Aqueous MXene/Xanthan Gum Hybrid Inks for Screen‐Printing Electromagnetic Shielding, Joule Heater, and Piezoresistive Sensor

Abstract

Although several patterning methods, such as lithography, spray-masking and laser cutting, have been used for facile fabrication of those devices, the complicated processing and excessive material consumption in these protocols limit the scalable production of flexible devices. [4] So far, it remains a significant challenge to achieve multifunctional devices such as EMI shielding, [5] Joule heater, [6] sensor, [7][8][9] radio frequency identification (RFID) tags, [10] and energy storage unit [11] by using simple and low-cost methods. In addition, seeking a suitable material is vital to develop and design high-performance multifunctional devices in low cost.Recent progress in liquid-phase exfoliation of two-dimensional (2D) nanomaterials has highlighted the rational design of functional inks for additive manufacturing of high-performance devices with complex architectures based on printing strategies, such as screen printing, gravure printing and inkjet printing. [12] Screen printing among them is of critical importance to manufacture integrated multifunctional devices by formulating functional inks, without using expensive and complicate equipment. [13] Specially, screen printing provides the highest deposition rate (per unit time deposition material weight) than other printing technologies. [14] One of the main challenges lies in formulation of functional inks with appropriate rheological properties, which are prerequisite for screenprinting multifunctional devices with high resolution. [15,16] As a new family of 2D layered transition metal carbides or nitrides, MXenes have become promising candidate for formulation of printable inks because of their remarkable electronic, optical, and mechanical properties. [17] Generally, MXenes are usually synthesized by selectively etching A layer in the precursor of MAX phase. They can be represented by M n+1 X n T x , where M is the early transition metal, X stands for carbon and/ or nitrogen, and T x represents the terminal hydroxyl, oxygen, or fluorine groups. [18,19] As a result, MXenes offer solution processing capabilities owing to their superior hydrophilicity and high negative surface charge. [20] Clay-like behavior of MXene slurry and the formation of stable colloidal suspension have thus facilitated the fabrication of conducting films, nanocomposites, coatings and fibers for applications in energy MXenes have exhibited potential for application in flexible devices owing to their remarkable electronic, optical, and mechanical properties. Printing strategies have emerged as a facile route for additive manufacturing of MXene-based devices, which relies on the rational design of functional inks with appropriate rheological properties. Herein, aqueous MXene/xanthan gum hybrid inks with tunable viscosity, excellent printability, and long-term stability are designed. Screen-printed flexible MXene films using such hybrid inks exhibit a high conductivity up to 4.8 × 10 4 S m −1 , which is suitable to construct multifunctional devices mainly including electromagnetic shield...

Enhanced Electromagnetic Shielding and Thermal Management Properties in MXene/Aramid Nanofiber Films Fabricated by Intermittent Filtration

“…Figure a shows the time-dependent temperature of the MXene/ANF composite films at the low direct voltages from 0.5 to 4 V. Due to the efficient conductive pathway, the surface temperature of the film increases continuously with the increase of the load voltage and reaches a steady-state temperature within 10 s. The infrared thermal images exhibit a uniform temperature distribution; the steady temperatures change from 31.6 at 0.5 V to 89.0 °C at 4 V (Figure d), indicating the high-efficiency electrothermal conversion capacity. According to the following equation Q = U 2 R t where Q , U , R , and t stand for the Joule heat, load voltage, resistance, and working time, respectively . The steady-state temperatures of the film surface are linearly fitted to the square of the voltages (Figure b), which proves that the electrothermal conversion performance is consistent with the theoretically expected results.…”

From MXene Trash to Ultraflexible Composites for Multifunctional Electromagnetic Interference Shielding

“…The MS/WPU composite film heaters also presented excellent performance at low power consumptions. The I – V curve of 70 wt % MS/WPU composite films was practically linear, as shown in Figure e, indicating that the substance complies with Ohm’s law and has a steady resistance . The equilibrium temperature of the 70 wt % MS/WPU composite films exhibited a linear relationship with the input power density (Figure f).…”

“…The I−V curve of 70 wt % MS/WPU composite films was practically linear, as shown in Figure 5e, indicating that the substance complies with Ohm's law and has a steady resistance. 63 The equilibrium temperature of the 70 wt % MS/WPU composite films exhibited a linear relationship with the input power density (Figure 5f). The steady-state temperature versus input power density was used to define the heat performance value (Hp = dT/dP) 64 of the composite heater.…”

3D Printing of Stretchable, Adhesive and Conductive Ti3C2Tx-Polyacrylic Acid Hydrogels

“…Particularly, Ti 3 C 2 T x , as a representative MXene material, possesses high electrical conductivity (10,000 S cm −1 ), superior hydrophilicity [ 15 , 16 ], as well as good mechanical performance due to the presence of M-N or M-C bonds. Functional groups (=O, -OH, and -F) on the MXene surface [ 17 ] enables MXenes with excellent dispersibility, which can be processed by multiple manufacturing techniques [ 18 , 19 , 20 ], involving screen-printing [ 21 , 22 ], stamping [ 23 ], and spraying [ 24 ]. However, these processing techniques are usually limited by multiple factors, such as low-resolution, two-dimensional, and low aspect ratio [ 25 ].…”