Mask-Free Preparation of Patterned Carbonized Carboxymethyl Cellulose on Fabrics for Flexible Electronics

Abstract

Fabric-based flexible electronics have promising applications in biomedicine, soft robots, and human–machine interfaces. However, fabrication of flexible electronics on fabrics in a high throughput and scalable manner without significantly sacrificing the benefits of fabrics is still a challenge. To address this, a laser direct writing (LDW)-based technique is developed for the mask-free fabrication of flexible electronics on fabrics. Carboxymethyl cellulose (CMC) is chosen as the precursor for the carbon electrode formed by LDW on the fabrics because CMC is water soluble, which is convenient to be processed and able to be mixed with inorganic precursors to form composites. Flexible pressure sensor based on LDW-carbonized CMC (CCMC) has a sensitivity of −0.25 kPa–1 within 5 kPa, response time of 0.5 s, and detectable limit of 140 Pa. The specific capacitance of the LDW prepared Mo x O y /CCMC electrode is 12.8 mF/cm2. The LDW Mo x O y /CCMC composite-based flexible all-solid-state supercapacitor has a capacitance of 1.095 mF/cm2, with a high flexibility and mechanical durability.

Wearable and Stretchable Strain Sensors: Materials, Sensing Mechanisms, and Applications

“…Laser direct writing (LDW) has been recently introduced as an effective and scalable process for the manufacturing of wearable sensors. [154][155][156][157][158] For instance, LDW was used to develop stretchable strain sensor arrays by turning Ecoflex elastomer into silicon carbide conductive patterns through the localized laser irradiation. [158] Apart from the polymeric supporting materials, natural fibers, yarns, and fabrics have been activated by conductive materials through techniques such as carbonization process, dip-coating, bar coating, ultrasonication, and vacuum filtration.…”

Recent Developments of Carboxymethyl Cellulose

“…CMC provides excellent mechanical properties during application and ensures safer wound care in wet conditions. Moreover, to monitor health and biomedicine activity, CMC is used as carbonized CMC (smart fabrics) on flexible electronics [ 173 ].…”

3D Printing of Flexible Strain Sensor Array Based on UV‐Curable Multiwalled Carbon Nanotube/Elastomer Composite

“…In contrast to the metal‐based strain sensor working on strain‐induced geometry change, nanomaterial‐based strain sensors respond to applied deformation by contact and tunneling resistance changes among individual nanomaterials, thus leading to much enhanced sensitivity, strain detection range, and response speed. Up to now, a collection of fabrication techniques are put forward to develop the flexible strain sensors, including photolithography, [ 13,14 ] laser direct writing, [ 15–19 ] stencil printing, [ 20 ] screen printing, [ 21 ] inkjet printing, [ 22 ] and 3D printing. [ 3,23–27 ] Among these fabrication techniques, 3D printing or additive manufacturing is brought into focus for its simple process, less labor, capability to fabricate customized complex 3D patterns and structures in maskless manners.…”