Ultrathin and Ultrasensitive Printed Carbon Nanotube-Based Temperature Sensors Capable of Repeated Uses on Surfaces of Widely Varying Curvatures and Wettabilities

Abstract

In this paper, we demonstrate the ability to fabricate temperature sensors by using our newly developed carbon nanotube–graphene oxide (CNT-GO) ink to print temperature-sensitive traces on highly flexible, thin, and adhesive PET (polyethylene terephthalate) tapes, which in turn are integrated on surfaces of different curvatures and wettabilities. Therefore, the strategy provides a facile, low-cost, and environmentally friendly method to deploy printed temperature sensors on surfaces of widely varying curvatures and wettabilities. The temperature sensing occurs through a thermally induced change in the resistance of the printed traces and we quantify the corresponding negative temperature coefficient of resistance (α) for different conditions of curvatures and wettabilities. In addition, we identify that at low temperatures (below 15 °C), the printed traces show an α value that can be as large (in magnitude) as 60 × 10–3/°C, which is several times higher than the typical α values reported for temperature sensors fabricated with CNT or other materials. Furthermore, we achieve the printing of traces that are only 1–3 μm thick on a 50 μm-thick PET film: therefore, our design represents an ultrathin additively fabricated temperature sensor that can be easily integrated for wearable electronic applications. Finally, we show that despite being subjected to repeated temperature cycling, there is little degradation of the CNT-GO microarchitectures, making these printed traces capable of repeated uses as potential temperature sensors.

Temperature Detectable Surface Coating with Carbon Nanotube/Epoxy Composites

“…In Table 1 , we compared the TCR values obtained from the present study against other temperature sensors. This comparison confirms that the resistances of the CNT/EP coating were measured as functions of temperature [ 33 , 34 , 35 , 36 , 37 , 38 ].…”

“…In Table 1, we compared the TCR values obtained from the present study against other temperature sensors. This comparison confirms that the resistances of the CNT/EP coating were measured as functions of temperature [33][34][35][36][37][38]. Repeatability is one of the major factors required for long-term stable use of temperature sensors.…”

Boron Nitride Nanotube–Salt–Water Hybrid: Toward Zero-Dimensional Liquid Water and Highly Trapped Immobile Single Anions Inside One-Dimensional Nanostructures

“…Nanotubes (e.g., carbon nanotubes or CNTs and boron nitride nanotubes or BNNTs), characterized as hollow tubes with internal diameters ranging from a few to tens of nanometers have emerged as the most remarkable one-dimensional (1D) nanostructures that have found wide-scale application in fabrication of sensors, transistors, conductors, batteries, energy-storage materials, light-emitting diodes, lithium-ion batteries, supercapacitors, light-weight composites, and flexible electronics as well as in applications such as waste-water treatment, water purification, chromatography, voltammetry, solid-phase extraction of drugs and biomolecules, drug targeting, controlled drug release, disease diagnosis and treatment, enabling antibacterial and antifungal properties, and many more. − While many of these applications use these nanotubes as filler materials for improving the properties of certain macroscopic materials (e.g., adding CNTs for improving the mechanical, thermal, and electric properties of CNT-polymer-based nanocomposites − or using CNTs to prepare mixtures/pastes that can be used for printing temperature sensors , and fabricating antibacterial coatings , ), more exciting classes of studies and future applications (e.g., use as high-performance membranes, or use in futuristic water treatment technologies, or promoting specific chemical reactions) involve probing the properties and transport of water, ions, and other species (e.g., alcohol, dyes, etc.) remaining encapsulated within or transporting through a single CNT or BNNT. − For example, water encapsulated within CNTs or BNNTs demonstrates a 1D structure with most fascinating properties. − Similarly, gas-filled CNTs have been touted to be used as nanoresonators with unprecedented properties. − Also, there has been massive interest in probing the behavior of nanotube-encapsulated salt systems. − One such example, where other species have been closely integrated with nanotubes, is nanotube–molecule-based hybrid systems.…”

Light-Energy-Harvested Flexible Wireless Temperature-Sensing Patch for Food Cold Storage

“…Flexible electronics with high adaptability and easy deployment has been widely applied. − The flexible electronics usually consists of a flexible substrate, the circuits assembled on a flexible substrate, and the electronic components or modules. The flexible substrate could be films such as polyimide (PI), poly­(ethylene terephthalate) (PET), and poly­(ethylene naphthalate) (PEN). − The circuits could be various metals such as gold (Au), silver (Ag), and copper (Cu) . The electronic components or modules could be silicon-based or organic thin film-based small electronic components or the miniature electronic modules made by conventional print circuit boards (PCBs) .…”