General Approach to Individually Dispersed, Highly Soluble, and Conductive Graphene Nanosheets Functionalized by Nitrene Chemistry

Abstract

A unified approach to covalently functionalize graphene nanosheets based on nitrene chemistry is reported. This strategy is simple and efficient, allowing various functional moieties (e.g., hydroxyl, carboxyl, amino, bromine, long alkyl chain, etc.) and polymers (e.g., poly(ethylene glycol), polystryene) to covalently and stably anchor on graphene to produce single-layer functionalized graphene from graphene oxide in a one-step reaction. The structure and morphology of nanosheets are characterized using microscopy (AFM, SEM, TEM), spectroscopy (FTIR, XPS, Raman), thermal gravimetric analysis (TGA), and X-ray diffraction (XRD) measurements. The resulting functionalized graphene nanosheets are electrically conductive, readily dispersible in solvents and easily processable, making them promising candidates for further modification and applications such as nanohybrids, and polymer composites, etc. The presented work provides a general methodology to prepare individually dispersed graphene nanosheets with various functionalizations and properties, paving the way for the synthesis and applications of functionalized graphene materials.

Covalently Functionalized Hexagonal Boron Nitride Nanosheets by Nitrene Addition

“…The significant loss in intensity and shift of the C=O vibration from 1718 cm -1 in the starting methoxyphenyl azido formate to 1734 cm -1 in the bound molecule is consistent with covalent bonding. 10,11 Thus, the presence of the molecular signature of the MPC molecule along with additional bonding features strongly supports the assertion of covalent nitrene addition to the h-BN lattice. H-NMR was also used to characterize the MPCfunctionalized h-BN.…”

“…In contrast, a number of groups have described the covalent modification of graphene. 10,11 This is important as such modification can impart chemical functionality and facilitate integration of the exfoliated material within polymer systems. Due to the high intrinsic strength of h-BN, 12 such systems could be the basis of future high performance composites.…”

“…Previously, nitrene addition has been used to covalently functionalize graphene and CNTs via the formation of aziridine ring species. 10,13 Even though BN allotropes are known to exhibit excellent chemical stability in strongly acidic and basic conditions, 14 it might be expected that the generation of a highly reactive nitrene species in the presence of exfoliated h-BN could result in covalent functionalization of the h-BN sheet.…”

Oxygen Radical Functionalization of Boron Nitride Nanosheets

“…[8][9][10] It is noted that multiple reports have described covalent chemical modification of graphene with organic moieties to impart chemical functionality and hence facilitate integration within polymer systems. [11][12][13] In recent years it has become clear that the ability to chemically functionalize graphene to graphene oxide has massively expanded its potential for applications. 4,14 It is also clear that having an alternative isostructural material which is white/transparent, insulating, chemically stable, mechanically strong, thermal conductive, and which may be isolated as exfoliated atomic sheets, may hold many advantages over the carbon analogue for certain applications such as optical components, surface coatings and transparent composites.…”

Graphene-templated approach to ultrathin silica nanosheets

“…Conditions: (1) In DMF, at 65°C for 24-36 h; (2) 25% aqueous ammonia solution at room temperature for 24 h; (3) pyrolysis in air at 700°C for 10 h. the visualization of graphene and its hybrid structures [5, [22][23][24][25]. Figure 1(a) shows the AFM images of Sample 1 at different synthesis stages.…”