Efficient exfoliation of graphite in chloroform with a pyrene-containing hyperbranched polyethylene as stabilizer to render pyrene-functionalized high-quality graphene

Duan, Donghai; Ye, Huijian; Meng, Nan; Xu, Chenxi; Han, Bo; Chen, Yafei; Zhong, Ming; Xu, Lixin

doi:10.1016/j.carbon.2018.04.042

Cited by 32 publications

(37 citation statements)

References 69 publications

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“…Following the addition of a solvent to the intimately mixed graphite-cNDI, and before sonication, an opaque suspension was observed ( Figure 2b and 2c) an indication of the presence of exfoliated graphite . [9,22] When cNDIs were not used, no such dark dispersions were observed (Figure 2a). These results strongly suggest the existence π-donor-π-acceptor electrostatic interactions between the electron rich graphite and the electron deficient cNDIs in solid phase, leading to the disruption of the interlayer interactions, and hence the dispersion of graphite in the solvent.…”

Section: Resultsmentioning

confidence: 98%

“…Specifically, the readily available cNDIs 2,6‐dibromo‐NDI (DBNDI) and 2,3,6,7‐tetrabromo‐NDI (TBNDI) (Figure ). These highly electron deficient cNDI molecules serve a dual purpose: (i) to enhance their electrostatic interactions with the readily available π electrons of graphite, essential in initiating cleavage and peeling away of graphene units; and (ii) to favour adsorptions of cNDIs onto the electron‐dense graphene surface to improve the dispersibility and stability of resultant graphene dispersions by reducing re‐aggregation/re‐stacking through the electrostatic repulsion effect . Systematic studies on the differences of graphene exfoliation yields in chloroform and NMP using both DBNDI and TBNDI are done and correlated to solvent interactions and steric effects as a result of di‐ and tetra‐bromo core substitution of cNDIs.…”

Section: Introductionmentioning

confidence: 99%

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Molecular Design of Core Substituted Naphthalene Diimides for the Exfoliation of Graphite to Graphene in Chloroform

et al. 2019

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A significant challenge of liquid phase exfoliation (LPE) of graphite to yield graphene resides in the fact that most conventional solvents used are high boiling points and thus extremely difficult to eliminate, especially during processing of graphene into composites or films. Here, we advance the ability to produce high yield graphene in a low boiling point organic solvent, chloroform, using core‐substituted naphthalene diimides (cNDIs). Through the use of cNDIs it is possible to obtain high graphene concentrations of up to 0.13 mg/mL in chloroform. This yield represents a 69% improvement from graphene yields previously obtained in chloroform using unsubstituted NDIs. Characterisation of the products by UV‐Vis, X‐ray diffraction (XRD), Transmission electron microscopy (TEM), Raman spectroscopy and X‐ray photoelectron spectroscopy (XPS) support the use of cNDIs as an appropriate exfoliating agent in chloroform.

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Section: Resultsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Molecular Design of Core Substituted Naphthalene Diimides for the Exfoliation of Graphite to Graphene in Chloroform

et al. 2019

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“…While sonication or shear force serves to exfoliate graphite by overcoming the interlayered π–π stacking interactions, the stabilizers adsorb on the exfoliated graphene surface through noncovalent interactions. On one hand, this effectively prevents their aggregation/re‐stacking based on the sterical hindrance mechanism or electrostatic repulsion effect, thus promoting efficient graphite exfoliation even in some common solvents . On the other hand, this also can concurrently render functionalized graphene.…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, this also can concurrently render functionalized graphene. So far, a diverse range of stabilizers have been explored for liquid‐phase exfoliation of graphite, including surfactants, functional small molecules, nanoparticles, polymers, ionic liquid, natural resins, etc. Nevertheless, the exploration of the multifunctional stabilizers, which not only can effectively promote graphite exfoliation, but also can concurrently functionalize the exfoliated graphene, remains highly desirable.…”

Section: Introductionmentioning

confidence: 99%

“…In a recent work, they synthesized a star‐shaped HBPE copolymer and suggested that it can promote graphite exfoliation in water to render CO 2 ‐switchable graphene dispersions. In a recent research, we have synthesized a pyrene‐functionalized HBPE via binary copolymerization of ethylene and a pyrene‐containing monomer with the catalyst 1 , and found that it can effectively promote graphite exfoliation in chloroform to render pyrene‐functionalized graphene.…”

Section: Introductionmentioning

confidence: 99%

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Efficient Production of High‐Quality Polystyrene‐Functionalized Graphene via Graphite Exfoliation in Chloroform with a Heterobifunctional Hyperbranched Polyethylene as Stabilizer

Duan

Luo

et al. 2019

Macro Chemistry & Physics

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Efficient production of high‐quality, functionalized graphene is highly desirable for large‐scale applications of graphene. Herein, a route for producing high‐quality, polystyrene (PS)‐functionalized graphene is demonstrated via graphite exfoliation in chloroform with a heterobifunctional hyperbranched polyethylene, HBPE@Py@PS, as stabilizer. The HBPE@Py@PS, possessing a pyrene‐functionalized hyperbranched polyethylene backbone and multiple PS side chains, is synthesized by combining chain walking polymerization and atom transfer radical polymerization techniques. It is confirmed that the HBPE@Py@PS can effectively promote graphite exfoliation in chloroform under sonication to render stable dispersions of high‐quality graphene, with an exfoliation efficiency high as 15% and a monolayer proportion, 61%. Meanwhile, it can irreversibly adsorb on the exfoliated graphene surface based on the π–π stacking interactions, concurrently rendering PS‐functionalized graphene that is fluorescent and highly dispersible in chloroform, with a film conductivity reaching 1100 S m−1. The as‐produced graphene may find its applications as nanofiller for various PS‐based graphene nanocomposites.

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Graphene Nanoplatelet Exoskeleton on Polyurethane Foam to Produce Flame‐Retardant, Piezoresistive, and Electromagnetic Interference Shielding Surfaces

Weldemhret,

Lee,

M.N.

et al. 2023

Adv Materials Inter

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Polyurethane foam (PUF)’s porous structure, light weight, flexibility, and low‐cost properties make it useful in various cutting‐edge technologies. However, time‐consuming, costly, and complicated surface modification methods severely hinder its commercial applications. Herein, an ultrafast, simple, and cost‐effective surface modification method based on the evaporation of a low boiling point solvent to prepare a multifunctional graphene nanoplatelet (GNP)‐decorated PUF (GNP@PUF) is proposed. Due to the passive heat barrier of GNP sheets, the resulting sponge exhibits excellent flame retardancy by reducing the critical fire retardancy metrics, that is, peak heat release rate, total heat release, and total smoke release by 72%, 50%, and 81%, respectively. In addition, GNP@PUF can function as a piezoresistive sensor and electromagnetic interference (EMI)‐shielding material. As a piezoresistive sensor, it exhibits a wide‐compressive pressure (2.4–112 kPa)/strain (5–70%) range and ultra‐fast response/relaxation time (48/35 ms), wide‐stretching strain (5–100%) range, and it can detect minute human motions by being attached to different parts of the human body. Meanwhile, the composite foam displays good absorption‐dominant EMI shielding performance (≈38 dB), possibly due to conductive dissipation and multiple reflections/scattering of EM waves inside the 3D conductive graphene network. This study provides a simple coating technique for developing multifunctional lightweight foam materials.

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Efficient exfoliation of graphite in chloroform with a pyrene-containing hyperbranched polyethylene as stabilizer to render pyrene-functionalized high-quality graphene

Cited by 32 publications

References 69 publications

Molecular Design of Core Substituted Naphthalene Diimides for the Exfoliation of Graphite to Graphene in Chloroform

Molecular Design of Core Substituted Naphthalene Diimides for the Exfoliation of Graphite to Graphene in Chloroform

Efficient Production of High‐Quality Polystyrene‐Functionalized Graphene via Graphite Exfoliation in Chloroform with a Heterobifunctional Hyperbranched Polyethylene as Stabilizer

Graphene Nanoplatelet Exoskeleton on Polyurethane Foam to Produce Flame‐Retardant, Piezoresistive, and Electromagnetic Interference Shielding Surfaces

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