding, attached to various uneven interface operated LEDs.

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“…[11][12][13]15,16,20] We propose a patterning mechanism that offers a closer nozzleto-substrate distance than conventional EHD printing operating at less than 100 µm to easily charge the electron moving nozzle with ground (GNR) in spite of using an insulated PET substrate (Figure 1a,b, inset). Examples of such include roll-to-stamp printing, [1,4] screen printing, [5] dropon-demand printing, [6][7][8] direct pen writing [9,10] and electrohydrodynamic (EHD) printing. This electrode resolution was controlled by increasing the printing speed ( Figure S1a,b, Supporting Information).…”

“…The first step is to pattern a silver trace after printing the e-NDP solution on a PET substrate coated with silver trifluoroacetate (STA) (18 wt%) dissolved in volatile tetrahydrofuran (THF). [9,13,15,17] In the present work, we propose an advanced patterning method that implements electrohydrodynamic narrow nozzleto-substrate distance printing (e-NDP). This solution is overpatterned on the position of the silver trace at a low temperature of 60 °C for 1 h. As the experimental equipment has a function of automatically performing overpatterning, misalignment could not occur during same-trace-position printing.…”

“…Examples of such include roll-to-stamp printing, [1,4] screen printing, [5] dropon-demand printing, [6][7][8] direct pen writing [9,10] and electrohydrodynamic (EHD) printing. [9,13,15,17] In the present work, we propose an advanced patterning method that implements electrohydrodynamic narrow nozzleto-substrate distance printing (e-NDP). The necessary equipment operates using various concepts to traverse the nozzle-to-substrate distance, including electrospraying, [5] near-field electrospinning, [11][12][13]15,17] and nanodripping.…”