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Kavitha CM, Eshwarappa KM, Shetty SJ, Gurumurthy SC, Surabhi S, Niranjana Prabhu T, Jeong JR, Morales DV. Modification of thermal and electrical characteristics of hybrid polymer nanocomposites through gamma irradiation for advanced applications. DISCOVER NANO 2024; 19:34. [PMID: 38386138 PMCID: PMC10884377 DOI: 10.1186/s11671-024-03972-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 02/08/2024] [Indexed: 02/23/2024]
Abstract
In this article, we present a straightforward in-situ approach for producing Ag NPs incorporated in graphene oxide (GO) blended with glutaraldehyde (GA) cross-linked polyvinyl alcohol (PVA) matrix. Samples are γ-irradiated by doses of 2, 5, and 10 kGy and in comparison with the pristine films, the thermal conductivity ('k') and effusivity are measured. 'k' decreases with irradiation doses up to 5 kGy and further increase in the dosage results increase in 'k'. We performed FDTD modeling to verify the effect of polarization and periodicity on the absorptivity and emissivity spectra that are correlated to the 'k' and effusivity, empirically. Hence, we can confess that the structural properties of the prepared hybrid nanocomposite are manipulated by γ-irradiation. This attests that the PVA/GO-Ag/GA nanocomposite is radiation-sensitive and could be employed for thermal management systems. Moreover, their strong electrical insulation, as the measured dc conductivity of the γ-irradiated samples is found to be in the range of 2.66 × 10-8-4.319 × 10-7 Sm-1, which is below the percolation threshold of 1.0 × 10-6 Sm-1, demonstrates that they are excellent candidates for the use of thermal management materials. The low 'k' values allow us to use this promising material as thermal insulating substrates in microsensors and microsystems. They are also great choices for usage as wire and cable insulation in nuclear reactors due to their superior electrical insulation.
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Affiliation(s)
- C M Kavitha
- Radiation and Materials Physics Lab, Department of Studies in Physics, Davanagere University, Shivagangotri, Davanagere, 577007, Karnataka, India
| | - K M Eshwarappa
- Radiation and Materials Physics Lab, Department of Studies in Physics, Davanagere University, Shivagangotri, Davanagere, 577007, Karnataka, India.
| | - Shivakumar Jagadish Shetty
- Nano and Functional Materials (NFML) Lab, Department of Physics, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, 576104, Karnataka, India
| | - S C Gurumurthy
- Nano and Functional Materials (NFML) Lab, Department of Physics, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, 576104, Karnataka, India.
| | - Srivathsava Surabhi
- Laboratorio de Nanocompuestos, Departamento de Ingeniería de Materiales (DIMAT), Facultad de Ingeniería (FI), Universidad de Concepción (UdeC), Concepción, Chile
- Laboratorio de Nanociencias y Nanotecnología, Facultad de Ciencias Físico Matemáticas (FCFM), Universidad Autónoma de Nuevo León (UANL), 66451, San Nicolás de los Garza, Nuevo León, Mexico
| | - T Niranjana Prabhu
- Department of Chemistry, M.S. Ramaiah University of Applied Sciences, Bangalore, Karnataka, India
| | - Jong-Ryul Jeong
- Department of Materials Science and Engineering, Graduate School of Energy Science and Technology, Chungnam National University, Daejeon, 34134, South Korea
| | - D V Morales
- Department of Environmental Chemistry, Faculty of Sciences, Centro de Energía; and Centro de Investigación en Biodiversidad y Ambientes Sustentables (CIBAS), Universidad Católica de la Santísima Concepción (UCSC), Concepción, Chile
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Variable Angle Spectroscopic Ellipsometry Characterization of Graphene Oxide in Methanol Films. CRYSTALS 2022. [DOI: 10.3390/cryst12050696] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
It has been widely established that solvents modify the functional groups on the graphene oxide (GO) basal plane and, thus, modify its reactivity. Despite the increasing interest in GO films, a less studied aspect is the influence of methanol on the refractive index of GO films. Herein, the Variable Angle Spectroscopic Ellipsometry (VASE) technique has been used to characterize the optical response of GO in methanol films (0.4 mg/mL) dip-coated on glass substrates. The ellipsometric data have been modeled using a Lorentz oscillator model. We have found that the energy of the oscillator at ~3.9 eV for GO in water shifts to ~4.2 eV for GO in methanol films.
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Abstract
A review of the authors’ research works on Variable-Angle Spectroscopy (VASE) of graphene-based films is presented. The interaction of graphene oxide (GO) with magnetron-sputtered metals is a promising research area. VASE optical models of GO thin films deposited on magnetron-sputtered titanium (Ti), silver (Ag) and gold (Au) are discussed. Moreover, the optical properties of graphene nanoplatelet (GNPS) films and reduced graphene oxide (RGO) stabilized with Poly(Sodium 4-Styrenesulfonate) (PSS) films, which are less studied graphene-related materials, are shown. Finally, different optical behaviors of chemical vapor deposition (CVD)-grown monolayer, bilayer, and trilayer graphene films on silicon and polyethylene terephthalate (PET) substrates are recapitulated.
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Graphene Oxide Coated Zinc Oxide Core–Shell Nanofibers for Enhanced Photocatalytic Performance and Durability. COATINGS 2020. [DOI: 10.3390/coatings10121183] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Recently, heterogeneous structured semiconductor photocatalysts have received significant interest in promoting global cleaning from the environmental pollution. Herein, we report the synthesis of graphene oxide (GO) wrapped zinc oxide (ZnO) core–shell nanofibers (ZnO@G CSNFs) by the simple core–shell electrospinning and subsequent annealing for efficient photocatalytic performance and stability. The heterostructured catalyst consisted of ZnO forming an enclosed core part while the GO was positioned on the surface, serving as a protective shell. Field emission scanning electron microscopy, high-resolution transmission electron microscopy and X-ray diffraction were used to confirm the synthesis of the desired product. Enhanced photocatalytic activity ZnO@G CSNFs was found compared to the corresponding ZnO NFs. Similarly, incorporation of GO into the ZnO nanofiber in a core–shell format significantly suppressed the photocorrosion. This study highlights the usefulness of using GO as the coating material to boost the photocatalytic performance of ZnO-based photocatalysts.
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Enhancement of Thermal and Mechanical Properties of Bismaleimide Using a Graphene Oxide Modified by Epoxy Silane. MATERIALS 2020; 13:ma13173836. [PMID: 32878091 PMCID: PMC7504111 DOI: 10.3390/ma13173836] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 08/25/2020] [Accepted: 08/25/2020] [Indexed: 11/23/2022]
Abstract
A thermosetting resin system, based on bismaleimide (BMI), has been developed via copolymerization of 4,4′-diaminodiphenylsulfone with a newly synthesized graphene oxide modified using epoxy silane (ES-GO). The effect of ES-GO on the thermomechanical and mechanical properties of cured modified resin was studied. To evaluate the efficiency of the modified BMI systems, the composite samples using glass fiber cloth were molded and tested. Thermogravimetric analysis indicates that the cured sample systems displays a high char yield at lower concentrations of ES-GO (≤0.5 wt.%), suggesting an improved thermal stability. Using dynamic mechanical analysis, a marked increase in glass transition temperature (Tg) with increasing ES-GO content was observed. Analysis of mechanical properties reveals a possible effect of ES-GO as a toughener. The results also showed that the addition of 0.3 wt.% ES-GO maximizes the toughness of the modified resin systems, which was further confirmed by the result of analysis of fracture surfaces. At the same time, a molded composite with ES-GO showed improved mechanical properties and retention rate at 150 °C as compared to that made with neat resin.
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