β‐Phase‐Rich Laser‐Induced Hierarchically Interactive MXene Reinforced Carbon Nanofibers for Multifunctional Breathable Bioelectronics (Adv. Funct. Mater. 5/2022)

Abstract

Breathable Bioelectronics In article number 2107969, Jae Y. Park and co‐workers develop hierarchically interactive carbon nanofibers from β‐phase rich dehydrofluorinated MXene‐poly(1,1‐difluoroethylene) electrospun nanofibers via laser‐induced carbonization. The β‐phase is converted into an sp2‐hybridized graphitic structure by cyclization/cross‐linking decomposition of hydrogen fluoride and transforms into a conjugated carbon structure during carbonization. The approach generates flexible carbon nanofibers with high carbon yield, conductivity, and stability appropriate for engineering skin‐compatible and breathable electrophyological bioelectronics to develop human‐machine interfaces.

Micro‐/Nanohierarchical Structures Physically Engineered on Surfaces: Analysis and Perspective

“…Despite these limitations, owing to the strong advantages of top-down processes (i.e., precise patternability, reproducibility, and unifor-mity), rationally designed micropatterns can be combined with different components (micropattern-micropattern, [8,9,12,14,17] micropattern-wrinkle, [62] micropattern-nanopattern, [69,70] and micropattern-random structure [71][72][73] combinations) to produce physically engineered hierarchical structures with superior characteristics. Micropattern-based hierarchical structures have potential applications in fields such as sensors, [74] dry/wet adhesives, [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] optical security patterns, [69,70] bioelectronics, [73,75] wearable devices, [72,75] and energy storage devices. [72] In the following paragraph, we summarize the strategies used to construct practically applicable micropattern-based hierarchical structures and overcome the limitations of single-micropattern structures.…”

“…LIC has also been used by other research groups for the scalable fabrication of micropattern-random hierarchical structures as micro supercapacitors for high-performance energy storage (Figure 2i). [71][72][73][75][76][77] Advances in patterning using CO 2 laser processing to fabricate micropattern-random hierarchical structures presented potential applications in wearable bioelectronics for diverse physiological signal measurements, such as measurements of electrocardiogram (ECG) and biochemical parameters (e.g., glucose, calcium, and pH) of sweat. [75,77] CO 2 laser processing technique described above is not the only method used to fabricate hierarchical structures.…”

A Breathable, Passive‐Cooling, Non‐Inflammatory, and Biodegradable Aerogel Electronic Skin for Wearable Physical‐Electrophysiological‐Chemical Analysis

“…Such limitations prevent sweat evaporation off the skin and limit the emission of volatile organic components (VOCs), which lead to skin irritation and inflammation. [ 27–29 ] Also, typical elastomers are neither disposable nor recyclable, leading to more plastic waste and increased environmental burden. [ 30 ] The next generation of high‐quality E‐skin devices with enhanced comfort and practicality should therefore be breathable, biodegradable, biocompatible, and withstand mechanical deformation, especially for long‐term on‐body use.…”

MXene/Fluoropolymer‐Derived Laser‐Carbonaceous All‐Fibrous Nanohybrid Patch for Soft Wearable Bioelectronics

“…Among the many carbon nanomaterials, owing to their unique properties such as excellent electronic conductivity, mechanical strength, large working surface area, and breathability, 3D electrospun, and laser‐carbonized CNFs have recently gained considerable attention. [ 20,30 ] The use of CNFs as a support for metal/metal‐oxide nanocatalysts generally provides favorable characteristics for promoting effective electrocatalytic reactions. Particularly, the 3D conductive networks of CNFs offer a high active electrode area and porosity, which greatly stimulates internal electron and mass transfer.…”

“…Hybrid CNFs produced from electrospun MXene and fluoropolymers (e.g., PDFE‐poly(1,1‐difluoroethylene) nanofibers (MFNFs)) have attracted considerable attention owing to their high carbon efficiency, mechanical stability, and durability. [ 30 ] With MXene impregnation into the PDFE electrospinning solution, continuous hydrogen (H) bonds are formed between the OH, O, and F groups of MXene with the H and F atoms in the PDFE β‐phase because of electrostatic attraction. [ 33 ] The H‐bond linkage between MXene and PDFE stabilizes and aligns the all‐trans conformation (TTTT).…”