Hollow Nanospheres of Red Phosphorus for Fireproof Flexible Sensors Fabricated via 3D Printing

Abstract

High-power and high-temperature applications have brought increased demand for electrical sensing systems; however, conventional sensors have often been designed without consideration for stability in extreme environments (e.g., fire). Red phosphorus (RP) is a highly effective commercial flame retardant; however, its sensitive properties and large size predispose it to spontaneous combustion during shearing and make it difficult to combine with direct inkjet writing technology carrying micron-sized pinholes to fabricate sophisticated sensor devices. Here, bulk commercial red phosphorus (C-RP) is converted into red phosphorous hollow nanospheres (RPHNs). The ingeniously designed nanostructure effectively circumvents the flammability of C-RP extrusion processes and the risk of clogging the printing needle, and a fireproof pressure-sensitive sensor has been successfully fabricated. A load of RPHNs into a sensor matrix improves the moldability and fire safety properties. And with the assistance of the rapid charring mechanism, the peak of the heat release rate of the fireproof pressure-sensitive sensor is reduced by 58.9% compared to the pure matrix and withstands seven 2-s repetitive ignitions, thus allowing the sensor to respond continuously to flame stimulation. This work provides a broad perspective on the design of fireproof sensors and the application of red phosphorus hollow nanospheres.

A Gas-Steamed Route to Mesoporous Open Metal–Organic Framework Cages Enhancing Flame Retardancy and Smoke Suppression of Polyurea

“…The acceptable mechanical property is mainly ascribed to the better interfacial compatibility between the filler and the polyurea matrix. The open structure of OZCs enhances the interfacial interaction between the filler and the polymer chains, and OZCs and Co 3 O 4 cooperate to play the enhancement mechanism of dimension dislocation as well. , Notably, the blended polyurea composites with nano-Co 3 O 4 showed the worst mechanical properties (Table S9). On the one hand, this is due to the complete removal of ligands during the evolution of ZIF-67 into nano-Co 3 O 4 , while the ligands facilitate the enhancement of the compatibility between the filler and the polyurea matrix.…”

Coordination bond cleavage of metal–organic frameworks and application to flame-retardant polymeric materials

“…3l and m). 51,52 This dimensional mismatch structure can effectively avoid the early fracture of the EP composites due to the excessive stress caused by the local filler agglomeration during mechanical loading. 53,54 3 Function of cleft MOFs and the application as FRs…”

Renaissance of elemental phosphorus materials: properties, synthesis, and applications in sustainable energy and environment

“…26 Amorphous red-P is the most versatile phosphorus allotrope. Because of its low cost, environmental friendliness, availability, and stability, it finds applications in various fields such as flame retardants, 27 energy harvesting, 23,28 ion storage, 29 and pollution sensing. 30,31 During the synthesis of red-P, Hittorf and Thurn et al observed the formation of plate-like and fiber bundles of phosphorus crystals, namely, violet phosphorus (violet-P) and fibrous phosphorus (fibrous-P), respectively.…”