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Item Metadata only Metal-organic frameworks containing solid-state electrolytes for lithium metal batteries and beyond(Royal Society of Chemistry, 2021) Chen, T.; Chen, S.; Chen, Y.; Zhao, M.; Losic, D.; Zhang, S.For solid-state Li and other metal batteries, solid-state electrolytes (SSEs) are a bridge between electrodes, and are significant in determining the behavior of batteries. Thus, constructing stable and excellent SSEs is vital for the feasible application of metal batteries. Because of their unique and multifunctional properties, namely unsaturated metal sites, tunable structure, and high specific surface area, porous metal–organic frameworks (MOFs) have been applied to SSEs to enhance the performance of metal batteries. In this review, the mechanisms of MOFs within polymer electrolytes on improving the Li-ion movement, stabilizing the solid/solid interfacial contact, and prohibiting the Li dendrite are briefly summarized. The multiple factors of MOF-based SSEs, including MOF structures, unsaturated metal sites, incorporation with ionic liquids, different organic ligands, pore size and nano/micro hierarchical structure that affect the battery performance are comprehensively discussed. Moreover, the mechanism and advancement of MOF-based SSEs for other metal batteries, including Na, Zn, and Mg batteries, are also illustrated. Eventually, new insights and future prospects in terms of MOF-based SSEs are proposed to stimulate more innovative approaches for the commercial applications of Li and other metal batteries.Item Metadata only Large interspaced layered potassium niobate nanosheet arrays as an ultrastable anode for potassium ion capacitor(Elsevier BV, 2021) Pham, H.D.; Chodankar, N.R.; Jadhav, S.D.; Jayaramulu, K.; Nanjundan, A.K.; Dubal, D.P.Potassium-ion battery (KIB) is a promising technology for large-scale energy storage applications due to their low cost, theoretically high energy density and abundant resources. However, the development of KIBs is hin- dered by the sluggish K + transport kinetics and the structural instability of the electrode materials during K + intercalation/de-intercalation. In the present investigation, we have designed a potassium-ion capacitor (KIC) using layered potassium niobate (K 4 Nb 6 O 17 , KNO) nanosheet arrays as anode and orange-peel derived activated carbons (OPAC) as fast capacitive cathode materials. The systematic electrochemical analysis with the ex-situ characterizations demonstrates that KNO-anode exhibits highly stable layered structure with excellent reversibil- ity during K + insertion/de-insertion. After optimization, the fabricated KNO//OPAC delivers both a high energy density of 116 Wh/kg and high power density of 10,808 W/kg, which is significantly higher than other similar hybrid devices. The cell also displays long term cycling stability over 5000 cycles, with 87 % of capacity reten- tion. This study highlights the utilization of layered nanosheet arrays of niobates to achieve superior K ‐storage for KICs, paving the way towards the development of high ‐performance anodes for post lithium ‐ion batteries.Item Metadata only Enhancing the performance and environmental impact of alkali-activated binder-based composites containing graphene oxide and industrial by-products(Elsevier, 2021) Ho, V.D.; Gholampour, A.; Losic, D.; Ozbakkaloglu, T.The growing production of industrial by-products, such as fly ash (FA), ground granulated blast furnace slag (GGBS), and lead smelter slag (LSS), has resulted in significant negative impacts on the environment. Meanwhile, the high demand for ordinary Portland cement (OPC) and the over-exploitation of natural sand (NS) has also negatively impacted the ecosystem. The use of the mentioned industrial by-products to replace OPC and NS offers great potential for reducing the environmental impact of both the industrial wastes and conventional concrete. This study investigates the possible improvements to mechanical and durability properties of combined FA and GGBS-based alkali-activated binder (AAB) mortars prepared with NS and LSS sands through the addition of graphene oxide (GO). The results show that the increase of GGBS content in the binder of AAB composites (i.e. 20% and 50% GGBS) results in a significant increase in compressive and tensile strengths, and a decrease in drying shrinkage, flowability, and water absorption of the mortars. It is found that mortars with 0.05% and 0.1% GO additives provide better mechanical and durability properties than the control mortars. The study also shows that oxygen functional groups of GO sheets have been reduced in alkaline solution, and they were turned into the form of reduced graphene oxide (rGO) sheets with a higher wrinkling degree in their shapes. The better performance of AAB mortars containing GO additives is attributed to the improvement of the gel matrix formed through the combination of chemical and mechanical interactions between rGO sheets and the gel products. The outcomes of this study point to the great potential of the combined use of waste materials and GO additives to enhance the performance of AAB composites.Item Metadata only Enhancement of dielectric and ferroelectric properties in flexible polymer for energy storage applications(Elsevier, 2020) Ishaq, S.; Kanwal, F.; Atiq, S.; Noreen, S.; Moussa, M.; Azhar, U.; Losic, D.In the present paper, synthesis and characterizations of flexible dielectric and ferroelectric polymer films combining different ratios of graphene, barium titanate and polydimethylsiloxane are presented. Broad range of characterization techniques were carried out to confirm their, morphological, structural, chemical, thermal and mechanical (flexibility, stretching, bending and twisting) characteristics. Dielectric studies showed that a high dielectric constant of the nanocomposite was dependent on the ratio of graphene:bariumtitanate: polydimethylsiloxane, showing that ratio of 15:25:100 had a high dielectric constant at high frequency range and the ratio 15:30:100 at the low frequency range. At 2 Hz the ratio 15:30:100 showed a dielectric constant of 116.9 which decreased to 30.6 at 2 MHz, thus showing capacitive nature at full frequency range. Meanwhile dielectric loss was very low i.e., 1.3 at 20 Hz and 0.02 at 2 MHz and AC conductivity was 1.6 × 10−7 S/m. Ferroelectric properties like energy density, energy loss and efficiency were calculated and compared. At an electric field of 0.92 kV/cm, remanant polarization and coercive field were 3.9×10−4 μC/cm2 and15.82 kV/cm, respectively. Energy density of 0.64 J/m3, energy loss 0.358 J/m3 and efficiency 64.2% were confirmed respectively. Results indicate that the nanocomposite films having desirable performances such as flexibility, thermal stability, high dielectric constant, high energy density are good candidates to be considered in energy storage and memory device applications.Item Metadata only Perovskite materials as superior and powerful platforms for energy conversion and storage applications(Elsevier, 2021) Goel, P.; Sundriyal, S.; Shrivastav, V.; Mishra, S.; Dubal, D.P.; Kim, K.H.; Deep, A.In order to meet the continuously growing demand for clean energy, a plethora of advanced materials have been exploited for energy storage applications. Among these materials, perovskites belong to a relatively new family of compounds with the structural formula of ABX3. These compounds exhibit a variety of electrical, optical, and electronic properties to adopt them for a variety of energy conversion and storage applications. The present review highlights the multifaceted nature of perovskite materials by covering a brief background, common crystallographic structures, and the importance of doping with different elements. Our discussion is extended further on the strategic energy applications of perovskites in modern devices such as fuel cells, lithium batteries, supercapacitors, LEDs, and solar cells.Item Metadata only Coupling Natural Halloysite Nanotubes and Bimetallic Pt-Au Alloy Nanoparticles for Highly Efficient and Selective Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid(American Chemical Society, 2022) Zhong, X.; Yuan, P.; Wei, Y.; Liu, D.; Losic, D.; Li, M.The aerobic oxidation of 5-hydroxymethylfurfural (HMF), a key platform compound derived from biomass, to 2,5-furandicarboxylic acid (FDCA) is a highly important reaction in the production of green and sustainable chemicals. Here, we developed a highly efficient and stable halloysite-supported Pt-Au alloy catalyst for the selective oxidation of HMF to FDCA. The catalyst was synthesized through the organosilane functionalization of halloysite nanotubes, followed by the in situ formation and dispersion of Pt-Au alloy nanoparticles on the internal and external surfaces of nanotubes. The composition, morphology, and structure of the prepared catalyst were characterized. The catalyst with the optimal composition of Pt/Au molar ratio of 1/4 and metal loading of 1.5 wt % exhibited outstanding catalytic activity for the oxidation of HMF to FDCA using O2 as an oxidant with 100% conversion of HMF and 99% selectivity of FDCA. This excellent catalytic performance is mainly attributed to the high dispersion and alloying effects of bimetallic nanoparticles, which promoted the activation of reactants or intermediates and further improved FDCA selectivity. Furthermore, the halloysite-supported Pt/Au bimetallic catalyst showed high stability and reusability. This study provides a promising strategy by combining clay mineral halloysite and bimetallic alloys for developing efficient catalysts with high FDCA selectivity and stability for the oxidation of HMF to FDCA.Item Metadata only Magnetic reduced graphene oxide as a nano-vehicle for loading and delivery of curcumin(Elsevier BV, 2021) Zhu, Z.; Zhang, Q.; Yap, P.; Ni, Y.; Losic, D.Abstract not availableItem Metadata only Hybrid shell of MXene and reduced graphene oxide assembled on PMMA bead core towards tunable thermoconductive and EMI shielding nanocomposites(Elsevier, 2021) Vu, M.C.; Mani, D.; Kim, J.B.; Jeong, T.H.; Park, S.; Murali, G.; In, I.; Won, J.C.; Losic, D.; Lim, C.S.; Kim, S.R.Lightweight and multifunctional thermoconductive electromagnetic interference (EMI) shielding nanocomposites with excellent EMI shielding performance and heat dissipation are in high demand for the development of the next generation of highly integrated electronic devices. Herein, a scalable fabrication method for multifunctional nanocomposites with tunable thermal conductivity and superior EMI shielding performance is developed. A hybrid shell of MXene (MX) and reduced graphene oxide (rGO) assembled on poly(methyl methacrylate) (PMMA) beads surface was synthesized and used to prepare a three-dimensional structure of the MXene/rGO in PMMA nanocomposites (MXrGO@PMMA) under hot-compression. The tunable thermal conductivity and EMI SE of MXrGO@PMMA nanocomposites with only 2 vol% of the total fillers content are in the range of 0.98 to 3.96 W⋅m⁻1⋅K⁻ 1 and 28 to 61 dB, respectively, when the volume fraction ratio between MXene and rGO is varied. Additionally, PMMA nanocomposites have been successfully demonstrated as a proof-ofconcept for use as a practical heat-dissipating material.Item Metadata only International interlaboratory comparison of Raman spectroscopic analysis of CVD-grown graphene(IOP Publishing, 2022) Turner, P.; Paton, K.R.; Legge, E.J.; de Luna Bugallo, A.; Rocha-Robledo, A.K.S.; Zahab, A.-A.; Centeno, A.; Sacco, A.; Pesquera, A.; Zurutuza, A.; Rossi, A.M.; Tran, D.N.H.; Silva, D.; Losic, D.; Farivar, F.; Kerdoncuff, H.; Kwon, H.; Pirart, J.; Campos, J.L.E.; Subhedar, K.M.; et al.There is a pressing need for reliable, reproducible and accurate measurements of graphene’s properties, through international standards, to facilitate industrial growth. However, trustworthy and verified standards require rigorous metrological studies, determining, quantifying and reducing the sources of measurement uncertainty. Towards this effort, we report the procedure and the results of an international interlaboratory comparison (ILC) study, conducted under Versailles Project on Advanced Materials and Standards. This ILC focusses on the comparability of Raman spectroscopy measurements of chemical vapour deposition (CVD) grown graphene using the same measurement protocol across different institutes and laboratories. With data gathered from 17 participants across academia, industry (including instrument manufacturers) and national metrology institutes, this study investigates the measurement uncertainty contributions from both Raman spectroscopy measurements and data analysis procedures, as well as provides solutions for improved accuracy and precision. While many of the reported Raman metrics were relatively consistent, significant and meaningful outliers occurred due to differences in the instruments and data analysis. These variations resulted in inconsistent reports of peak intensity ratios, peak widths and the coverage of graphene. Due to a lack of relative intensity calibration, the relative difference reported in the 2D- and G peak intensity ratios (I2D/IG) was up to 200%. It was also shown that the standard deviation for Γ2D values reported by different software packages, was 15× larger for Lorentzian fit functions than for pseudo-Voigt functions. This study has shown that by adopting a relative intensity calibration and consistent peak fitting and data analysis methodologies, these large, and previously unquantified, variations can be significantly reduced, allowing more reproducible and comparable measurements for the graphene community, supporting fundamental research through to the growing graphene industry worldwide. This project and its findings directly underpin the development of the ISO/IEC standard ‘DTS 21356-2—Nanotechnologies—Structural Characterisation of CVD-grown Graphene’.Item Metadata only New insights on energetic properties of graphene oxide (GO) materials and their safety and environmental risks(Elsevier BV, 2022) Losic, D.; Farivar, F.; Yap, P.L.; Tung, T.T.; Nine, M.J.Graphene oxide (GO) has been recognized as a thermally unstable and energetic material, but surprisingly its environmental and safety risks were not fully explored, defined, and regulated. In this study, systematic explosivity and flammability characterizations of commercial GO materials were conducted to evaluate the influence of key parameters such as physical forms (paste, powders, films, and aerogels), temperature, heating rate, mass, and heating environment, as well as their potential safety and environmental impacts. Results based on thermogravimetric analysis (TGA) showed that GO in paste and powder forms have lower temperature thresholds (>180-192 °C) to initiate micro-explosions compared to GO film and aerogels (> 205 °C and 213 °C) regardless of the environment (inert, air, or oxygen). The observed explosive behavior can be explained by thermal runaway reactions as a result of thermal deoxygenation and decomposition of oxygen functional groups. Flammability rating and limiting oxygen index (LOI) results confirmed that GO films are flammable materials that can spontaneously propagate flame in a low oxygen environment (~11 %). These results provided new insights about potential safety and environmental risks of GO materials, which somehow were not considered, suggesting urgent actions to improve current safety protocols for labeling, handling, transporting, and storage practices from manufacturers to the end-users.Item Metadata only Rheology of edible food inks from 2D/3D/4D printing, and its role in future 5D/6D printing(Elsevier, 2022) Cheng, Y.; Fu, Y.; Ma, L.; Yap, P.L.; Losic, D.; Wang, H.; Zhang, Y.Food printing involving 2D, 3D, 4D and 5D printing methods has attracted extensive attention owing to the growing living standards and higher consumer demand for innovative food. Printable biopolymers with a special structure hierarchy are particularly appealing to formulate edible inks for food printing as they serve as essential structural components for constructing ink matrix and providing a supportive presence for the printed functions. Rheology (e.g., viscosity, yield stress, temperature ramp & sweep, oscillatory modulus, creep-recovery and thixotropy by methodology including rotation tests, oscillatory tests and mathematic rheological models) is important to redefine the relationship between edible inks and printability. It is essential to promote the practical mass food printing application with high consumer acceptance. The rheological principles of edible inks that underpin a variety of printing techniques are discussed systematically including flowability, shearing dependence, thermal endurability and structure maintainability for pre-evaluating the potential printing effectiveness. The related rheology models indicate the capacity to further deepen the link between ink structure and printing efficiency for printing multi-functional food products. It is found that rheology lays the foundation for design, development and food application of edible food ink printing. This review also summarizes recent advances in 2D/3D/4D/5D printing of rheologically-stable inks in food application, including food decoration, food customization and food intelligence. Additionally, prospects (like 6D printing) and key challenges (rheology with multidisciplinary integration) for edible ink printing are proposed and addressed for creative food production.Item Metadata only Insecticidal effect of graphene against three stored-product beetle species on wheat(Elsevier, 2022) Moisidis, I.C.; Sakka, M.K.; Karunagaran, R.; Losic, D.; Athanassiou, C.G.The efficacy of two formulations of graphene powders against Rhyzopertha dominica (F.), Sitophilus oryzae (L.) and Tribolium castaneum (Herbst) was tested on wheat. The graphene formulations using two different graphene materials were tested at different concentrations, i.e. 0, 250, 500 and 1000 ppm. Adult mortality was recorded after 7, 14 and 21 days of exposure and progeny production was recorded after 65 days. Our results indicate that the increase of concentration increased adult mortality and decreased progeny production. Both graphene formulations showed similar results. Rhyzopertha dominica and S. oryzae were found to be the most susceptible species with 100% mortality after 21 days of exposure to 250 ppm. Application of 500 and 1000 ppm caused 100% mortality after 7 days of exposure. In contrast, for T. castaneum some survival was recorded after 7 days of exposure at 500 and 1000 ppm, but mortality was 100% at the 21-day exposure interval. For both formulations, progeny production was negligibly reduced at the two highest graphene concentrations. The findings of the present research showed that the graphene materials showed high efficacy, especially at 500 and 1000 ppm, and could be used to control the species tested and indicated graphene insecticidal properties most likely are based on a physical mode of action.Item Metadata only Laminated antimonene as an alternative and efficient shielding strategy against X-ray radiation(Elsevier, 2022) Nine, M.J.; Yu, L.; Pereira, A.L.C.; Batmunkh, M.; Hassan, K.; Santos, A.M.C.; Tung, T.T.; Losic, D.Scientific research concerning lead (Pb)-free shielding materials and their composites showed great promise in shielding ionising radiation (e.g., X-ray, gamma-ray) applied in medical diagnosis, security screening, space and nuclear industry. However, the typical “blend and mix” composites with imperfect composition due to random particle distribution, morphology, low density, and unwanted micro-crack in an inappropriate matrix could result in poor X-ray attenuation. To address these limitations, we demonstrate a unique laminated architecture using few-layered antimonene (SbFL) to increase the chances of interaction between ionising radiation and shielding materials. The proposed lamination is a sandwiched structure (PDMS-SbFL-PDMS) having an identical composition to a conventional form of composite (PDMS/SbFL). The experiments were carried out within X-ray energy ranging between ~14 and 35 keV (equivalent tube voltage of 30 to 100 kVp), which was further numerically investigated with an extended energy range up to 100 keV. The PDMS-laminated SbFL with a cotton carrier exhibited an attenuation enhancement of 45% and ~3 times reduced half-value layers (HVL) at high energy (e.g., ~35 keV) X-ray compared to the conventional PDMS/SbFL composite (13.5 wt% of SbFL). Using high-density SbFL nanoflakes in a sandwiched structure demonstrated significant potential to overcome practical challenges (e.g., aggregation, particle distribution, interparticle gaps, cracks) of composites typically employed for shielding ionising radiation.Item Metadata only Rational design for the microplasma synthesis from vitamin B9 to N-doped carbon quantum dots towards selected applications(Elsevier, 2022) Pho, Q.H.; Lin, L.L.; Tran, N.N.; Tran, T.T.; Nguyen, A.H.; Losic, D.; Rebrov, E.V.; Hessel, V.N-doped carbon quantum dots (NCQD) are rationally designed and synthesised, for the first time, from folic acid (Vitamin B9) by a non-thermal microplasma jet. A new conceptual design was developed to synthesise the desirable NCQD for three main applications (nanopesticides, water purification, and theranostic treatment). The structural and analytical characterisation confirmed an average size of 3.1 nm for the synthesised NCQD with the multi-functional groups (-OH, –COOH, –NH2) on their surface. The TEM results indicated that the core of NCQD was a multilayered structure, including single defected graphene sheets of graphitic-nitrogen and pyrrolicnitrogen. In addition, fluorescence performance and stability of the as-prepared NCQD were determined. The quantum yield of NCQD was 35%, which is relatively high, with a strong blue fluorescence. A basis for predicting colloidal behaviours based on balancing molecular attractive and repulsive forces was elucidated by applying the Derjaguin, Landau, Vervey, and Overbeek (DLVO) theory. Finally, compared with other similar microplasmaassisted synthesis processes, this developed method has proven the ability to provide a tailored and scalable synthesis process of high-quantum-yield NCQD at gram-scale production.Item Metadata only One step strategy for reduced graphene oxide/cobalt-iron oxide/polypyrrole nanocomposite preparation for high performance supercapacitor electrodes(Elsevier, 2022) Ishaq, S.; Moussa, M.; Kanwal, F.; Ayub, R.; Van, T.N.; Azhar, U.; Losic, D.Supercapacitors are crucial energy generating devices due to profound characteristics namely high specific capacitance, rapid charge storing capability, high discharge time, and environmentally friendly nature. Supercapacitors have high power density but they have demerits of low energy density; usually less than 10 Whkg−1, which needs to be improved to make supercapacitors excellent energy storage devices. Aim of the present research was to fabricate supercapacitor electrodes with high energy density. To achieve these goals herein is presented a simple one step strategy to synthesize binary composite of reduced graphene oxide (rGO) and cobalt-iron oxide (rGO/CoFe2O4) using urea. Urea is used not only to reduced GO but also assist in formation of cobalt-iron oxide from its reactants thus forming binary rGO/CoFe2O4 nanocomposite which was further used to make electrodes for supercapacitors. Synthesized rGO/CoFe2O4 electrode exhibited gravimetric capacitance of 97 Fg−1 while areal capacitance was 165 mFcm−2, when measured at 5 mVs−1. To further enhance electrochemical performance a ternary composite namely reduced graphene oxide/cobalt-iron oxide/polypyrrole (rGO/CoFe2O4/PPy) was synthesized by adding polypyrrole (PPy). Both gravimetric and areal capacitances of the rGO/CoFe2O4/PPy were improved to 164 Fg−1 and 279 mFcm−2, respectively. Specific energy and specific power of our synthesized ternary rGO/CoFe2O4/PPy nanocomposite were 22.8 Whkg−1 and 410 Wkg−1, respectively. Results from this study showed a simple fabrication method of binary and ternary nanocomposites and synergistic influence of participating components on electrode performance for supercapacitors exhibiting high gravimetric and areal capacitances, as well as high energy and power densities.Item Metadata only Coupled dynamics of double beams reinforced with bidirectional functionally graded carbon nanotubes(Elsevier, 2022) Ong, O.Z.S.; Ghayesh, M.H.; Losic, D.; Amabili, M.The coupled dynamics of a double beam system connected via an elastic layer is investigated. The double beam is reinforced with bidirectional functionally graded carbon nanotubes. Independent transverse and axial motions for each beam, as well as their couplings, are considered in the model. The two interconnected beams are functionally graded with patterns of UD, FGV, FGO, and FGX in the thickness direction, and a power-law function in the longitudinal direction, and a power-law function in both the thickness and longitudinal directions. The results suggested that increasing the carbon nanotube volume fraction in the thickness or length or both the directions of the two beams leads to an increase in both series of the axial and transverse natural frequencies. The study also identifies that when the double beams are reinforced with UD, FGO, or FGX patterns, with the same volume fraction, which are symmetrical about the transverse axis, they possess the same axial natural frequencies. It is also revealed that increasing the stiffness of the elastic layer place in-between the two beams, causes an increase in the second series of the transverse natural frequency, for all cases, whether it is reinforced by carbon nanotube in the thickness or in the length or in both thickness and length directions of the beams. These results will form crucial considerations when designing double beam systems to improve reliability and safety.Item Metadata only Coupling graphene microribbons with carbon nanofibers: New carbon hybrids for high-performing lithium and potassium-ion batteries(Elsevier BV, 2022) Tung, T.T.; Moussa, M.; Tripathi, K.M.; Kim, T.Y.; Nine, M.J.; Nanjundan, A.K.; Dubal, D.; Losic, D.Carbon‑carbon allotropic hybrids exhibit remarkable properties, including exceptional electrochemical charge storage capacities. A novel hybrid material composed of 1D carbon nanofibers (CNF) and 2D graphene micro-ribbons (GMR) was synthesized and incorporated as anodes in Li-ion batteries (LIB) and Potassium-ion batteries (KIB) for improved storage capacity. CNF-GMR material was hybridized simultaneously by one-step chemical vapour deposition (CVD) synthetic process, wherein the CNF were grown on the graphene surface using an iron oxide catalyst. Meanwhile, the GMRs were formed by the catalytic cutting of few-layer graphene. This unique carbon‑carbon allotropic hybrid exhibits excellent structural integrity, good electrical conductivity (718 S/m) and high specific surface area (305.6 g/m2). The as-prepared materials, when used as an anode in batteries, exhibited a highly reversible capacity (598 mAhg−1 and 410 mAhg−1 at 0.10 Ag−1 for LIB and KIB, respectively) with fast charging and discharging capability, and long-term cycling stability with 99% Coulombic efficiency over 1000 cycles.Item Metadata only Graphene-based multifunctional surface and structure gradients engineered by atmospheric plasma(Elsevier BV, 2022) Alosaimi, F.K.; Tung, T.T.; Dao, V.D.; Huyen, N.K.; Nine, M.J.; Hassan, K.; Ma, J.; Losic, D.Surface and structure gradients are ubiquitous in nature, where gradual changes in physical, chemical, mechanical and other properties of biomaterial are generated aiming to achieve intricate biological functions. These bioinspired gradients have been explored and fabricated using different materials in small scales (nm or µm) and usually with single function. Leveraging an outstanding property of graphene and their multi functionality, this paper presents a demonstration of the surface and structure gradients with gradual change of multiple functionalities such as structure, chemistry, wettability, charge, electrical and thermal conductivity in all three dimensions (1D, 2D and 3D). These multifunctional and multidimensional gradients with a gradual transition from graphene oxide (GO) to partially reduced GO (prGO) and reduced GO (rGO) were created by atmospheric plasma treatment of GO substrates (films and foams) using non-uniform exposure of plasma beams. The plasma beams with controllable energy, asymmetric contact exposure and timing were used to generate a gradual chemical reduction of oxygen groups and GO to prGO and rGO and fabricate the sizable (cm) range surface and 3D gradients with gradual change of multiple functionalities. This simple and low-cost method is a powerful and straightforward strategy to produce multifunctional gradients with 1D, 2D and 3D structures in different forms (films, foams) on variety of substrates (metals, semiconductors, glass,plastics, textile, etc.). Practical application of fabricated gradients is successfully demonstrated as absorbers for solar-driven water evaporation showing excellent water evaporation rates results for 1 sun irradiation of 1.782 kg•m−2•h−1 and the net solar to steam efficiencies of 97%. These gradients are very useful for diverse fundamental and practical applications, and one elegant example of efficient solar-driven water evaporation was demonstrated.Item Metadata only 3D printing interface-modified PDMS/MXene nanocomposites for stretchable conductors(Elsevier, 2022) Aakyiir, M.; Tanner, B.; Yap, P.L.; Rastin, H.; Tung, T.T.; Losic, D.; Meng, Q.; Ma, J.Additive manufacturing has rapidly evolved over recent years with the advent of polymer inks and those inks containing novel nanomaterials. The compatibility of polymer inks with nanomaterial inks remains a great challenge. Simple yet effective methods for interface improvement are highly sought-after to significantly enhance the functional and mechanical properties of printed polymer nanocomposites. In this study, we developed and modified a Ti3C2 MXene ink with a siloxane surfactant to provide compatibility with a polydimethylsiloxane (PDMS) matrix. The rheology of all the inks was investigated with parameters such as complex modulus and viscosity, confirming a self-supporting ink behaviour, whilst Fourier-transform infrared spectroscopy exposed the inks’ reaction mechanisms. The modified MXene nanosheets have displayed strong interactions with PDMS over a wide strain amplitude. An electrical conductivity of 6.14 × 10−2 S cm−1 was recorded for a stretchable nanocomposite conductor containing the modified MXene ink. The nanocomposite revealed a nearly linear stress-strain relationship and a maximum stress of 0.25 MPa. Within 5% strain, the relative resistance change remained below 35% for up to 100 cycles, suggesting high flexibility, conductivity and mechanical resilience. This study creates a pathway for 3D printing conductive polymer/nanomaterial inks for multifunctional applications such as stretchable electronics and sensors.Item Metadata only Tuning the Hierarchical Structure and Resilience of Resilin-like Polypeptide Hydrogels Using Graphene Oxide(American Chemical Society (ACS), 2020) Balu, R.; Dorishetty, P.; Mata, J.P.; Hill, A.J.; Dutta, N.K.; Choudhury, N.R.Resilin-like polypeptides (RLPs) are an important class of intrinsically disordered multistimuli-responsive bioelastomers. The nanostructure of RLPs in solution has been extensively studied in the past few years, from dilute to molecular crowding conditions, and with the addition of rigid biopolymers. Modification of the hierarchical network structure of RLP hydrogels using graphene oxide (GO) as an additive is a burgeoning prospect for their application in the bioelectronic and biomedical fields. In this work, we systemically study the influence of incorporating GO into RLP (Rec1) hydrogels for tuning their physicochemical properties and understanding the gel−cell interactions. The nature of GO interaction with the Rec1 hydrogel is deduced from the change in structure and properties. Contrast-matching small-angle and ultra-small-angle neutron-scattering techniques were used to investigate the network structure of the Rec1 hydrogel and how this structure is modified in the presence of GO. Incorporation of GO in the Rec1 hydrogel matrix results in an increase in the micromechanical resilience, equilibrium water swelling ratio, micropore size, cross-linked domain size; with a decrease in the cross-link density, mass fractal cluster size, local compressive elastic modulus, and cell inert characteristics. These property combinations achieved with the addition of GO further open up the available structure−property design window for RLP applications.