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18 pages, 5980 KiB

Open AccessArticle

Release Profiles of Carvacrol or Chlorhexidine of PLA/Graphene Nanoplatelets Membranes Prepared Using Electrospinning and Solution Blow Spinning: A Comparative Study

by Roberto Scaffaro, Luca Settanni and Emmanuel Fortunato Gulino

Molecules 2023, 28(4), 1967; https://doi.org/10.3390/molecules28041967 - 19 Feb 2023

Cited by 15 | Viewed by 2621

Abstract

Nanofibrous membranes are often the core components used to produce devices for a controlled release and are frequently prepared by electrospinning (ES). However, ES requires high production times and costs and is not easy to scale. Recently, solution blow spinning (SBS) has been [...] Read more.

Nanofibrous membranes are often the core components used to produce devices for a controlled release and are frequently prepared by electrospinning (ES). However, ES requires high production times and costs and is not easy to scale. Recently, solution blow spinning (SBS) has been proposed as an alternative technique for the production of nanofibrous membranes. In this study, a comparison between these two techniques is proposed. Poly (lactic acid)-based nanofibrous membranes were produced by electrospinning (ES) and solution blow spinning (SBS) in order to evaluate the different effect of liquid (carvacrol, CRV) or solid (chlorhexidine, CHX) molecules addition on the morphology, structural properties, and release behavior. The outcomes revealed that both ES and SBS nanofibrous mat allowed for obtaining a controlled release up to 500 h. In detail, the lower wettability of the SBS system allowed for slowing down the CRV release kinetics, compared to the one obtained for ES membranes. On the contrary, with SBS, a faster CHX release can be obtained due to its more hydrophilic behavior. Further, the addition of graphene nanoplatelets (GNP) led to a decrease in wettability and allowed for a slowing down of the release kinetics in the whole of the systems. Full article

(This article belongs to the Special Issue Fullerenes, Graphenes and Carbon Nanotubes Nanocomposites)

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19 pages, 7119 KiB

Open AccessArticle

Improved Strength and Heat Distortion Temperature of Emi-Aromatic Polyamide 10T-co-1012 (PA10T/1012)/GO Composites via In Situ Polymerization

by Yanchao Dong, Pingli Wang, Zhonglai Ren, Tianyuan Liu, Zhichao Zhen, Bo Lu, Fei Li and Junhui Ji

Molecules 2023, 28(4), 1960; https://doi.org/10.3390/molecules28041960 - 18 Feb 2023

Cited by 7 | Viewed by 1990

Abstract

In this paper, an effective method for preparing poly (p-phenylene terephthalamide) -co- poly (dodecanedioyl) decylamine (PA10T/1012)/graphene oxide (GO) composites by pre-dispersion and one-step in situ polymerization was proposed for the first time. During the process of polycondensation, the condensation between the terminal amino [...] Read more.

In this paper, an effective method for preparing poly (p-phenylene terephthalamide) -co- poly (dodecanedioyl) decylamine (PA10T/1012)/graphene oxide (GO) composites by pre-dispersion and one-step in situ polymerization was proposed for the first time. During the process of polycondensation, the condensation between the terminal amino groups of PA10T/1012 chains and the oxygen-containing functional groups of GO allowed nylon to be grafted onto graphene sheets. The effects of polymer grafting on the thermal and mechanical properties of (PA10T/1012)/GO composites were studied in detail. Due to the interaction between PA10T/1012 grafted graphene sheets and its matrix, GO is well dispersed in the PA10T/1012 matrix and physically entangled with it, forming a cross-linked network structure of polymer bridged graphene, thus obtaining enhanced tensile strength, tensile modulus and impact strength. More importantly, benefiting from the cross-linked network structure, the heat distortion temperature (HDT) of the composite is greatly increased from 77.3 °C to 144.2 °C. This in situ polycondensation method opens a new avenue to prepare polycondensate graphene-based composites with high strength and high heat distortion temperatures. Full article

(This article belongs to the Special Issue Fullerenes, Graphenes and Carbon Nanotubes Nanocomposites)

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18 pages, 5609 KiB

Open AccessArticle

Zirconium Molybdate Nanocomposites’ Sensing Platform for the Sensitive and Selective Electrochemical Detection of Adefovir

by Wenming Li, Jingyun Xiao, Liangyuan Yao, Yanping Wei, Jinsong Zuo, Weili Zeng, Jianhua Ding and Quanguo He

Molecules 2022, 27(18), 6022; https://doi.org/10.3390/molecules27186022 - 15 Sep 2022

Cited by 5 | Viewed by 1877

Abstract

Adefovir (ADV) is an anti-retroviral drug, which can be used to treat acquired immune deficiency syndrome (AIDS) and chronic hepatitis B (CHB), so its quantitative analysis is of great significance. In this work, zirconium molybdate (ZrMo₂O₈) was synthesized by [...] Read more.

Adefovir (ADV) is an anti-retroviral drug, which can be used to treat acquired immune deficiency syndrome (AIDS) and chronic hepatitis B (CHB), so its quantitative analysis is of great significance. In this work, zirconium molybdate (ZrMo₂O₈) was synthesized by a wet chemical method, and a composite with multi-walled carbon nanotubes (MWCNTs) was made. ZrMo₂O₈-MWCNTs composite was dropped onto the surface of a glassy carbon electrode (GCE) to prepare ZrMo₂O₈-MWCNTs/GCE, and ZrMo₂O₈-MWCNTs/GCE was used in the electrochemical detection of ADV for the first time. The preparation method is fast and simple. The materials were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and cyclic voltammetry (CV). It was electrochemically analysed by differential pulse voltammetry (DPV). Compared with single-material modified electrodes, ZrMo₂O₈-MWCNTs/GCE showed a vastly improved electrochemical response to ADV. Moreover, the sensor complements the study of the electrochemical detection of ADV. Under optimal conditions, the proposed electrochemical method showed a wide linear range (from 1 to 100 μM) and a low detection limit (0.253 μM). It was successfully tested in serum and urine. In addition, the sensor has the advantages of a simple preparation, fast response, good reproducibility and repeatability. It may be helpful in the potential applications of other substances with similar structures. Full article

(This article belongs to the Special Issue Fullerenes, Graphenes and Carbon Nanotubes Nanocomposites)

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24 pages, 12922 KiB

Open AccessArticle

The Role of Phase Migration of Carbon Nanotubes in Melt-Mixed PVDF/PE Polymer Blends for High Conductivity and EMI Shielding Applications

by Calin Lencar, Shashank Ramakrishnan, Elnaz Erfanian and Uttandaraman Sundararaj

Molecules 2022, 27(3), 933; https://doi.org/10.3390/molecules27030933 - 29 Jan 2022

Cited by 15 | Viewed by 3305

Abstract

In this work, the effects of blend ratio and mixing time on the migration of multi-walled carbon nanotubes (MWCNTs) within poly(vinylidene fluoride) (PVDF)/polyethylene (PE) blends are studied. A novel two-step mixing approach was used to pre-localize MWCNTs within the PE phase, and subsequently [...] Read more.

In this work, the effects of blend ratio and mixing time on the migration of multi-walled carbon nanotubes (MWCNTs) within poly(vinylidene fluoride) (PVDF)/polyethylene (PE) blends are studied. A novel two-step mixing approach was used to pre-localize MWCNTs within the PE phase, and subsequently allow them to migrate into the thermodynamically favored PVDF phase. Light microscopy images confirm that MWCNTs migrate from PE to PVDF, and transmission electron microscopy (TEM) images show individual MWCNTs migrating fully into PVDF, while agglomerates remained trapped at the PVDF/PE interface. PVDF:PE 50:50 and 20:80 polymer blend nanocomposites with 2 vol% MWCNTs exhibit exceptional electromagnetic interference shielding effectiveness (EMI SE) at 10 min of mixing (13 and 16 dB, respectively-at a thickness of 0.45 mm), when compared to 30 s of mixing (11 and 12 dB, respectively), suggesting the formation of more interconnected MWCNT networks over time. TEM images show that these improved microstructures are concentrated on the PE side of the PVDF/PE interface. A modified version of the “Slim-Fast-Mechanism” is proposed to explain the migration behavior of MWCNTs within the PVDF/PE blend. In this theory, MWCNTs approaching perpendicular to the interface penetrate the PVDF/PE interface, while those approaching in parallel or as MWCNT agglomerates remain trapped. Trapped MWCNTs act as barriers to additional MWCNTs, regardless of geometry. This mechanism is verified via TEM and scanning electron microscopy and suggests the feasibility of localizing MWCNTs at the interface of PVDF/PE blends. Full article

(This article belongs to the Special Issue Fullerenes, Graphenes and Carbon Nanotubes Nanocomposites)

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18 pages, 6092 KiB

Open AccessArticle

Schemes for Single Electron Transistor Based on Double Quantum Dot Islands Utilizing a Graphene Nanoscroll, Carbon Nanotube and Fullerene

by Vahideh Khademhosseini, Daryoosh Dideban, Mohammad Taghi Ahmadi and Hadi Heidari

Molecules 2022, 27(1), 301; https://doi.org/10.3390/molecules27010301 - 4 Jan 2022

Cited by 6 | Viewed by 3073

Abstract

The single electron transistor (SET) is a nanoscale switching device with a simple equivalent circuit. It can work very fast as it is based on the tunneling of single electrons. Its nanostructure contains a quantum dot island whose material impacts on the device [...] Read more.

The single electron transistor (SET) is a nanoscale switching device with a simple equivalent circuit. It can work very fast as it is based on the tunneling of single electrons. Its nanostructure contains a quantum dot island whose material impacts on the device operation. Carbon allotropes such as fullerene (C₆₀), carbon nanotubes (CNTs) and graphene nanoscrolls (GNSs) can be utilized as the quantum dot island in SETs. In this study, multiple quantum dot islands such as GNS-CNT and GNS-C₆₀ are utilized in SET devices. The currents of two counterpart devices are modeled and analyzed. The impacts of important parameters such as temperature and applied gate voltage on the current of two SETs are investigated using proposed mathematical models. Moreover, the impacts of CNT length, fullerene diameter, GNS length, and GNS spiral length and number of turns on the SET’s current are explored. Additionally, the Coulomb blockade ranges (CB) of the two SETs are compared. The results reveal that the GNS-CNT SET has a lower Coulomb blockade range and a higher current than the GNS-C₆₀ SET. Their charge stability diagrams indicate that the GNS-CNT SET has smaller Coulomb diamond areas, zero-current regions, and zero-conductance regions than the GNS-C₆₀ SET. Full article

(This article belongs to the Special Issue Fullerenes, Graphenes and Carbon Nanotubes Nanocomposites)

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14 pages, 60989 KiB

Open AccessArticle

Theoretical Encapsulation of Fluorouracil (5-FU) Anti-Cancer Chemotherapy Drug into Carbon Nanotubes (CNT) and Boron Nitride Nanotubes (BNNT)

by Maryam Zarghami Dehaghani, Farrokh Yousefi, S. Mohammad Sajadi, Muhammad Tajammal Munir, Otman Abida, Sajjad Habibzadeh, Amin Hamed Mashhadzadeh, Navid Rabiee, Ebrahim Mostafavi and Mohammad Reza Saeb

Molecules 2021, 26(16), 4920; https://doi.org/10.3390/molecules26164920 - 13 Aug 2021

Cited by 27 | Viewed by 4720

Abstract

Introduction: Chemotherapy with anti-cancer drugs is considered the most common approach for killing cancer cells in the human body. However, some barriers such as toxicity and side effects would limit its usage. In this regard, nano-based drug delivery systems have emerged as cost-effective [...] Read more.

Introduction: Chemotherapy with anti-cancer drugs is considered the most common approach for killing cancer cells in the human body. However, some barriers such as toxicity and side effects would limit its usage. In this regard, nano-based drug delivery systems have emerged as cost-effective and efficient for sustained and targeted drug delivery. Nanotubes such as carbon nanotubes (CNT) and boron nitride nanotubes (BNNT) are promising nanocarriers that provide the cargo with a large inner volume for encapsulation. However, understanding the insertion process of the anti-cancer drugs into the nanotubes and demonstrating drug-nanotube interactions starts with theoretical analysis. Methods: First, interactions parameters of the atoms of 5-FU were quantified from the DREIDING force field. Second, the storage capacity of BNNT (8,8) was simulated to count the number of drugs 5-FU encapsulated inside the cavity of the nanotubes. In terms of the encapsulation process of the one drug 5-FU into nanotubes, it was clarified that the drug 5-FU was more rapidly adsorbed into the cavity of the BNNT compared with the CNT due to the higher van der Waals (vdW) interaction energy between the drug and the BNNT. Results: The obtained values of free energy confirmed that the encapsulation process of the drug inside the CNT and BNNT occurred spontaneously with the free energies of −14 and −25 kcal·mol⁻¹, respectively. Discussion: However, the lower value of the free energy in the system containing the BNNT unraveled more stability of the encapsulated drug inside the cavity of the BNNT comparing the system having CNT. The encapsulation of Fluorouracil (5-FU) anti-cancer chemotherapy drug (commercial name: Adrucil^®) into CNT (8,8) and BNNT (8,8) with the length of 20 Å in an aqueous solution was discussed herein applying molecular dynamics (MD) simulation. Full article

(This article belongs to the Special Issue Fullerenes, Graphenes and Carbon Nanotubes Nanocomposites)

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11 pages, 3339 KiB

Open AccessArticle

Effect of the Nanotube Radius and the Volume Fraction on the Mechanical Properties of Carbon Nanotube-Reinforced Aluminum Metal Matrix Composites

by Myung Eun Suk

Molecules 2021, 26(13), 3947; https://doi.org/10.3390/molecules26133947 - 28 Jun 2021

Cited by 17 | Viewed by 2502

Abstract

By using the advantages of carbon nanotubes (CNTs), such as their excellent mechanical properties and low density, CNT-reinforced metal matrix composites (MMCs) are expected to overcome the limitations of conventional metal materials, i.e., their high density and low ductility. To understand the behavior [...] Read more.

By using the advantages of carbon nanotubes (CNTs), such as their excellent mechanical properties and low density, CNT-reinforced metal matrix composites (MMCs) are expected to overcome the limitations of conventional metal materials, i.e., their high density and low ductility. To understand the behavior of composite materials, it is necessary to observe the behavior at the molecular level and to understand the effect of various factors, such as the radius and content of CNTs. Therefore, in this study, the effect of the CNT radius and content on the mechanical properties of CNT-Al composites was observed using a series of molecular dynamics simulations, particularly focusing on MMCs with a high CNT content and large CNT diameter. The mechanical properties, such as the strength and stiffness, were increased with an increasing CNT radius. As the CNT content increased, the strength and stiffness increased; however, the fracture strain was not affected. The behavior of double-walled carbon nanotubes (DWNTs) and single-walled carbon nanotubes (SWNTs) was compared through the decomposition of the stress–strain curve and observations of the atomic stress field. The fracture strain increased significantly for SWNT-Al as the tensile force was applied in the axial direction of the armchair CNTs. In the case of DWNTs, an early failure was initiated at the inner CNTs. In addition, the change in the elastic modulus according to the CNT content was predicted using the modified rule of mixture. This study is expected to be useful for the design and development of high-performance MMCs reinforced by CNTs. Full article

(This article belongs to the Special Issue Fullerenes, Graphenes and Carbon Nanotubes Nanocomposites)

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12 pages, 2788 KiB

Open AccessArticle

Nano Carbon Doped Polyacrylamide Gel Electrolytes for High Performance Supercapacitors

by Samar Azizighannad, Zhiqian Wang, Zain Siddiqui, Vivek Kumar and Somenath Mitra

Molecules 2021, 26(9), 2631; https://doi.org/10.3390/molecules26092631 - 30 Apr 2021

Cited by 12 | Viewed by 2688

Abstract

Novel polyacrylamide gel electrolytes (PGEs) doped with nano carbons with enhanced electrochemical, thermal, and mechanical properties are presented. Carboxylated carbon nanotubes (fCNTs), graphene oxide sheets (GO), and the hybrid of fCNT/GO were embedded in the PGEs to serve as supercapacitor (SC) electrolytes. Thermal [...] Read more.

Novel polyacrylamide gel electrolytes (PGEs) doped with nano carbons with enhanced electrochemical, thermal, and mechanical properties are presented. Carboxylated carbon nanotubes (fCNTs), graphene oxide sheets (GO), and the hybrid of fCNT/GO were embedded in the PGEs to serve as supercapacitor (SC) electrolytes. Thermal stability of the unmodified PGE increased with the addition of the nano carbons which led to lower capacitance degradation and longer cycling life of the SCs. The fCNT/GO-PGE showed the best thermal stability, which was 50% higher than original PGE. Viscoelastic properties of PGEs were also improved with the incorporation of GO and fCNT/GO. Oxygen-containing functional groups in GO and fCNT/GO hydrogen bonded with the polymer chains and improved the elasticity of PGEs. The fCNT-PGE demonstrated a slightly lower viscous strain uninform distribution of CNTs in the polymer matrix and the defects formed within. Furthermore, ion diffusion between GO layers was enhanced in fCNT/GO-PGE because fCNT decreased the aggregation of GO sheets and improved the ion channels, increasing the gel ionic conductivity from 41 to 132 mS cm⁻¹. Finally, MnO₂-based supercapacitors using PGE, fCNT-PGE, GO-PGE, and fCNT/GO-PGE electrolytes were fabricated with the electrode-specific capacitance measured to be 39.5, 65.5, 77.6, and 83.3 F·g⁻¹, respectively. This research demonstrates the effectiveness of nano carbons as dopants in polymer gel electrolytes for property enhancements. Full article

(This article belongs to the Special Issue Fullerenes, Graphenes and Carbon Nanotubes Nanocomposites)

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17 pages, 5388 KiB

Open AccessArticle

Investigation into the Structural, Chemical and High Mechanical Reforms in B₄C with Graphene Composite Material Substitution for Potential Shielding Frame Applications

by Ibrahim M. Alarifi

Molecules 2021, 26(7), 1921; https://doi.org/10.3390/molecules26071921 - 29 Mar 2021

Cited by 3 | Viewed by 2848

Abstract

In this work, boron carbide and graphene nanoparticle composite material (B₄C–G) was investigated using an experimental approach. The composite material prepared with the two-step stir casting method showed significant hardness and high melting point attributes. Scanning electron microscopy (SEM), along with [...] Read more.

In this work, boron carbide and graphene nanoparticle composite material (B₄C–G) was investigated using an experimental approach. The composite material prepared with the two-step stir casting method showed significant hardness and high melting point attributes. Scanning electron microscopy (SEM), along with energy dispersive X-ray spectroscopy (EDS) analysis, indicated 83.65%, 17.32%, and 97.00% of boron carbide + 0% graphene nanoparticles chemical compositions for the C-atom, Al-atom, and B₄C in the compound studied, respectively. The physical properties of all samples’ B₄C–G like density and melting point were 2.4 g/cm³ density and 2450 °C, respectively, while the grain size of B₄C–G was in the range of 0.8 ± 0.2 µm. XRD, FTIR, and Raman spectroscopic analysis was also performed to investigate the chemical compositions of the B₄C–G composite. The molding press composite machine was a fabrication procedure that resulted in the formation of outstanding materials by utilizing the sintering process, including heating and pressing the materials. For mechanical properties, high fracture toughness and tensile strength of B₄C–G composites were analyzed according to ASTM standard designs. The detailed analysis has shown that with 6% graphene content in B₄C, the composite material portrays a high strength of 134 MPa and outstanding hardness properties. Based on these findings, it is suggested that the composite materials studied exhibit novel features suitable for use in the application of shielding frames. Full article

(This article belongs to the Special Issue Fullerenes, Graphenes and Carbon Nanotubes Nanocomposites)

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12 pages, 5001 KiB

Open AccessArticle

Development of Paper Actuators Based on Carbon-Nanotube-Composite Paper

by Takahiro Ampo and Takahide Oya

Molecules 2021, 26(5), 1463; https://doi.org/10.3390/molecules26051463 - 8 Mar 2021

Cited by 9 | Viewed by 2490

Abstract

We propose a unique soft actuator—a paper actuator—based on carbon-nanotube-composite paper (CNT-composite paper), which is a composite of carbon nanotubes (CNTs) and paper. CNT-composite paper has highly efficient properties because of the contained CNTs, such as high electrical conductivity and semiconducting properties. We [...] Read more.

We propose a unique soft actuator—a paper actuator—based on carbon-nanotube-composite paper (CNT-composite paper), which is a composite of carbon nanotubes (CNTs) and paper. CNT-composite paper has highly efficient properties because of the contained CNTs, such as high electrical conductivity and semiconducting properties. We are considering using CNT-composite paper for various devices. In this study, we successfully developed a paper actuator. We determined the structure of the paper actuator by referencing that of bucky-gel actuators. The actuator operates using the force generated by the movement of ions. In addition to making the paper actuator, we also attempted to improve its performance, using pressure as an index and an electronic scale to measure the pressure. We investigated the optimal dispersant for use in paper actuators, expecting the residual dispersant on the CNT-composite paper to affect the performance differently depending on the type of dispersant. Referring to research on bucky-gel actuators, we also found that the addition of carbon powder to the electrode layers is effective in improving the pressure for paper actuators. We believe that the paper actuator could be used in various situations due to its ease of processing. Full article

(This article belongs to the Special Issue Fullerenes, Graphenes and Carbon Nanotubes Nanocomposites)

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19 pages, 6547 KiB

Open AccessArticle

The Localization Behavior of Different CNTs in PC/SAN Blends Containing a Reactive Component

by Marén Gültner, Regine Boldt, Petr Formanek, Dieter Fischer, Frank Simon and Petra Pötschke

Molecules 2021, 26(5), 1312; https://doi.org/10.3390/molecules26051312 - 1 Mar 2021

Cited by 2 | Viewed by 2103

Abstract

Co-continuous blend systems of polycarbonate (PC), poly(styrene-co-acrylonitrile) (SAN), commercial non-functionalized multi-walled carbon nanotubes (MWCNTs) or various types of commercial and laboratory functionalized single-walled carbon nanotubes (SWCNTs), and a reactive component (RC, N-phenylmaleimide styrene maleic anhydride copolymer) were melt compounded in [...] Read more.

Co-continuous blend systems of polycarbonate (PC), poly(styrene-co-acrylonitrile) (SAN), commercial non-functionalized multi-walled carbon nanotubes (MWCNTs) or various types of commercial and laboratory functionalized single-walled carbon nanotubes (SWCNTs), and a reactive component (RC, N-phenylmaleimide styrene maleic anhydride copolymer) were melt compounded in one step in a microcompounder. The blend system is immiscible, while the RC is miscible with SAN and contains maleic anhydride groups that have the potential to reactively couple with functional groups on the surface of the nanotubes. The influence of the RC on the localization of MWCNTs and SWCNTs (0.5 wt.%) was investigated by transmission electron microscopy (TEM) and energy-filtered TEM. In PC/SAN blends without RC, MWCNTs are localized in the PC component. In contrast, in PC/SAN-RC, the MWCNTs localize in the SAN-RC component, depending on the RC concentration. By adjusting the MWCNT/RC ratio, the localization of the MWCNTs can be tuned. The SWCNTs behave differently compared to the MWCNTs in PC/SAN-RC blends and their localization occurs either only in the PC or in both blend components, depending on the type of the SWCNTs. CNT defect concentration and surface functionalities seem to be responsible for the localization differences. Full article

(This article belongs to the Special Issue Fullerenes, Graphenes and Carbon Nanotubes Nanocomposites)

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11 pages, 6344 KiB

Open AccessArticle

Electrical Properties Enhancement of Carbon Nanotube Yarns by Cyclic Loading

by Orli Weizman, Joey Mead, Hanna Dodiuk and Samuel Kenig

Molecules 2020, 25(20), 4824; https://doi.org/10.3390/molecules25204824 - 20 Oct 2020

Cited by 8 | Viewed by 2670

Abstract

Carbon nanotube yarns (CNTYs) possess low density, high conductivity, high strength, and moderate flexibility. These intrinsic properties allow them to be a preferred choice for use as conductive elements in high-performance composites. To fully exploit their potential as conductive reinforcing elements, further improvement [...] Read more.

Carbon nanotube yarns (CNTYs) possess low density, high conductivity, high strength, and moderate flexibility. These intrinsic properties allow them to be a preferred choice for use as conductive elements in high-performance composites. To fully exploit their potential as conductive reinforcing elements, further improvement in their electrical conductivity is needed. This study demonstrates that tensile cyclic loading under ambient conditions improves the electrical conductivity of two types of CNTYs. The results showed that the electrical resistance of untreated CNTYs was reduced by 80% using cyclic loading, reaching the resistance value of the drawn acid-treated CNTYs. Scanning electron microscopy showed that cyclic loading caused orientation and compaction of the CNT bundles that make up the CNTYs, resulting in significantly improved electrical conductivity of the CNTYs. Furthermore, the elastic modulus was increased by 20% while preserving the tensile strength. This approach has the potential to replace the environmentally unfriendly acid treatment currently used to enhance the conductivity of CNTYs. Full article

(This article belongs to the Special Issue Fullerenes, Graphenes and Carbon Nanotubes Nanocomposites)

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24 pages, 21574 KiB

Open AccessArticle

Stacking Interactions of Poly Para-Phenylene Vinylene Oligomers with Graphene and Single-Walled Carbon Nanotubes: A Molecular Dynamics Approach

by Nii Amah Dagadu, Shahram Ajori, Yaw Delali Bensah, Kwabena Kan-Dapaah, Stephen Kofi Armah, Boateng Onwona-Agyeman and Abu Yaya

Molecules 2020, 25(20), 4812; https://doi.org/10.3390/molecules25204812 - 20 Oct 2020

Viewed by 2576

Abstract

This study is meant to address the understanding of the interactions between poly para-phenylene vinylene (PPV) oligomers, graphene and single-walled carbon nanotubes (SWCNT). To this end, the binding energies of the PPV oligomers with graphene and SWCNTs were investigated. Calculations are performed and [...] Read more.

This study is meant to address the understanding of the interactions between poly para-phenylene vinylene (PPV) oligomers, graphene and single-walled carbon nanotubes (SWCNT). To this end, the binding energies of the PPV oligomers with graphene and SWCNTs were investigated. Calculations are performed and the parameters related to van der Waal vdW interactions are discussed to achieve and confirm the crystallization of oligomers of PPV into herringbone (HB) structure arrangement, which is known to be the most stable conformation at 300 K. Finally, the interfacial interactions between crystal PPV, graphene and SWCNT are carried out. According to the results, the intramolecular potential energies of PPV chains are found to increase linearly with each extending PPV monomer unit by approximately 50 kcal/mol. Moreover, the interfacial interaction properties analysis using radial distribution functions (RDFs) for PPV-graphene and PPV-SWCNT show significant disordering of the arrangement of molecules, which is more pronounced for PPV-SWCNT than that in PPV-graphene. The radius of gyration (

R_{g}

) profiles show a net decrease of

\sim - 0.8

, for PPV-graphene with different surface coverage, and, a net increase of

\sim + 0.6

, for PPV-SWCNT; meaning that, the binding between PPV-graphene is much stronger than with PPV-SWCNT. Full article

(This article belongs to the Special Issue Fullerenes, Graphenes and Carbon Nanotubes Nanocomposites)

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Review

Jump to: Research

32 pages, 8099 KiB

Open AccessReview

Nanocarbon-Based Flame Retardant Polymer Nanocomposites

by Yuan Yang, José Luis Díaz Palencia, Na Wang, Yan Jiang and De-Yi Wang

Molecules 2021, 26(15), 4670; https://doi.org/10.3390/molecules26154670 - 2 Aug 2021

Cited by 41 | Viewed by 5955

Abstract

In recent years, nanocarbon materials have attracted the interest of researchers due to their excellent properties. Nanocarbon-based flame retardant polymer composites have enhanced thermal stability and mechanical properties compared with traditional flame retardant composites. In this article, the unique structural features of nanocarbon-based [...] Read more.

In recent years, nanocarbon materials have attracted the interest of researchers due to their excellent properties. Nanocarbon-based flame retardant polymer composites have enhanced thermal stability and mechanical properties compared with traditional flame retardant composites. In this article, the unique structural features of nanocarbon-based materials and their use in flame retardant polymeric materials are initially introduced. Afterwards, the flame retardant mechanism of nanocarbon materials is described. The main discussions include material components such as graphene, carbon nanotubes, fullerene (in preparing resins), elastomers, plastics, foams, fabrics, and film–matrix materials. Furthermore, the flame retardant properties of carbon nanomaterials and their modified products are summarized. Carbon nanomaterials not only play the role of a flame retardant in composites, but also play an important role in many aspects such as mechanical reinforcement. Finally, the opportunities and challenges for future development of carbon nanomaterials in flame-retardant polymeric materials are briefly discussed. Full article

(This article belongs to the Special Issue Fullerenes, Graphenes and Carbon Nanotubes Nanocomposites)

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19 pages, 6291 KiB

Open AccessFeature PaperReview

Zero-to-Two Nanoarchitectonics: Fabrication of Two-Dimensional Materials from Zero-Dimensional Fullerene

by Guoping Chen, Lok Kumar Shrestha and Katsuhiko Ariga

Molecules 2021, 26(15), 4636; https://doi.org/10.3390/molecules26154636 - 30 Jul 2021

Cited by 21 | Viewed by 4283

Abstract

Nanoarchitectonics of two-dimensional materials from zero-dimensional fullerenes is mainly introduced in this short review. Fullerenes are simple objects with mono-elemental (carbon) composition and zero-dimensional structure. However, fullerenes and their derivatives can create various types of two-dimensional materials. The exemplified approaches demonstrated fabrications of [...] Read more.

Nanoarchitectonics of two-dimensional materials from zero-dimensional fullerenes is mainly introduced in this short review. Fullerenes are simple objects with mono-elemental (carbon) composition and zero-dimensional structure. However, fullerenes and their derivatives can create various types of two-dimensional materials. The exemplified approaches demonstrated fabrications of various two-dimensional materials including size-tunable hexagonal fullerene nanosheet, two-dimensional fullerene nano-mesh, van der Waals two-dimensional fullerene solid, fullerene/ferrocene hybrid hexagonal nanosheet, fullerene/cobalt porphyrin hybrid nanosheet, two-dimensional fullerene array in the supramolecular template, two-dimensional van der Waals supramolecular framework, supramolecular fullerene liquid crystal, frustrated layered self-assembly from two-dimensional nanosheet, and hierarchical zero-to-one-to-two dimensional fullerene assembly for cell culture. Full article

(This article belongs to the Special Issue Fullerenes, Graphenes and Carbon Nanotubes Nanocomposites)

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22 pages, 1524 KiB

Open AccessReview

Toxicity Studies on Graphene-Based Nanomaterials in Aquatic Organisms: Current Understanding

by Nemi Malhotra, Oliver B. Villaflores, Gilbert Audira, Petrus Siregar, Jiann-Shing Lee, Tzong-Rong Ger and Chung-Der Hsiao

Molecules 2020, 25(16), 3618; https://doi.org/10.3390/molecules25163618 - 9 Aug 2020

Cited by 65 | Viewed by 6252

Abstract

Graphene and its oxide are nanomaterials considered currently to be very promising because of their great potential applications in various industries. The exceptional physiochemical properties of graphene, particularly thermal conductivity, electron mobility, high surface area, and mechanical strength, promise development of novel or [...] Read more.

Graphene and its oxide are nanomaterials considered currently to be very promising because of their great potential applications in various industries. The exceptional physiochemical properties of graphene, particularly thermal conductivity, electron mobility, high surface area, and mechanical strength, promise development of novel or enhanced technologies in industries. The diverse applications of graphene and graphene oxide (GO) include energy storage, sensors, generators, light processing, electronics, and targeted drug delivery. However, the extensive use and exposure to graphene and GO might pose a great threat to living organisms and ultimately to human health. The toxicity data of graphene and GO is still insufficient to point out its side effects to different living organisms. Their accumulation in the aquatic environment might create complex problems in aquatic food chains and aquatic habitats leading to debilitating health effects in humans. The potential toxic effects of graphene and GO are not fully understood. However, they have been reported to cause agglomeration, long-term persistence, and toxic effects penetrating cell membrane and interacting with cellular components. In this review paper, we have primarily focused on the toxic effects of graphene and GO caused on aquatic invertebrates and fish (cell line and organisms). Here, we aim to point out the current understanding and knowledge gaps of graphene and GO toxicity. Full article

(This article belongs to the Special Issue Fullerenes, Graphenes and Carbon Nanotubes Nanocomposites)

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