Effect of Particle Size on the Mechanical Properties of TiO2–Epoxy Nanocomposites

This study investigated the effects of the packing density and particle size distribution of TiO₂ nanoparticles on the mechanical properties of TiO₂–epoxy nanocomposites (NCs). The uniform dispersion and good interfacial bonding of TiO₂ in the epoxy resin resulted in improved mechanical properties with the addition of nanoparticles. Reinforcement nano-TiO₂ particles dispersed in deionized water produced by three different ultrasonic dispersion methods were used; the ultrasonication effects were then compared. The nano-TiO₂ suspension was added at 0.5–5.0 wt.%, and the mechanical and thermal properties of TiO₂–epoxy NCs were compared using a universal testing machine, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and differential scanning calorimetry (DSC). The tensile strength of the NCs was improved by the dispersion strengthening effect of the TiO₂ nanoparticles, and focused sonication improved the tensile strength the most when nano-TiO₂ suspensions with a particle size of 100 nm or smaller were used. Thus, the reinforcing effect of TiO₂ nanoparticles on the epoxy resin was observed, and the nano-TiO₂ suspension produced by focused sonication showed a more distinct reinforcing effect.     

Improved Thermo-Mechanical Properties and Reduced Hydrogen Permeation of Short Side-Chain Perfluorosulfonic Acid Membranes Doped with Ti3C2Tx

Benefiting from its large specific surface with functional -OH/-F groups, Ti₃C₂T_x, a typical two-dimensional (2D) material in the recently developed MXene family, was synthesized and used as a filler to improve the properties of the short side-chain (SSC) perfluorosulfonic acid (PFSA) proton exchange membrane. It is found that the proton conductivity is enhanced by 15% while the hydrogen permeation is reduced by 45% after the addition of 1.5 wt% Ti₃C₂T_x filler into the SSC PFSA membrane. The improved proton conductivity of the composite membrane could be associated with the improved proton transport environment in the presence of the hydrophilic functional groups (such as -OH) of the Ti₃C₂T_x filler. The significantly reduced hydrogen permeation could be attributed to the incorporation of the impermeable Ti₃C₂T_x 2D fillers and the decreased hydrophilic ionic domain spacing examined by the small angle X-ray scattering (SAXS) for the composite membrane. Furthermore, improved thermo-mechanical properties of the SSC/Ti₃C₂T_x composite membrane were measured by dynamic mechanical analyzer (DMA) and tensile strength testing. The demonstrated higher proton conductivity, lower hydrogen permeation, and improved thermo-mechanical stability indicate that the SSC/Ti₃C₂T_x composite membranes could be a potential membrane material for PEM fuel cells operating above the water boiling temperature.     

Microstructure and Mechanical Properties of Alumina Composites with Addition of Structurally Modified 2D Ti3C2 (MXene) Phase

This study presents new findings related to the incorporation of MXene phases into ceramic. Aluminium oxide and synthesised Ti₃C₂ were utilised as starting materials. Knowing the tendency of MXenes to oxidation and degradation, particularly at higher temperatures, structural modifications were proposed. They consisted of creating the metallic layer on the Ti₃C₂, by sputtering the titanium or molybdenum. To prepare the composites, powder metallurgy and spark plasma sintering (SPS) techniques were adopted. In order to evaluate the effectiveness of the applied modifications, the emphasis of the research was placed on microstructural analysis. In addition, the mechanical properties of the obtained sinters were examined. Observations revealed significant changes in the MXenes degradation process, from porous areas with TiC particles (for unmodified Ti₃C₂), to in situ creation of graphitic carbon (in the case of Ti₃C₂-Ti/Mo). Moreover, the fracture changed from purely intergranular to cracking with high participation of transgranular mode, analogously. In addition, the results obtained showed an improvement in the mechanical properties for composites with Ti/Mo modifications (an increase of 10% and 15% in hardness and fracture toughness respectively, for specimens with 0.5 wt.% Ti₃C₂-Mo). For unmodified Ti₃C₂, enormously cracked areas with spatters emerged during tests, making the measurements impossible to perform.     

Jujube Shell Based-Porous Carbon Composites Double-Doped by MnO2 and Ti3C2Tx: The Effect of Double Pseudocapacitive Doping on Electrochemical Properties

In this study, manganese-containing porous carbon was synthesized from jujube shells by two-step carbonization and activation and was then covered with Ti₃C₂Tx to obtain double-doped biomass composites. In order to improve the interfacial properties (surface tension and wettability) between Ti₃C₂Tx and porous carbon, the effects of two media (deionized water and acetone solution) on the electrochemical properties of the composites were compared. The acetone solution changed the surface rheology of Ti₃C₂Tx and porous carbon, and the decreased surface tension and the increased wettability contributed to the ordered growth of 2D-Ti₃C₂Tx on the surface of the porous carbon. Raman analysis shows the relatively higher graphitization degree of JSPC&Ti₃C₂Tx (acetone). Compared with JSPC&Ti₃C₂Tx, JSPC&Ti₃C₂Tx (acetone) can maintain better rectangle-like properties even at a higher scanning rate. Under the effect of the acetone solution, the pseudocapacitive ratio of JSPC&Ti₃C₂Tx (acetone) increased from 10.1% to 30.7%. At the current density of 0.5 A/g, the specific capacitance of JSPC&Ti₃C₂Tx (acetone) achieved 96.83 F/g, and the specific capacitance of 58.17 F/g was maintained even at the high current density (10 A/g), which shows excellent magnification. Under the condition of the current density of 10 A/g, JSPC&Ti₃C₂Tx (acetone) can obtain a power density of 52,000 W/kg while maintaining an energy density of 8.74 Wh/kg. After 2000 cycles, the symmetrical button battery assembled with this material can still have a capacitance retention rate of more than 90%. This method realized the deep utilization of green and low-cost raw materials by using biomass as the precursor of composite materials and promoted the further development of carbon-based supercapacitor electrode materials.     

Microstructure and Tribological Properties of Spark-Plasma-Sintered Ti3SiC2-Pb-Ag Composites at Elevated Temperatures

Ti₃SiC₂-PbO-Ag composites (TSC-PA) were successfully prepared using the spark plasma sintering (SPS) technique. The ingredient and morphology of the as-synthesized composites were elaborately investigated. The tribological properties of the TSC-PA pin sliding against Inconel 718 alloys disk at room temperature (RT) to 800 °C were examined in air. The wear mechanisms were argued elaborately. The results showed that the TSC-PA was mainly composed of Ti₃SiC₂, Pb, and Ag. The average friction coefficient of TSC-PA gradually decreased from 0.72 (RT) to 0.3 (800 °C), with the temperature increasing from RT to 800 °C. The wear rate of TSC-PA showed a decreasing trend, with the temperature rising from RT to 800 °C. The wear rate of Inconel 718 exhibited positive wear at RT and negative wear at elevated temperatures. The tribological property of TSC-PA was related to the tribo-chemistry, and the abrasive and adhesive wear.     

Tribo-oxide Competition and Oxide Layer Formation of Ti3SiC2/CaF2 Self-Lubricating Composites during the Friction Process in a Wide Temperature Range

Ti₃SiC₂/CaF₂ composites were prepared by the spark plasma sintering (SPS) process. Both the microstructure of Ti₃SiC₂/CaF₂ and the influence of test temperature on the tribological behavior of the Ti₃SiC₂/CaF₂ composites were investigated. The synergistic effect of friction and oxidation was evaluated by analyzing the worn surface morphology. The results showed that Ti₃SiC₂/CaF₂ were still brittle materials after adding CaF₂, which was in agreement with Ti₃SiC₂. The hardness, relative density, flexural strength and compressive strength of the Ti₃SiC₂/CaF₂ composites were slightly lower than those of Ti₃SiC₂, and the addition of CaF₂ decreased the decomposition temperature of Ti₃SiC₂ from 1350 to 1300 °C. Simultaneously, as the temperature of the test increased, the friction coefficient of Ti₃SiC₂/CaF₂ showed a downward trend (from 0.81 to 0.34), and its the wear rate was insensitive.     

Microstructure and Mechanical Properties of Composites Obtained by Spark Plasma Sintering of Ti3SiC2-15 vol.%Cu Mixtures

Method of soft metal (Cu) strengthening of Ti₃SiC₂ was conducted to increase the hardness and improve the wear resistance of Ti₃SiC₂. Ti₃SiC₂/Cu composites containing 15 vol.% Cu were fabricated by Spark Plasma Sintering (SPS) in a vacuum. The effect of the sintering temperature on the phase composition, microstructure and mechanical properties of the composites was investigated in detail. The as-synthesized composites were thoroughly characterized by scanning electron micrography (SEM), optical micrography (OM) and X-ray diffractometry (XRD), respectively. The results indicated that the constituent of the Ti₃SiC₂/Cu composites sintered at different temperatures included Ti₃SiC₂, Cu₃Si and TiC. The formation of Cu₃Si and TiC originated from the reaction between Ti₃SiC₂ and Cu, which was induced by the presence of Cu and the de-intercalation of Si atoms Ti₃SiC₂. OM analysis showed that with the increase in the sintering temperature, the reaction between Ti₃SiC₂ and Cu was severe, leading to the Ti₃SiC₂ getting smaller and smaller. SEM measurements illustrated that the uniformity of the microstructure distribution of the composites was restricted by the agglomeration of Cu, controlling the mechanical behaviors of the composites. At 1000 °C, the distribution of Cu in the composites was relatively even; thus, the composites exhibited the highest density, relatively high hardness and compressive strength. The relationships of the temperature, the current and the axial dimension with the time during the sintering process were further discussed. Additionally, a schematic illustration was proposed to explain the related sintering characteristic of the composites sintered by SPS. The as-synthesized Ti₃SiC₂/Cu composites were expected to improve the wear resistance of polycrystalline Ti₃SiC₂.     

Synthesis and Tribological Characterization of Ti3SiC2/ZnO Composites

Dense Ti₃SiC₂/ZnO composites were sintered at different temperatures by spark plasma sintering (SPS). The effects of sintering temperature on composition and mechanical properties of Ti₃SiC₂/ZnO composites were studied. The tribological behaviors of Ti₃SiC₂/ZnO composites/Inconel 718 alloy tribo-pairs at elevated temperature from 25 °C to 800 °C were discussed. The experimental results showed that the initial decomposition temperature of the Ti₃SiC₂/ZnO composite was 1150 °C, and Ti₃SiC₂ decomposed into TiC. When the decomposition temperature was higher than 1150 °C, the compositions of the Ti₃SiC₂/ZnO composites were Ti₃SiC₂, ZnO, and TiC. It was found that Ti₃SiC₂/ZnO composites had better self-lubricating performance than Ti₃SiC₂ at elevated temperature from 600 °C to 800 °C, which was owing to material transfers of tribo-pairs and sheared oxides generated by tribo-oxidation reactions.     

Influence of MXene (Ti3C2) Phase Addition on the Microstructure and Mechanical Properties of Silicon Nitride Ceramics

This paper discusses the influence of Ti₃C₂ (MXene) addition on silicon nitride and its impact on the microstructure and mechanical properties of the latter. Composites were prepared through powder processing and sintered using the spark plasma sintering (SPS) technic. Relative density, hardness and fracture toughness, were analyzed. The highest fracture toughness at 5.3 MPa·m^1/2 and the highest hardness at HV5 2217 were achieved for 0.7 and 2 wt.% Ti₃C₂, respectively. Moreover, the formation of the Si₂N₂O phase was observed as a result of both the MXene addition and the preservation of the α-Si₃N₄→β-Si₃N₄ phase transformation during the sintering process.     

Assessment of Tribological Properties of Ti3C2 as a Water-Based Lubricant Additive

Water-based lubrication has attracted remarkable interest due to its environmental and economic advantages. However, practical applications of water-based lubrication are often limited, mainly because of low viscosity and corrosivity. The use of additives has been proposed to overcome these limitations. In this work, the tribological characteristics of titanium carbide (Ti₃C₂) MXenes, as additives for water-based lubrication, were systematically investigated for contact sliding between stainless steel under various normal forces and Ti₃C₂ concentrations. Both friction and wear were found to decrease with increasing Ti₃C₂ concentration up to 5 wt%, and then increased when the concentration was larger than 5 wt%. The results suggest that Ti₃C₂ flakes hindered direct contact, particularly at the edges of the contact interfaces. It was further shown that the agglomeration of Ti₃C₂ flakes may have reduced the hindering when an excessive amount of Ti₃C₂ (e.g., 7 wt%) was applied. The decreases in the friction coefficient and wear rate with 5 wt% of Ti₃C₂ concentration w approximately 20% and 48%, respectively. The outcomes of this work may be helpful in gaining a better understanding of the tribological properties of Ti₃C₂ as a feasible water-based lubrication additive.     

3D Porous MXene (Ti3C2Tx) Prepared by Alkaline-Induced Flocculation for Supercapacitor Electrodes

2D layered MXene (Ti₃C₂T_x) with high conductivity and pseudo-capacitance properties presents great application potential with regard to electrode materials for supercapacitors. However, the self-restacking and agglomeration phenomenon between Ti₃C₂T_x layers retards ion transfer and limits electrochemical performance improvement. In this study, a 3D porous structure of Ti₃C₂T_x was obtained by adding alkali to a Ti₃C₂T_x colloid, which was followed by flocculation. Alkaline-induced flocculation is simple and effective, can be completed within minutes, and provides 3D porous networks. As 3D porous network structures present larger surface areas and more active sites, ions transfer accelerates, which is crucial with regard to the improvement of the superior capacitance and rate performance of electrodes. The sample processed with KOH (K-a-Ti₃C₂T_x) exhibited a high capacity of approximately 300.2 F g⁻¹ at the current density of 1 A g⁻¹. The capacitance of the samples treated with NaOH and LiOH is low. In addition, annealing is essential to further improve the capacitive performance of Ti₃C₂T_x. After annealing at 400 °C for 2 h in a vacuum tube furnace, the sample treated with KOH (K-A-Ti₃C₂T_x) exhibited an excellent specific capacitance of approximately 400.7 F g⁻¹ at a current density of 1 A g⁻¹, which is considerably higher than that of pristine Ti₃C₂T_x (228.2 F g⁻¹). Furthermore, after 5000 charge–discharge cycles, the capacitance retention rate reached 89%. This result can be attributed to annealing, which can further remove unfavourable surface groups, such as –F or –Cl, and then improve conductivity capacitance and rate performance. This study can provide an effective approach to the preparation of high-performance supercapacitor electrode materials.     

Effect of Ti3SiC2 and Ti3AlC2 Particles on Microstructure and Wear Resistance of Microarc Oxidation Layers on TC4 Alloy

Microarc oxidation (MAO) layers were prepared using 8g/L Na₂SiO₃ + 6g/L (NaPO₃)₆ + 4g/L Na₂WO₄ electrolyte with the addition of 2g/L Ti₃SiC₂/Ti₃AlC₂ particles under constant-current mode. The roughness, porosity, composition, surface/cross-sectional morphology, and frictional behavior of the prepared MAO layers were characterized by 3D real-color electron microscopy, scanning electron microscopy, X-ray energy spectrometry, X-ray diffractometry, and with a tribo-tester. The results showed that the addition of Ti₃SiC₂ and Ti₃AlC₂ to the electrolyte reduced the porosity of the prepared layers by 9% compared with that of the MAO layer without added particles. The addition of Ti₃SiC₂/Ti₃AlC₂ also reduced the friction coefficient and wear rate of the prepared layers by 35% compared with that of the MAO layer without added particles. It was found that the addition of Ti₃AlC₂ particles to the electrolyte resulted in the lowest porosity and the lowest wear volume.     

Construction of 0D/2D Schottky Heterojunctions of ZnO and Ti3C2 Nanosheets with the Enriched Transfer of Interfacial Charges for Photocatalytic Hydrogen Evolution

The development of cost-effective co-catalysts of high photocatalytic activity and recyclability is still a challenge in the energy transformation domain. In this study, 0D/2D Schottky heterojunctions, consisting of 0D ZnO and 2D Ti₃C₂, were successfully synthesized by the electrostatic self-assembling of ZnO nanoparticles on Ti₃C₂ nanosheets. In constructing these heterojunctions, Ti₃C₂ nanosheets acted as a co-catalyst for enhancing the transfer of excitons and their separation to support the photocatalytic response of ZnO. The as-prepared ZnO/Ti₃C₂ composites demonstrate an abbreviated charge transit channel, a huge interfacial contact area and the interfacial electrons’ transport potential. The extended optical response and large reactive area of the ZnO/Ti₃C₂ composite promoted the formation of excitons and reactive sites on the photocatalyst’s surface. The ZnO/Ti₃C₂ Schottky heterojunction showed significantly high photocatalytic activity for hydrogen production from a water–ethanol solution under the light illumination in the visible region. The hydrogen evolution overoptimized the ZnO/Ti₃C₂ composition with 30 wt.% of Ti₃C₂, which was eight times higher than the pristine ZnO. These findings can be helpful in developing 0D/2D heterojunction systems for photocatalytic applications by utilizing Ti₃C₂ as a low-cost co-catalyst.     

Microstructure and Properties of TiB2 Composites Produced by Spark Plasma Sintering with the Addition of Ti5Si3

Titanium diboride (TiB₂) is a hard, refractory material, attractive for a number of applications, including wear-resistant machine parts and tools, but it is difficult to densify. The spark plasma sintering (SPS) method allows producing TiB₂-based composites of high density with different sintering aids, among them titanium silicides. In this paper, Ti₅Si₃ is used as a sintering aid for the sintering of TiB₂/10 wt % Ti₅Si₃ and TiB₂/20 wt % Ti₅Si₃ composites at 1600 °C and 1700 °C for 10 min. The phase composition of the initial powders and produced composites was analyzed by the X-ray diffraction method using CuK_α radiation. The microstructure was examined using scanning electron microscopy, accompanied by energy-dispersive spectroscopy (EDS). The hardness was determined using a diamond indenter of Vickers geometry loaded at 9.81 N. Friction–wear properties were tested in the dry sliding test in a ball-on-disc configuration, using WC as a counterpart material. The major phases present in the TiB₂/Ti₅Si₃ composites were TiB₂ and Ti₅Si_3. Traces of TiC were also identified. The hardness of the TiB₂/Ti₅Si₃ composites was in the range of 1860–2056 HV1 and decreased with Ti₅Si₃ content, as well as the specific wear rate W_v. The coefficient of friction for the composites was in the range of 0.5–0.54, almost the same as for TiB₂ sinters. The main mechanism of wear was abrasive.     

Electrochemical Mechanism of Molten Salt Electrolysis from TiO2 to Titanium

Electrochemical mechanisms of molten salt electrolysis from TiO₂ to titanium were investigated by Potentiostatic electrolysis, cyclic voltammetry, and square wave voltammetry in NaCl-CaCl₂ at 800 °C. The composition and morphology of the product obtained at different electrolysis times were characterized by XRD and SEM. CaTiO₃ phase was found in the TiO₂ electrochemical reduction process. Electrochemical reduction of TiO₂ to titanium is a four-step reduction process, which can be summarized as TiO₂→Ti₄O₇→Ti₂O₃→TiO→Ti. Spontaneous and electrochemical reactions take place simultaneously in the reduction process. The electrochemical reduction of TiO₂→Ti₄O₇→Ti₂O₃→TiO affected by diffusion was irreversible.     

First Principles Investigation of Binary Chromium Carbides Cr7C3, Cr3C2 and Cr23C6: Electronic Structures,Mechanical Properties and Thermodynamic Properties under Pressure

Binary chromium carbides display excellent wear resistance, extreme stiffness and oxidation resistance under high temperature. The influence of applied pressure on electronic structure, elastic behavior, Debye temperature and hardness of Cr₇C₃, Cr₃C₂ and Cr₂₃C₆ have been investigated by the density functional theory (DFT) method. The results reveal that lattice parameters and formation enthalpy display an inverse relationship with applied pressure, and Cr₃C₂ exhibited optimal structural stability. Moreover, Cr-C orbital hybridization tends to be stronger due to the decreased partial density of states (PDOS) of the Cr atom. The difference in electronic distribution of binary carbides has also been investigated, which confirmed that overall orbital hybridization and covalent characteristics has been enhanced. The theoretical hardness was elevated according to the higher bond strength and bond density. In accordance with structural stability data, Cr₃C₂ has shown maximum theoretical hardness. Furthermore, the anisotropic nature of hardness has been evaluated with external pressure. Cr₃C₂, and the highest isotropic hardness behavior along with an increase in hardness values with increasing pressure has been observed. In addition, the variation in Debye temperatures of binary chromium carbides under applied pressure has also been predicted. The results provide a theoretical insight into electronic, mechanical and thermodynamic behavior of three binary chromium carbides and show the potential of these novel carbides in a wide range of applications.     

Influence of Ti3C2Tx MXene and Surface-Modified Ti3C2Tx MXene Addition on Microstructure and Mechanical Properties of Silicon Carbide Composites Sintered via Spark Plasma Sintering Method

This article presents new findings related to the problem of the introduction of MXene phases into the silicon carbide matrix. The addition of MXene phases, as shown by the latest research, can significantly improve the mechanical properties of silicon carbide, including fracture toughness. Low fracture toughness is one of the main disadvantages that significantly limit its use. As a part of the experiment, two series of composites were produced with the addition of 2D-Ti₃C₂T_x MXene and 2D-Ti₃C₂T_x surface-modified MXene with the use of the sol-gel method with a mixture of Y₂O₃/Al₂O₃ oxides. The composites were obtained with the powder metallurgy technique and sintered with the Spark Plasma Sintering method at 1900 °C. The effect adding MXene phases had on the mechanical properties and microstructure of the produced sinters was investigated. Moreover, the influence of the performed surface modification on changes in the properties of the produced composites was determined. The analysis of the obtained results showed that during sintering, the MXene phases oxidize with the formation of carbon flakes playing the role of reinforcement. The influence of the Y₂O₃/Al₂O₃ layer on the structure of carbon flakes and the higher quality of the interface was also demonstrated. This was reflected in the higher mechanical properties of composites with the addition of modified Ti₃C₂T_x. Composites with 1 wt.% addition of Ti₃C₂T_x M are characterized with a fracture toughness of 5 MPa × m^0.5, which is over 50% higher than in the case of the reference sample and over 15% higher than for the composite with 2.5 wt.% addition of Ti₃C₂T_x, which showed the highest fracture toughness in this series.     

Characterizing the Chemical Structure of Ti3C2Tx MXene by Angle-Resolved XPS Combined with Argon Ion Etching

Angle-resolved XPS combined with argon ion etching was used to characterize the surface functional groups and the chemical structure of Ti₃C₂T_x MXene. Survey scanning obtained on the sample surface showed that the sample mainly contains C, O, Ti and F elements, and a little Al element. Analyzing the angle-resolved narrow scanning of these elements indicated that a layer of C and O atoms was adsorbed on the top surface of the sample, and there were many O or F related Ti bonds except Ti–C bond. XPS results obtained after argon ion etching indicated staggered distribution between C–Ti–C bond and O–Ti–C, F–Ti bond. It is confirmed that Ti atoms and C atoms were at the center layer of Ti₃C₂T_x MXene, while O atoms and F atoms were located at both the upper and lower surface of Ti₃C₂ layer acting as surface functional groups. The surface functional groups on the Ti₃C₂ layer were determined to include O²⁻, OH⁻, F⁻ and O⁻–F⁻, among which F atoms could also desorb from Ti₃C₂T_x MXene easily. The schematic atomic structure of Ti₃C₂T_x MXene was derived from the analysis of XPS results, being consistent with theoretical chemical structure and other experimental reports. The results showed that angle-resolved XPS combing with argon ion etching is a good way to analysis 2D thin layer materials.     

Design an Epoxy Coating with TiO2/GO/PANI Nanocomposites for Enhancing Corrosion Resistance of Q235 Carbon Steel

In this work, a ternary TiO₂/Graphene oxide/Polyaniline (TiO₂/GO/PANI) nanocomposite was synthesized by in situ oxidation and use as a filler on epoxy resin (TiO₂/GO/PANI/EP), a bifunctional in situ protective coating has been developed and reinforced the Q235 carbon steel protection against corrosion. The structure and optical properties of the obtained composites are characterized by XRD, FTIR, and UV–vis. Compared to bare TiO₂ and bare Q235, the TiO₂/GO/PANI/EP coating exhibited prominent photoelectrochemical properties, such as the photocurrent density increased 0.06 A/cm² and the corrosion potential shifted from −651 mV to −851 mV, respectively. The results show that the TiO₂/GO/PANI nanocomposite has an extended light absorption range and the effective separation of electron-hole pairs improves the photoelectrochemical performance, and also provides cathodic protection to Q235 steel under dark conditions. The TiO₂/GO/PANI/EP coating can isolate the Q235 steel from the external corrosive environment, and may generally be regarded a useful protective barrier coating to metallic materials. When the TiO₂/GO/PANI composite is dispersed in the EP, the compactness of the coating is improved and the protective barrier effect is enhanced.     

A Novel Exploration of a Combination of Gambogic Acid with TiO2 Nanofibers: The Photodynamic Effect for HepG2 Cell Proliferation

As a good photosensitizer, TiO₂ nanomaterials show potential biomedical applications, such as drug carriers or enhancers in photodynamic therapy. In this contribution, novel nanocomposites through the blending of TiO₂ nanofibers with the active compound, gambogic acid (GA), were explored, and the results showed that GA could inhibit cancer cell proliferation in a time-dependent and dose-dependent manner, inducing apoptosis and cell cycle arrest at the G0/G1 phase in HepG2 cells. It is evident that after the GA-TiO₂ nanocomposites were cultured with the cancer cells, the cooperation effect could effectively enhance the cytotoxicity of GA for HepG2 cells. Meanwhile, if activated by UV irradiation, under the presence of GA-TiO₂ nanocomposites, this would lead to significant apoptosis and necrosis for HepG2 cells with a photodynamic therapy (PDT) effect. Associated with the controlled drug-release from these nanocomposites, TiO₂ nanofibers could readily cut down the drug consumption in HepG2 cells and reduce the side-effect for the normal cells and tissue, which may be further utilized in the therapeutic alliance for cancer therapy.