Advanced Boiling–A Scalable Strategy for Self-Assembled Three-Dimensional Graphene

et al. 2021

J. Am. Chem. Soc.

Cellulose is the most abundant renewable natural polymer on earth, but it does not conduct electricity, which limits its application expansion. The existing methods of making cellulose conductive are combined with another conductive material or high-temperature/high-pressure carbonization of the cellulose itself, while in the traditional method of sulfuric acid hydrolysis to extract nanocellulose, it is usually believed that a too high temperature will destroy cellulose and lead to experimental failure. Now, based on a new research perspective, by controlling the continuous reaction process and isolating oxygen, we directly extracted intrinsically conductive cellulose nanofiber (CNF) from biomass, where the confined range molecular chains of CNF were converted to highly graphitized carbon at only 90 °C and atmospheric pressure, while large-scale twisted graphene films can be synthesized bottom-up from CNFene suspensions, called CNFene (cellulose nanofiber–graphene). The conductivity of the best CNFene can be as high as 1.099 S/cm, and the generality of this synthetic route has been verified from multiple biomass cellulose sources. By comparing the conventional high-pressure hydrothermal and high-temperature pyrolysis methods, this study avoided the dangerous high-pressure environment and saved 86.16% in energy. These findings break through the conventional notion that nanocellulose cannot conduct electricity by itself and are expected to extend the application potential of pure nanocellulose to energy storage, catalysis, and sensing.

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Confined Chemical Transitions for Direct Extraction of Conductive Cellulose Nanofibers with Graphitized Carbon Shell at Low Temperature and Pressure

et al. 2021

J. Am. Chem. Soc.

Section: Bubbles In Liquid Mediamentioning

confidence: 99%

“…Bubbles form in boiling water has attracted many applications toward the production of materials. [ 34,40–42 ] For example, Ahn et al. proposed an advanced boiling strategy to realize the scalable preparation of foam‐like graphene networks (Figure 2c).…”

Section: Bubbles In Liquid Mediamentioning

confidence: 99%

Bubble‐Mediated Mass Production of Graphene: A Review

Shi

et al. 2022

Adv Funct Materials

The large-scale industrial applications of graphene highly depend on its mass production with efficiency (high-yield, time-saving, and low-cost) and controllability (high-quality, safe, and environmentally friendly). However, this requirement can hardly be satisfied by incumbent chemical exfoliation methods exploiting liquid-solid interactions. Recently, many studies have demonstrated that the usage of bubbling as a new tool makes a big difference in multiple aspects of graphene production. Benefiting from their unique properties, the bubbles can be employed as the driving force to cleave graphite layers for graphene preparation or as the favorite interface for graphene growth at a high temperature. Therefore, the bubble-mediated technique represents a new strategy promising to achieve efficient and controllable preparation of graphene. Here, the formation and evolution of bubbles in liquid media are first analyzed. Then, two routes including "top-down" and "bottom-up" toward mass production of graphene with the assistance of bubbles are summarized and discussed. This review sheds light on the introduction of gas to realize the mass production of graphene for the development of graphene's applications on large scale.

“…Graphene, as a typical material in the family of two-dimensional materials, has soft carbon-based properties enabling it to display a remarkably high specific surface area, unique electrical, mechanical, and optical properties, high carrier density, and ultrathin form factors, which endow it with great potential for sensing applications. , In 2014, Tour et al first prepared laser-induced graphene (LIG) on a polymer surface with a laser direct writing technique . This method allows easy access to patterned customized LIG, whose porous microstructure and excellent electrical and thermal properties make it a highly effective and flexible electrode active material.…”

Section: Introductionmentioning

confidence: 99%

Humidity-Based Human–Machine Interaction System for Healthcare Applications

Zou

Tao

ACS Appl. Mater. Interfaces

et al. 2022

Human–machine interaction (HMI) systems are widely used in the healthcare field, and they play an essential role in assisting the rehabilitation of patients. Currently, a large number of HMI-related research studies focus on piezoresistive sensors, self-power sensors, visual and auditory receivers, and so forth. These sensing modalities do not possess high reliability with regard to breathing condition detection. The humidity signal conveyed by breathing provides excellent stability and a fast response; however, humidity-based HMI systems have rarely been studied. Herein, we integrate a humidity sensor and a graphene thermoacoustic device into a humidity-based HMI system (HHMIS), which is capable of monitoring respiratory signals and emitting acoustic signals. HHMIS has a practical value in healthcare to assist patients. For example, it works as a prewarning system for respiratory-related disease patients with abnormal respiratory rates, and as an artificial throat device for aphasia patients. Achieved based on a laser direct writing technology, this wearable device features low cost, high flexibility, and can be prepared on a large scale. This portable non-contact HMMIS has broad application prospects in many fields such as medical health and intelligent control.