Edge‐Hydroxylated Boron Nitride Nanosheets as an Effective Additive to Improve the Thermal Response of Hydrogels

Feng, Xiao; Naficy, Sina; Casillas, Gilberto; Khan, Majharul Haque; Katkus, Tomas; Jiang, Lei; Liu, Huan; Li, Huijun; Huang, Zhenguo

doi:10.1002/adma.201502803

Cited by 250 publications

(235 citation statements)

References 47 publications

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“…These phenomena indicate that the exfoliation appears, corresponding to the XRD characterization results. As shown in Figure e,f, the OH‐BNNSs exhibit more rough surfaces and edges, and the morphologies are in contrast to pristine h‐BN and as‐exfoliated h‐BNNSs . After the surface modification, APTS‐BNNSs show rough and cross‐linking between layers (Figure g,h), which may be due to the formation of chemical bond between the hydroxyl groups on the surface of as‐exfoliated h‐BNNSs and the hydrolyzed APTS molecules.…”

Section: Resultsmentioning

confidence: 95%

Covalent Functionalized Boron Nitride Nanosheets as Efficient Lubricant Oil Additives

Wang

Han

et al. 2019

Adv Materials Inter

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Hexagonal boron nitride nanosheets (h‐BNNSs) are obtained by a chemical exfoliation method from bulk h‐BN powders. The surface of h‐BNNSs is functionalized with 3‐aminopropyltriethoxysilane (APTS). Further, the amino functional groups on the surface of APTS‐modified h‐BNNSs (APTS‐BNNSs) are reacted with 4‐carboxyphenylboronic acid (CPBA) to obtain the covalently linked CPBA‐BNNSs. The morphology and structure of h‐BNNSs, APTS‐BNNSs, and CPBA‐BNNSs are comprehensively discussed. Of all the above four additives, the CPBA‐BNNSs can most outstandingly improve friction‐reducing and antiwear capacities of 150N base oil. The CPBA‐BNNSs possess excellent dispersion stability in base oil due to the phenylboronic acid groups on the surface of h‐BNNSs. Only 0.075 wt% CPBA‐BNNSs is added into the base oil, the coefficient of friction is decreased by 32.3%, and the wear scar diameter and mean wear volume of the rubbing surface are reduced by 42.9% and 88.4%. The analysis of the worn scar surface demonstrates that CPBA‐BNNSs can form a protective tribofilm containing boron and nitrogen elements on the rubbing surfaces, thereby decreasing the friction and protecting the surfaces from wear. Thus, the CPBA‐BNNSs may be recommended as a potential lubricant additive in practical applications.

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Section: Resultsmentioning

confidence: 95%

Covalent Functionalized Boron Nitride Nanosheets as Efficient Lubricant Oil Additives

Wang

Han

et al. 2019

Adv Materials Inter

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“…When it comes to hydrogels samples, which is unique for their intrinsic half-liquid and half-solid characteristics, it is challenging and special consideration is needed. For example, laser-flash method is a simple one and has been reported to measure thermal conductivity of hydrogel nanocomposites with BN nanosheets [19]. But laser-flash method usually requires opaque samples and thus is not appropriate for the completely transparent samples.…”

Section: Resultsmentioning

confidence: 99%

“…The hydrogel nanocomposites incorporated with boron nitride (BN) nanopalettes shows an enhanced thermo-responsive time in poly(N -isopropyl-acrylamide) (PNIPAm)/BN hydrogels or a better performance as thermal interface materials in poly(acrylic acid) (PAA)/BN hydrogels [19,20]. These investigations pay attention to the role of nanofillers, a compelling experimental investigation of intrinsic thermal conductivity of hydrogels itself has not yet been well explored.…”

Section: Introductionmentioning

confidence: 99%

Thermal Conduction Behaviors of PAAm Hydrogels

Tang¹,

Peng²,

Guo³

et al. 2017

Preprint

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Abstract:As the interface between human and machine becomes blurred, hydrogel incorporated electronics and devices have emerged to be a new class of flexible/stretchable electronic and ionic devices due to their extraordinary properties, such as soft, mechanically robust and biocompatible. However, heat dissipation in these devices could be a critical issue and remains unexplored. Here, we report the experimental measurements and equilibrium molecular dynamics simulations of thermal conduction in polyacrylamide (PAAm) hydrogels. The thermal conductivity of PAAm hydrogels can be modulated by both the crosslinking density and water content in hydrogels. The crosslinking density dependent thermal conductivity in hydrogels varies from 0.33 to 0.51 Wm -1 K -1 , giving a 54% enhancement. We attribute the crosslinking effect to the competition between the increased conduction pathways and the enhanced phonon scattering effect. Moreover ， water content can act as filler in polymers which lead to nearly 40% enhancement in thermal conductivity in PAAm hydrogels with water content vary from 23 to 88 wt%. Furthermore，we find the thermal conductivity of PAAm hydrogel is insensitive to temperature in the range of 25 o C -40 o C. Our study offers fundamental understanding of thermal transport in soft materials and provides design guidance for hydrogel-based devices.

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“…9 Hydroxylation, as a type of chemical functionalization, is defined as the attachment of hydroxyl groups on the surface and edges of h-BN via covalent bonds, mainly to improve their dispersion in water and create more active reaction sites. [9][10][11] Limited studies have concentrated on the hydroxylated hexagonal boron nitride nanosheets (OH-BNNS), and the existing few are more concerned with the functionalization process [12][13][14] and electrical properties 15,16 rather than the mechanical properties of OH-BNNS. Chemical functionalization is usually held responsible for degradation in the engineering properties of graphene oxide (GO); a phenomenon dissected in previous studies 17 and is contributed to the breaking of perfect sp 2 hybridized carbon by hydroxyl groups and forming sp 3 hybridization instead.…”

Section: Introductionmentioning

confidence: 99%

Mechanical and electromechanical properties of functionalized hexagonal boron nitride nanosheet: A density functional theory study

Hosseini

Zakertabrizi

Korayem

et al. 2018

The Journal of Chemical Physics

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Hydroxylation as a technique is mainly used to alter the chemical characteristics of hexagonal boron nitride (h-BN), affecting physical features as well as mechanical and electromechanical properties in the process, the extent of which remains unknown. In this study, effects of functionalization on the physical, mechanical, and electromechanical properties of h-BN, including the interlayer distance, Young's modulus, intrinsic strength, and bandgaps were investigated based on density functional theory. It was found that functionalized layers of h-BN have an average distance of about 5.48 Å. Analyzing mechanical properties of h-BN revealed great dependence on the degree of functionalization. For the amorphous hydroxylated hexagonal boron nitride nanosheets (OH-BNNS), the Young's modulus moves from 436 to 284 GPa as the coverage of -OH increases. The corresponding variations in the Young's modulus of the ordered OH-BNNS with analogous coverage are bigger at 460-290 GPa. The observed intrinsic strength suggested that mechanical properties are promising even after functionalization. Moreover, the resulted bandgap reduction drastically enhanced the electrical conductivity of this structure under imposed strains. The results from this work pave the way for future endeavors in h-BN nanocomposites research.

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Edge‐Hydroxylated Boron Nitride Nanosheets as an Effective Additive to Improve the Thermal Response of Hydrogels

Abstract: . (2015). Edge-hydroxylated boron nitride nanosheets as an effective additive to improve the thermal response of hydrogels. Advanced Materials, 27 (44), 7196-7203.

Cited by 250 publications

References 47 publications

Covalent Functionalized Boron Nitride Nanosheets as Efficient Lubricant Oil Additives

Covalent Functionalized Boron Nitride Nanosheets as Efficient Lubricant Oil Additives

Thermal Conduction Behaviors of PAAm Hydrogels

Mechanical and electromechanical properties of functionalized hexagonal boron nitride nanosheet: A density functional theory study

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