Michael Shtein | Ben Gurion University of the Negev (original) (raw)

Papers by Michael Shtein

The energy supplied to the solution per graphite mass by sonication and shear mixing was calculat... more The energy supplied to the solution per graphite mass by sonication and shear mixing was calculated as described below to enhance comparison between top-down methods. The total input energy was measured in an isolated vial, by measuring the dispersion temperature (T) every 20 seconds according to Equation S1: 1-2 (S1) = • • ∆ = 41.86 • ∆ [ ] where M is the solution mass (for water-0.01kg, the graphite mass is negligible); Cp, the heat capacity of water (4186 J•(kg•)-1), and ∆ is the measured temperature difference every 20 seconds.

Nanotechnology in Construction, 2015

Loading a matrix with nano-sized particles such as nanotubes (carbon or tungsten di-sulfi de) is ... more Loading a matrix with nano-sized particles such as nanotubes (carbon or tungsten di-sulfi de) is expected to improve the mechanical properties of composite materials better than traditional (macroscopic) fi llers due to extra-ordinary mechanical properties accompanied by high surface area. One of the major challenges towards achieving this goal is an effective dispersion of the as-produced aggregated nanotubes. In this work we demonstrate a novel dispersion method, facilitating the integration of individual nanotubes in cement paste matrix. We demonstrate the effectiveness of our nanotubes dispersion method by enhancing both fl exural strength and compressive strength of cement paste using carbon and tungsten di-sulfi de nanotubes. Finally, a comprehensive fractography study indicates that both types of nanotubes fail via pull-out mechanism with an intermediate state of bridging mechanism.

The extraordinary mechanical properties of graphene prompt its incorporation into a wide range of... more The extraordinary mechanical properties of graphene prompt its incorporation into a wide range of polymeric nanocomposite materials (NCMs). However, similar to other nanomaterials (NMs), the reinforcement efficiency of graphene and its derivatives is hindered by their agglomeration and poor compatibility with the polymer matrix. In this paper, edge-functionalized graphene nanoribbons (EF-GNR) are incorporated in brittle epoxy polymer matrix. The functionalization process by polyvinylamine (PVAM) chains occurs only at the edges, preserving the in-plane sp 2 of the graphene; thereby the PVAM EF-GNRs are both compatible and strong. The produced NCMs exhibit a wide range of enhanced mechanical properties including fracture toughness, flexural strength and shear strength at low EF-GNR loading (0.15 wt%). The effect of the edge functionalization is indeed critical, demonstrating superior mechanical properties by the EF-GNR loaded NCMs compared to pristine-GNR loaded composites. Finally, a comparative overview of various carbon NM-loaded NCMs indicates that EF-GNR possess high reinforcement efficiency (enhancement % per NM loading %) making it an attractive filler for polymer systems.

Thermal management has become a critical aspect in next-generation miniaturized electronic device... more Thermal management has become a critical aspect in next-generation miniaturized electronic devices. Efficient heat dissipation reduces their operating temperatures and insures optimal performance, service life, and efficacy. Shielding against shocks, vibrations, and moisture is also imperative when the electronic circuits are located outdoors. Potting (or encapsulating) them in polymer-based composites with enhanced thermal conductivity (TC) may provide a solution for both thermal management and shielding challenges. In the current study, graphene is employed as a filler to fabricate composites with isotropic ultrahigh TC (>12 W m −1 K −1) and good mechanical properties (>30 MPa flexural and compressive strength). To avoid short-circuiting the electronic assemblies, a dispersion of secondary ceramic-based filler reduces the electrical conductivity and synergistically enhances the TC of composites. When utilized as potting materials, these novel hybrid composites effectively dissipate the heat from electronic devices; their operating temperatures decrease from 110 to 37 °C, and their effective thermal resistances are drastically reduced, by up to 90%. The simple filler dispersion method and the precise manipulation of the composite transport properties via hybrid filling offer a universal approach to the large-scale production of novel materials for thermal management and other applications.

G raphene quantum dots (GQDs), sheets of graphene with less than 10 layers and lateral dimensions... more G raphene quantum dots (GQDs), sheets of graphene with less than 10 layers and lateral dimensions smaller than 100 nm, possess strong quantum confinement and edge effects. 1,2 Thus, they possess unique physical properties such as strong wavelength-dependent down-and up-conversion photoluminescence (PL), 3−7 which can be tailored for specific applications by controlling their size, 8 shape, defects, and functionality. 9

Tungsten di-Sulfide NanoTubes (WS 2 NTs) enhance the cement flexural strength by 74%. We develope... more Tungsten di-Sulfide NanoTubes (WS 2 NTs) enhance the cement flexural strength by 74%. We developed a method to disperse WS 2 NT individually in cement paste. Optimal enhancement occurs at extremely low WS 2 NT concentration (0.15 wt%). WS 2 NTs inhibit crack propagation by bridging, and fail via pullout mechanism. g r a p h i c a l a b s t r a c t a b s t r a c t Nanotubes are considered as promising nano-reinforcement in cement-based materials. The main challenge towards achieving a significant enhancement in cement properties is an effective dispersion of the agglomerated nanotubes. In this paper, we demonstrate a novel dispersion method of Tungsten di-Sulfide NanoTubes (WS 2 NTs) that results in substantial flexural and compressive strength enhancements at optimal nanotube concentration as low as 0.15 wt%. The reinforcement by WS 2 NTs remains significant after a variety of curing processes, suggesting a genuine nanoscale reinforcing effect. Finally, by employing a comprehensive fractography we found that the WS 2 NTs inhibit crack propagation by bridging with a pullout failure mechanism.

The rapidly increasing device densities in electronics dictate the need for efficient thermal man... more The rapidly increasing device densities in electronics dictate the need for efficient thermal management. If successfully exploited, graphene, which possesses extraordinary thermal properties, can be commercially utilized in polymer composites with ultrahigh thermal conductivity (TC). The total potential of graphene to enhance TC, however, is restricted by the large interfacial thermal resistance between the polymer mediated graphene boundaries. We report a facile and scalable dispersion of commercially available graphene nanoplatelets (GnPs) in a polymer matrix, which formed composite with an ultrahigh TC of 12.4 W/m K (vs 0.2 W/m K for neat polymer). This ultrahigh TC was achieved by applying high compression forces during the dispersion that resulted in the closure of gaps between adjacent GnPs with large lateral dimensions and low defect densities. We also found strong evidence for the existence of a thermal percolation threshold. Finally, the addition of electrically insulating boron-nitride nanoparticles to the thermally conductive GnP-polymer composite significantly reduces its electrical conductivity (to avoid short circuit) and synergistically increases the TC. The efficient dispersion of commercially available GnPs in polymer matrix provides the ideal framework for substantial progress toward the large-scale production and commercialization of GnP-based thermally conductive composites.

The Journal of Physical Chemistry C, 2014

Noncovalent dispersion of carbon nanotubes is essential to most applications but still poorly und... more Noncovalent dispersion of carbon nanotubes is essential to most applications but still poorly understood at the molecular level. The interaction of the dispersing molecule with the nanotube, wrapping or nonwrapping, still awaits consensus. Herein, we have studied by 1 H NMR diffusometry some features of molecular dynamics in the system of carbon nanotubes dispersed by triblock copolymer Pluronics F127 in water. The diffusional decays obtained at different diffusion times, Δ, are not single-exponential and have a complex Δdependent profile, ultimately implying that the polymer is observed in two states: free (in unimeric form) and nanotubebound. Fitting a two-site exchange model to the data indicates that at any instant, only a small fraction of polymers are adsorbed on the nanotubes, with polydisperse residence times in the range of 100−400 ms. Most significantly, we further provide an estimate of D = (3−8) × 10 −12 m 2 s −1 for the coefficient of lateral diffusion of the polymer along the nanotube surface, which is an order of magnitude slower than the corresponding self-diffusion coefficient in water. The emerging picture is that of a nonwrapping mode for the polymer−nanotube interaction.

The Journal of Physical Chemistry B, 2012

The binding of block copolymer Pluronic F-127 in aqueous dispersions of single-(SWCNT) and multiw... more The binding of block copolymer Pluronic F-127 in aqueous dispersions of single-(SWCNT) and multiwalled (MWCNT) carbon nanotubes has been studied by pulsed-fieldgradient (PFG) 1 H NMR spectroscopy. We show that a major fraction of polymers exist as a free species while a minor fraction is bound to the carbon nanotubes (CNT). The polymers exchange between these two states with residence times on the nanotube surface of 24 ± 5 ms for SWCNT and of 54 ± 11 ms for MWCNT. The CNT concentration in the solution was determined by improved thermal gravimetric analysis (TGA) indicating that the concentration of SWCNT dispersed by F-127 was significantly higher than that for MWCNT. For SWCNT, the area per adsorbed Pluronic F-127 molecule is estimated to be about 40 nm 2 .

The Analyst, 2013

Upon dispersant-assisted exfoliation, pristine carbon nanotubes (CNTs) are divided between the su... more Upon dispersant-assisted exfoliation, pristine carbon nanotubes (CNTs) are divided between the supernatant and precipitate, which makes the determination of dispersant concentration a challenging task. We have developed a thermogravimetric-spectroscopy-based approach to accurately determine the dispersant-assisted CNT (or nanoparticles, in general) concentration in dispersion. A thermogravimetric analysis of the filtered and washed precipitate, that is usually discarded after centrifugation, is used here to accurately calculate the CNT mass in the precipitate and (through mass-balance) its mass in the supernatant. Once the true CNT concentration has been determined, a conventional spectroscopy-based concentration calibration plot is constructed for simple and swift use in further concentration measurements. Such true concentration analysis is crucial for studying the concentration-property relationship.

Physical Chemistry Chemical Physics, 2013

Dispersing graphite into few-layers graphene sheets (GS) in water is very appealing as an environ... more Dispersing graphite into few-layers graphene sheets (GS) in water is very appealing as an environmental-friendly, low-cost, low-energy method of obtaining graphene. Very high GS concentrations in water (0.7 mg mL(-1)) were obtained by optimizing the nature of dispersant and the type of ultra-sonic generator. We find that a multi-step sonication procedure involving both tip and bath sources considerably enhances the yield of exfoliated GS. Raman and transmission electron microscopy indicate few-layers graphene patches with typical size of ∼0.65 μm in one dimension and ∼0.35 μm in the other. These were further employed in combination with water-dispersed CNTs to fabricate conductive transparent electrodes for a molecularly-controlled solar-cell with an open-circuit voltage of 0.53 V.

Composites Science and Technology, 2013

ABSTRACT The utilization of highly branched polymer (e.g., epoxy resins) in engineering applicati... more ABSTRACT The utilization of highly branched polymer (e.g., epoxy resins) in engineering applications is often limited by their brittle nature (low fracture toughness). Loading the polymer matrix by fillers such as individual nanotubes is a promising alternative to enhance fracture toughness without compromising other mechanical properties. However, to fully understand the nanotubes toughening role and correctly characterize the nanocomposite failure mechanisms, a complete exfoliation of the nanotubes aggregates into individual nanotubes is essential. In this work, we embed only individual nanotubes in the polymer matrix using a novel dispersion method. The individual nanotube concentration in the composite is accurately determined. We achieve a record fracture toughness enhancement and, for the first time, demonstrate a coherent quantitative correlation between the fracture toughness and the surface roughness. Finally, comprehensive statistical investigation of the nanotube failure mechanisms shows that carbon nanotubes fail via fracture mechanism, while tungsten di-sulfide nanotubes via pullout mechanism. The failure mechanism could be predicted by the slope of the surface roughness vs. fracture toughness curve.

Analytical Chemistry, 2015

The rapid increase in graphene-based applications has been accompanied by novel top-down manufact... more The rapid increase in graphene-based applications has been accompanied by novel top-down manufacturing methods for graphene and its derivatives (e.g., graphene nanoplatelets (GnPs)). The characterization of the bulk properties of these materials by imaging and surface techniques (e.g., electron microscopy and Raman spectroscopy) is only possible through laborious and time-consuming statistical analysis, which precludes simple and efficient quality control during GnP production. We report that thermogravimetry (TG) may be utilized, beyond its conventional applications (e.g., quantification of impurities or surfactants, or labile functional groups) to characterize bulk GnP properties. We characterize the structural parameters of GnP (i.e., defect density, mean lateral dimension, and polydispersity) by imaging and surface techniques, on one hand, and by a systematic TG, on the other. The combined data demonstrate that the combustion temperature of commercially available and laboratory-prepared GnPs is correlated with their mean lateral dimension and defect density, while the combustion temperature range is proportional to their polydispersity index. Mapping all these parameters allows one to evaluate the GnPs' structure following a simple thermogravimetric experiment (without necessitating further statistical analysis). Finally, TG is also used to detect and quantify different GnP constituents in powder and to conduct rapid quality-control tests during GnP production.

The energy supplied to the solution per graphite mass by sonication and shear mixing was calculat... more The energy supplied to the solution per graphite mass by sonication and shear mixing was calculated as described below to enhance comparison between top-down methods. The total input energy was measured in an isolated vial, by measuring the dispersion temperature (T) every 20 seconds according to Equation S1: 1-2 (S1) = • • ∆ = 41.86 • ∆ [ ] where M is the solution mass (for water-0.01kg, the graphite mass is negligible); Cp, the heat capacity of water (4186 J•(kg•)-1), and ∆ is the measured temperature difference every 20 seconds.

Nanotechnology in Construction, 2015

Loading a matrix with nano-sized particles such as nanotubes (carbon or tungsten di-sulfi de) is ... more Loading a matrix with nano-sized particles such as nanotubes (carbon or tungsten di-sulfi de) is expected to improve the mechanical properties of composite materials better than traditional (macroscopic) fi llers due to extra-ordinary mechanical properties accompanied by high surface area. One of the major challenges towards achieving this goal is an effective dispersion of the as-produced aggregated nanotubes. In this work we demonstrate a novel dispersion method, facilitating the integration of individual nanotubes in cement paste matrix. We demonstrate the effectiveness of our nanotubes dispersion method by enhancing both fl exural strength and compressive strength of cement paste using carbon and tungsten di-sulfi de nanotubes. Finally, a comprehensive fractography study indicates that both types of nanotubes fail via pull-out mechanism with an intermediate state of bridging mechanism.

The extraordinary mechanical properties of graphene prompt its incorporation into a wide range of... more The extraordinary mechanical properties of graphene prompt its incorporation into a wide range of polymeric nanocomposite materials (NCMs). However, similar to other nanomaterials (NMs), the reinforcement efficiency of graphene and its derivatives is hindered by their agglomeration and poor compatibility with the polymer matrix. In this paper, edge-functionalized graphene nanoribbons (EF-GNR) are incorporated in brittle epoxy polymer matrix. The functionalization process by polyvinylamine (PVAM) chains occurs only at the edges, preserving the in-plane sp 2 of the graphene; thereby the PVAM EF-GNRs are both compatible and strong. The produced NCMs exhibit a wide range of enhanced mechanical properties including fracture toughness, flexural strength and shear strength at low EF-GNR loading (0.15 wt%). The effect of the edge functionalization is indeed critical, demonstrating superior mechanical properties by the EF-GNR loaded NCMs compared to pristine-GNR loaded composites. Finally, a comparative overview of various carbon NM-loaded NCMs indicates that EF-GNR possess high reinforcement efficiency (enhancement % per NM loading %) making it an attractive filler for polymer systems.

Thermal management has become a critical aspect in next-generation miniaturized electronic device... more Thermal management has become a critical aspect in next-generation miniaturized electronic devices. Efficient heat dissipation reduces their operating temperatures and insures optimal performance, service life, and efficacy. Shielding against shocks, vibrations, and moisture is also imperative when the electronic circuits are located outdoors. Potting (or encapsulating) them in polymer-based composites with enhanced thermal conductivity (TC) may provide a solution for both thermal management and shielding challenges. In the current study, graphene is employed as a filler to fabricate composites with isotropic ultrahigh TC (>12 W m −1 K −1) and good mechanical properties (>30 MPa flexural and compressive strength). To avoid short-circuiting the electronic assemblies, a dispersion of secondary ceramic-based filler reduces the electrical conductivity and synergistically enhances the TC of composites. When utilized as potting materials, these novel hybrid composites effectively dissipate the heat from electronic devices; their operating temperatures decrease from 110 to 37 °C, and their effective thermal resistances are drastically reduced, by up to 90%. The simple filler dispersion method and the precise manipulation of the composite transport properties via hybrid filling offer a universal approach to the large-scale production of novel materials for thermal management and other applications.

G raphene quantum dots (GQDs), sheets of graphene with less than 10 layers and lateral dimensions... more G raphene quantum dots (GQDs), sheets of graphene with less than 10 layers and lateral dimensions smaller than 100 nm, possess strong quantum confinement and edge effects. 1,2 Thus, they possess unique physical properties such as strong wavelength-dependent down-and up-conversion photoluminescence (PL), 3−7 which can be tailored for specific applications by controlling their size, 8 shape, defects, and functionality. 9

Tungsten di-Sulfide NanoTubes (WS 2 NTs) enhance the cement flexural strength by 74%. We develope... more Tungsten di-Sulfide NanoTubes (WS 2 NTs) enhance the cement flexural strength by 74%. We developed a method to disperse WS 2 NT individually in cement paste. Optimal enhancement occurs at extremely low WS 2 NT concentration (0.15 wt%). WS 2 NTs inhibit crack propagation by bridging, and fail via pullout mechanism. g r a p h i c a l a b s t r a c t a b s t r a c t Nanotubes are considered as promising nano-reinforcement in cement-based materials. The main challenge towards achieving a significant enhancement in cement properties is an effective dispersion of the agglomerated nanotubes. In this paper, we demonstrate a novel dispersion method of Tungsten di-Sulfide NanoTubes (WS 2 NTs) that results in substantial flexural and compressive strength enhancements at optimal nanotube concentration as low as 0.15 wt%. The reinforcement by WS 2 NTs remains significant after a variety of curing processes, suggesting a genuine nanoscale reinforcing effect. Finally, by employing a comprehensive fractography we found that the WS 2 NTs inhibit crack propagation by bridging with a pullout failure mechanism.

The rapidly increasing device densities in electronics dictate the need for efficient thermal man... more The rapidly increasing device densities in electronics dictate the need for efficient thermal management. If successfully exploited, graphene, which possesses extraordinary thermal properties, can be commercially utilized in polymer composites with ultrahigh thermal conductivity (TC). The total potential of graphene to enhance TC, however, is restricted by the large interfacial thermal resistance between the polymer mediated graphene boundaries. We report a facile and scalable dispersion of commercially available graphene nanoplatelets (GnPs) in a polymer matrix, which formed composite with an ultrahigh TC of 12.4 W/m K (vs 0.2 W/m K for neat polymer). This ultrahigh TC was achieved by applying high compression forces during the dispersion that resulted in the closure of gaps between adjacent GnPs with large lateral dimensions and low defect densities. We also found strong evidence for the existence of a thermal percolation threshold. Finally, the addition of electrically insulating boron-nitride nanoparticles to the thermally conductive GnP-polymer composite significantly reduces its electrical conductivity (to avoid short circuit) and synergistically increases the TC. The efficient dispersion of commercially available GnPs in polymer matrix provides the ideal framework for substantial progress toward the large-scale production and commercialization of GnP-based thermally conductive composites.

The Journal of Physical Chemistry C, 2014

Noncovalent dispersion of carbon nanotubes is essential to most applications but still poorly und... more Noncovalent dispersion of carbon nanotubes is essential to most applications but still poorly understood at the molecular level. The interaction of the dispersing molecule with the nanotube, wrapping or nonwrapping, still awaits consensus. Herein, we have studied by 1 H NMR diffusometry some features of molecular dynamics in the system of carbon nanotubes dispersed by triblock copolymer Pluronics F127 in water. The diffusional decays obtained at different diffusion times, Δ, are not single-exponential and have a complex Δdependent profile, ultimately implying that the polymer is observed in two states: free (in unimeric form) and nanotubebound. Fitting a two-site exchange model to the data indicates that at any instant, only a small fraction of polymers are adsorbed on the nanotubes, with polydisperse residence times in the range of 100−400 ms. Most significantly, we further provide an estimate of D = (3−8) × 10 −12 m 2 s −1 for the coefficient of lateral diffusion of the polymer along the nanotube surface, which is an order of magnitude slower than the corresponding self-diffusion coefficient in water. The emerging picture is that of a nonwrapping mode for the polymer−nanotube interaction.

The Journal of Physical Chemistry B, 2012

The binding of block copolymer Pluronic F-127 in aqueous dispersions of single-(SWCNT) and multiw... more The binding of block copolymer Pluronic F-127 in aqueous dispersions of single-(SWCNT) and multiwalled (MWCNT) carbon nanotubes has been studied by pulsed-fieldgradient (PFG) 1 H NMR spectroscopy. We show that a major fraction of polymers exist as a free species while a minor fraction is bound to the carbon nanotubes (CNT). The polymers exchange between these two states with residence times on the nanotube surface of 24 ± 5 ms for SWCNT and of 54 ± 11 ms for MWCNT. The CNT concentration in the solution was determined by improved thermal gravimetric analysis (TGA) indicating that the concentration of SWCNT dispersed by F-127 was significantly higher than that for MWCNT. For SWCNT, the area per adsorbed Pluronic F-127 molecule is estimated to be about 40 nm 2 .

The Analyst, 2013

Upon dispersant-assisted exfoliation, pristine carbon nanotubes (CNTs) are divided between the su... more Upon dispersant-assisted exfoliation, pristine carbon nanotubes (CNTs) are divided between the supernatant and precipitate, which makes the determination of dispersant concentration a challenging task. We have developed a thermogravimetric-spectroscopy-based approach to accurately determine the dispersant-assisted CNT (or nanoparticles, in general) concentration in dispersion. A thermogravimetric analysis of the filtered and washed precipitate, that is usually discarded after centrifugation, is used here to accurately calculate the CNT mass in the precipitate and (through mass-balance) its mass in the supernatant. Once the true CNT concentration has been determined, a conventional spectroscopy-based concentration calibration plot is constructed for simple and swift use in further concentration measurements. Such true concentration analysis is crucial for studying the concentration-property relationship.

Physical Chemistry Chemical Physics, 2013

Dispersing graphite into few-layers graphene sheets (GS) in water is very appealing as an environ... more Dispersing graphite into few-layers graphene sheets (GS) in water is very appealing as an environmental-friendly, low-cost, low-energy method of obtaining graphene. Very high GS concentrations in water (0.7 mg mL(-1)) were obtained by optimizing the nature of dispersant and the type of ultra-sonic generator. We find that a multi-step sonication procedure involving both tip and bath sources considerably enhances the yield of exfoliated GS. Raman and transmission electron microscopy indicate few-layers graphene patches with typical size of ∼0.65 μm in one dimension and ∼0.35 μm in the other. These were further employed in combination with water-dispersed CNTs to fabricate conductive transparent electrodes for a molecularly-controlled solar-cell with an open-circuit voltage of 0.53 V.

Composites Science and Technology, 2013

ABSTRACT The utilization of highly branched polymer (e.g., epoxy resins) in engineering applicati... more ABSTRACT The utilization of highly branched polymer (e.g., epoxy resins) in engineering applications is often limited by their brittle nature (low fracture toughness). Loading the polymer matrix by fillers such as individual nanotubes is a promising alternative to enhance fracture toughness without compromising other mechanical properties. However, to fully understand the nanotubes toughening role and correctly characterize the nanocomposite failure mechanisms, a complete exfoliation of the nanotubes aggregates into individual nanotubes is essential. In this work, we embed only individual nanotubes in the polymer matrix using a novel dispersion method. The individual nanotube concentration in the composite is accurately determined. We achieve a record fracture toughness enhancement and, for the first time, demonstrate a coherent quantitative correlation between the fracture toughness and the surface roughness. Finally, comprehensive statistical investigation of the nanotube failure mechanisms shows that carbon nanotubes fail via fracture mechanism, while tungsten di-sulfide nanotubes via pullout mechanism. The failure mechanism could be predicted by the slope of the surface roughness vs. fracture toughness curve.

Analytical Chemistry, 2015

The rapid increase in graphene-based applications has been accompanied by novel top-down manufact... more The rapid increase in graphene-based applications has been accompanied by novel top-down manufacturing methods for graphene and its derivatives (e.g., graphene nanoplatelets (GnPs)). The characterization of the bulk properties of these materials by imaging and surface techniques (e.g., electron microscopy and Raman spectroscopy) is only possible through laborious and time-consuming statistical analysis, which precludes simple and efficient quality control during GnP production. We report that thermogravimetry (TG) may be utilized, beyond its conventional applications (e.g., quantification of impurities or surfactants, or labile functional groups) to characterize bulk GnP properties. We characterize the structural parameters of GnP (i.e., defect density, mean lateral dimension, and polydispersity) by imaging and surface techniques, on one hand, and by a systematic TG, on the other. The combined data demonstrate that the combustion temperature of commercially available and laboratory-prepared GnPs is correlated with their mean lateral dimension and defect density, while the combustion temperature range is proportional to their polydispersity index. Mapping all these parameters allows one to evaluate the GnPs' structure following a simple thermogravimetric experiment (without necessitating further statistical analysis). Finally, TG is also used to detect and quantify different GnP constituents in powder and to conduct rapid quality-control tests during GnP production.