Synthesis and microwave absorption properties of sandwich-type CNTs/Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>/RGO composite with Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> as a bridge

A novel sandwich-type CNTs/Fe₃O₄/RGO composite with Fe₃O₄ as a bridge was successfully prepared through a simple solvent-thermal and ultrasonic method. The structure and morphology of the composite have been characterized by Fourier-transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy. This new structure can effectively prevent the agglomeration of GO and the combination of CNTs/Fe₃O₄ and RGO shows a strong reflection loss (R_L) (?50 dB) at 8.7 GHz with absorber thickness of 2.5 mm. Moreover, compared with CNTs/Fe₃O₄/GO composite, it is found that the thermal treating process is beneficial to enhance the microwave absorption properties, which may be attributed to high conductivity of RGO. On this basis, the microwave absorbing mechanism is systematically discussed. All the data show that the CNTs/Fe₃O₄/RGO composite exhibits excellent microwave absorption properties with light density and is expected to have potential applications in microwave absorption.     

Facile synthesis and excellent electromagnetic wave absorption properties of flower-like porous RGO/PANI/Cu<Subscript>2</Subscript>O nanocomposites

Novel porous ternary nanocomposite systems containing reduced graphene oxide (RGO)/polyaniline (PANI)/cuprous oxide (Cu₂O) were prepared via one-step in situ redox method. The RGO/PANI/Cu₂O nanocomposites present a flower-like structure with an average size of 2.0 μm in diameter. The morphologies and properties of the products can be controlled by adjusting the molar ratios of aniline to Cu²⁺. When the molar ratio of aniline to Cu²⁺ is 1:1, the product exhibits excellent microwave absorption property in the frequency range of 2–18 GHz. It can be seen that the maximum reflection loss (RL) of the ternary composite is up to ?52.8 dB at 2.7 GHz with a thickness of only 2 mm, and the absorption bandwidth corresponding to ?10 dB (90% of EM wave absorption) is 13.2 GHz. The microwave absorption property of ternary RGO/PANI/Cu₂O composite is significantly improved due to its special flower-like porous structure, dielectric loss property and well impedance matching characteristics, which is 8.12 times than that of pure RGO and 5.28 times than that of pure PANI. Therefore, our study paves a new way to prepare the promising lightweight and high-performance composite materials combined with the characteristics of three components for electromagnetic absorption.     

Synthesis and microwave absorption property of ternary composites: polyaniline/CoFe<Subscript>2</Subscript>O<Subscript>4</Subscript>/Ba<Subscript>3</Subscript>Co<Subscript>2</Subscript>Fe<Subscript>24</Subscript>O<Subscript>41</Subscript>

Polyaniline (PANI)/CoFe₂O₄/Ba₃Co₂Fe₂₄O₄₁ composite was prepared by an in-situ polymerization method. The phase structure, morphology and magnetic properties of the as-prepared PANI/CoFe₂O₄/Ba₃Co₂Fe₂₄O₄₁ composite were characterized by XRD, FT-IR, SEM, TEM, and VSM, respectively. The microwave absorption properties of the composite were investigated by using a vector network analyzer in the 2–18 GHz frequency range. The results show that the maximum reflection loss value of the PANI/CoFe₂O₄/Ba₃Co₂Fe₂₄O₄₁ composite reaches ?30.5 dB at 10.5 GHz with a thickness of 3 mm and the bandwidth of reflection loss below ?10 dB reaches up to 1.2 GHz. The excellent microwave absorption properties of the as-prepared PANI/CoFe₂O₄/Ba₃Co₂Fe₂₄O₄₁ composite due to the enhanced impedance match between dielectric loss and magnetic loss.     

Fabrication and microwave absorption performances of hollow-structure Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>/PANI microspheres

The hollow polyaniline (PANI) microspheres were prepared by controlling the mass ratio of the aniline to polystyrene (PS) via a template method, and Fe₃O₄/PANI composite microspheres have been fabricated by blending the hollow PANI microspheres with Fe₃O₄ magnetic particles. The effects of the mass ratio of aniline/PS on the microwave absorption performances of Fe₃O₄/PANI microspheres were investigated. It was found that the value of minimum reflection loss (RL_min) of the microspheres were respectively ?14.06, ?22.34 and ?24.3 dB, corresponding to the mass ratio of aniline/PS of 1:1.5, 1:3, and 1:6. In addition, when the mass ratio of aniline/PS was 1:6, with the thickness of 1.5 and 2.0 mm, the bandwidth below ?10dB were respectively 2.48 GHz (15.52–18 GHz) and 4.64 GHz (11.04–15.68 GHz), indicating that the Fe₃O₄/PANI microspheres could be a potential electromagnetic wave absorbing material in X (8–12 GHz) and Ku (12–18 GHz) bands.     

Preparation of TiO<Subscript>2</Subscript>/Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>/CF composites for enhanced microwave absorbing performance

To meet the demand of electromagnetic absorption, cheap and easily available microwave absorbents are urgently required. As an important functional material, carbon fibers (CFs) have been widely reported, however, too high conductivity easily leads to the impedance mismatch, which is not favorable to the microwave absorbing performance (MAP). To address this challenge, in this study, novel TiO₂/Fe₃O₄/CF composites with tunable magnetic were synthesized by hydrothermal method and characterized by SEM, XRD, XPS and VSM. As absorbents, the minimum reflection loss (R_L) value is ??41.52 dB at a thickness of 2.1 mm, and the corresponding bandwidth with effective attenuation (R_L?<???10 dB) is up to 5.65 GHz (4.54–10.19 GHz). More importantly, the plausible mechanisms for the enhanced MAP are explored.     

Enhanced electromagnetic wave absorption properties of polyaniline-coated Fe3O4/reduced graphene oxide nanocomposites

Fe₃O₄-reduced graphene oxide-polyaniline (Fe₃O₄–RGO–PANI) ternary electromagnetic wave absorbing materials were prepared by in situ polymerization of aniline monomer on the surface of Fe₃O₄–RGO nanocomposites. The morphology, structure and other physical properties of the nanocomposites were characterized by X-ray diffraction, transmission electron microscopy, vibration sample magnetism, etc. The electromagnetic wave absorbing properties of composite materials were measured by using a vector network analyzer. The PANI–Fe₃O₄–RGO nanocomposites demonstrated that the maximum reflection loss was ?36.5 dB at 7.4 GHz with a thickness of 4.5 mm and the absorption bandwidth with the reflection loss below ?10 dB was up to 12.0 GHz with a thickness in the range of 2.5–5.0 mm, suggesting that the microwave absorption properties and the absorption bandwidth were greatly enhanced by coating with polyaniline (PANI). The strong absorption characteristics of PANI–Fe₃O₄–RGO ternary composites indicated their potential application as the electromagnetic wave absorbing material.     

Mn<Subscript>3</Subscript>O<Subscript>4</Subscript> nanoparticles embedded in 3D reduced graphene oxide network as anode for high-performance lithium ion batteries

Mn₃O₄ nanoparticles were in-situ synthesized in the 3D framework of reduced graphene oxide (RGO) by a facile one-step hydrothermal method. In the reduced graphene-Mn₃O₄ (RGM) composite, the RGO network not only serves as a mechanical support to construct a self-supported and binder-free electrode, but also offers 3D continuous conductive network for effective electron transfer. The Mn₃O₄ nanoparticles anchored uniformly across the RGO framework, which provided high capacity and prevented the restacking of the RGO thin sheets. Based on the unique composite structures, strong synergistic effect was achieved between Mn₃O₄ and RGO, resulting in superior specific capacity, enhanced rate capability, stable cycling performance and nearly 100% Coulombic efficiency in the RGM2 composites. With an optimal Mn₃O₄ composition of 44% by weight (similarly hereinafter), the composite exhibits high specific capacities of 696–795 mAh g¹ based on the overall weight of the electrode in 60 cycles at 200 mA g^?1, with a large coulombic efficiency of around 98%. Even at a high current density of 10,000 mA g^?1, the composite can still deliver a capacity of 383 mAh g^?1, demonstrating its excellent rate performance. The outstanding performances of the composites are attributed to the synergistic effect of both components and the hierarchical structure of the composite.     

Hierarchical structures based on Li<Subscript>0.35</Subscript>Zn<Subscript>0.3</Subscript>Fe<Subscript>2.35</Subscript>O<Subscript>4</Subscript>/polyaniline nanocomposites: synthesis and excellent microwave absorption properties

For the first time, the hierarchical structures of Li_0.35Zn_0.3Fe_2.35O₄(LZFO)/polyaniline nanocomposites were successfully synthesized by interfacial polymerization. Firstly, the LZFO particles were prepared by the sol–gel method, and subsequently the PANI nanorods, composed of nanoneedle-like PANI, were grafted on the surface of the LZFO. A novel microtopography, urchin-like, of LZFO/PANI was prepared by a simple, efficient and controllable two-step method. The crystal structure, chemical bonding states and morphology of samples were characterized by means of Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Scanning and Transmission electron microscopy (SEM/TEM). The bandwidth of reflection loss exceeds 10 dB in the frequency was 5.56 GHz (3.36–8.48, 10.32–10.76 GHz), and the maximum reflection loss can reach ??49.4 dB at 4.96 GHz with the thickness of 5.1 mm. The enhanced microwave absorption properties of LZFO/PANI nanocomposites are mainly ascribed to the multi-level structure and the improved impedance matching, and make it a potential candidate for microwave absorption materials.     

Synthesis and excellent microwave absorption property of polyaniline nanorods coated Li<Subscript>0.435</Subscript>Zn<Subscript>0.195</Subscript>Fe<Subscript>2.37</Subscript>O<Subscript>4</Subscript> nanocomposites

In this work, Li_0.435Zn_0.195Fe_2.37O₄ (LZFO) was firstly prepared by the sol–gel process, and then core–shell polyaniline (PANI) nanorods/LZFO composites were successfully synthesized by interfacial polymerization. The structures and morphologies of samples were characterized by means of X-ray diffraction, Fourier transform infrared spectra, and scanning electron microscopy. The average size of the pure ferrites was about 0.75 μm and the size distribution was 0.3–1.0 μm. The results indicated that the composites with different morphologies and structures resulted in different electromagnetic properties. The electromagnetic absorption test demonstrated that the PANI nanorods/LZFO possessed the best absorption property. The value of the minimum reflection loss was ?51.1 dB at 9.86 GHz, and the absorption bandwidth exceeding ?10 dB was 2.3 GHz (from 3.7 to 6 GHz) and 2 GHz (from 15.7 to 17.7 GHz). The excellent electromagnetic wave absorption properties of the nanocomposites were attributed to the improved impedance matching and the enhanced interfacial effects.     

The microwave absorbing properties of CoFe<Subscript>2</Subscript> attached single walled carbon nanotube/BaFe<Subscript>12</Subscript>O<Subscript>19</Subscript> nanocomposites

The CoFe₂ attached single-walled carbon nanotubes (CoFe₂@SWCNTs) and BaFe₁₂O₁₉ ferrite nanocomposites with different CoFe₂@SWCNTs weight ratios (1, 3, 5, 7 wt%) were synthesized by a simple combination process. Then, the electromagnetic and microwave absorption properties were systematically investigated by a vector network analyzer in the frequency range of 2–18 GHz. High-quality CoFe₂@SWCNTs were prepared by a direct current arc discharge method in one-step. BaFe₁₂O₁₉ nanocrystals were synthesized by a nitrate citric acid sol–gel auto-ignition method. The CoFe₂@SWCNT/BaFe₁₂O₁₉ nanocomposites exhibited an efficient reflection loss (RL) and a wide absorption bandwidth. The minimum RL of ?54.13 dB was observed at 11.84 GHz for the nanocomposite (5 wt% CoFe₂@SWCNTs) with a thickness of 2.8 mm, 3.4 times greater than those without CoFe₂@SWCNTs, and a broad absorption bandwidth of 4.64 GHz (<?10 dB) was achieved. In addition, the nanocomposite (1 wt% CoFe₂@SWCNTs) shows a broader effective microwave absorption bandwidth of 7.12 GHz with a thickness of 1.9 mm. The experimental results reveal that the absorbing properties of the nanocomposites are greatly improved by controlling the CoFe₂@SWCNTs weight ratio and the matching thickness of the absorber. This CoFe₂@SWCNT/BaFe₁₂O₁₉ nanocomposite is anticipated to be applied in advanced microwave absorbers.     

Effect of Ti<Subscript>3</Subscript>SiC<Subscript>2</Subscript> addition on microwave absorption property of plasma sprayed Ti<Subscript>3</Subscript>SiC<Subscript>2</Subscript>/NASICON coatings

The work attempted to develop a kind of high temperature microwave absorption coating. The Ti₃SiC₂/NASICON composite coatings with different Ti₃SiC₂ concentrations were fabricated by atmospheric plasma spraying. The effect of Ti₃SiC₂ addition on phase, density, microstructure, dielectric property and microwave absorption property of as-sprayed coatings was investigated. Results show that the complex permittivity increases with increasing the content of Ti₃SiC₂ due to the enhanced space charge polarization, decreased porosity and increased conduction loss. When the content of Ti₃SiC₂ increases to 30 wt%, the coating exhibits the optimal microwave absorption property with a bandwidth (below ??5 dB) of 4.01 GHz and lowest reflection loss of ??12.4 dB at 9.63 GHz in 1.4 mm thickness. It indicates that the Ti₃SiC₂/NASICON composite coating can be a potential candidate for microwave absorption.     

Synthesis and characterization of magnetic and microwave absorbing properties in polycrystalline cobalt zinc ferrite (Co<Subscript>0.5</Subscript>Zn<Subscript>0.5</Subscript>Fe<Subscript>2</Subscript>O<Subscript>4</Subscript>) composite

In this research work, magnetic and microwave absorption loss and other response characteristics in cobalt zinc ferrite composite has been studied. Cobalt zinc ferrite with the composition of Co_0.5Zn_0.5Fe₂O₄ was prepared via high energy ball milling followed by sintering. Phase characteristics of the as-prepared sample by using XRD analysis shows evidently that a high crystalline ferrite has been formed with the assists of thermal energy by sintering at 1250 °C which subsequently changes the magnetic properties of the ferrite. A high magnetic permeability and losses was obtained from ferrite with zinc content. Zn substitution into cobalt ferrite has altered the cation distribution between A and B sites in spinel ferrite which contributed to higher magnetic properties. Specifically, Co_0.5Zn_0.5Fe₂O₄ provides electromagnetic wave absorption characteristics. It was found that cobalt zinc ferrite sample is highly potential for microwave absorber which showed the highest reflection loss (RL) value of ??24.5 dB at 8.6 GHz. This material can potentially minimize EMI interferences in the measured frequency range, and was therefore used as fillers in the prepared composite that is applied for microwave absorbing material.     

The synergetic electromagnetic properties and enhanced microwave absorption of BiFeO<Subscript>3</Subscript>/BaFe<Subscript>7</Subscript>(MnTi)<Subscript>2.5</Subscript>O<Subscript>19</Subscript> composite

The effective microwave absorption materials could contribute to alleviating the electromagnetic wave pollution. However, conventional microwave absorption materials usually suffer from insufficient absorption intensity and the narrow effective absorption bandwidth. Herein, BiFeO₃/BaFe₇(MnTi)_2.5O₁₉ composites are proposed to address these issues through offering synergetic electromagnetic properties and proper electromagnetic properties. BiFeO₃ combined with BaFe₇(MnTi)_2.5O₁₉ exhibits dielectric multiple relaxation behaviors, strong ferromagnetic resonance and electromagnetic matching, ensuring increased multi-band microwave absorption. Accordingly, the minimum reflection loss (RL) of the composite with volume ratio of 1.5:1 reaches ??48 dB, and the bandwidth less than ??10 dB covers multi-frequencies at C, X and Ku band. These results suggest that BiFeO₃/BaFe₇(MnTi)_2.5O₁₉ composite could be a promising microwave absorption material in imaging, healthcare, information safety and military fields.     

Microwave absorption characteristics of CH<Subscript>3</Subscript>NH<Subscript>3</Subscript>PbI<Subscript>3</Subscript> perovskite/carbon nanotube composites

The CH₃NH₃PbI₃ (MAPbI₃) and CH₃NH₃PbI₃/carbon nanotube (MC) composite have been successfully synthesized by a facile in situ solution method, which are investigated as the microwave absorption materials. For the MAPbI₃ particles, the minimum reflection loss is only ?4.9 dB around 16.4 GHz due to the poor relative complex permittivity. Then, the relative complex permittivity of MC composites could be adjusted by changing the mass fraction of CNTs in composite, which is a vital role for the dielectric loss. The reflection loss of MC-5 composite (MAPbI₃/CNT, 5:1 wt%) can be improved to ?35.7 dB with thickness of 1.3 mm at 13.1 GHz. When the thickness is <3.0 mm, the microwave absorption bandwidth of MC-5 is 11.8 GHz (5.0–16.8 GHz) under the reflection loss lower than ?20 dB. The quarter-wavelength (λ/4) matching model is used to discuss the microwave absorption mechanism of MC composites. These results indicate that MC-5 composite could be used as the microwave absorption materials with strong reflection loss, lightweight and broad bandwidth.     

Electromagnetic wave absorption in reduced graphene oxide functionalized with Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>/Fe nanorings

We report the preparation of nanocomposites of reduced graphene oxide with embedded Fe₃O₄/Fe nanorings (FeNR@rGO) by chemical hydrothermal growth. We illustrate the use of these nanocomposites as novel electromagnetic wave absorbing materials. The electromagnetic wave absorption properties of the nanocomposites with different compositions were investigated. The preparation procedure and nanocomposite composition were optimized to achieve the best electromagnetic wave absorption properties. Nanocomposites with a GO:α-Fe₂O₃ mass ratio of 1:1 prepared by annealing in H₂/Ar for 3 h exhibited the best properties. This nanocomposite sample (thickness = 4.0 mm) showed a minimum reflectivity of–23.09 dB at 9.16 GHz. The band range was 7.4–11.3 GHz when the reflectivity was less than–10 dB and the spectrum width was up to 3.9 GHz. These figures of merit are typically of the same order of magnitude when compared to the values shown by traditional ferric oxide materials. However, FeNR@rGO can be readily applied as a microwave absorbing material because the production method we propose is highly compatible with mass production standards.

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Electromagnetic wave absorption properties in the centimetre-band of Ti<Subscript>3</Subscript>C<Subscript>2</Subscript>T<Subscript>x</Subscript> MXenes with diverse etching time

In this work, Ti₃C₂T_x MXenes were fabricated by using HF solution for diverse etching time and then investigated as electromagnetic (EM) wave absorbing materials in the centimetre-band (2–18 GHz). Besides, the impact of etching time on the structure, morphology, surface termination and dielectric properties was explored. With growing etching time, the crystal structure and surface morphology of Ti₃C₂T_x MXenes were gradually destroyed and more C was exposed. Among the etching samples, Ti₃C₂T_x-24 exhibited optimal RL_min of ??42.5 dB and broad tunable absorption bandwidth of 13.8 GHz. The extraordinary absorption could be attributed to multiple reflections and scatterings and interfacial polarizations. More importantly, comprehensive comparisons were made among two-dimensional Ti₃C₂T_x MXenes, typical two-dimensional carbon-related and MoS₂ materials. The thorough explorations supplement and improve the study of dielectric properties and EM wave absorption performance of Ti₃C₂T_x MXenes in centimetre-band, thus broadband Ti₃C₂T_x based hybrids absorbers can be constructed reasonably and effectively.     

Thermodynamic properties of SrAl<Subscript>12</Subscript>O<Subscript>19</Subscript> and SrAl<Subscript>4</Subscript>O<Subscript>7</Subscript>

Strontium aluminates are important compounds with interesting properties such as long-duration phosphorescence and elastico-deformation luminescence. They have potential application in flexible light emitting panels. Since there are serious discrepancies in available thermodynamic data for these compounds, a redetermination of their Gibbs energies of formation was undertaken using solid-state electrochemical cells incorporating single-crystal SrF₂ as the electrolyte in the temperature range from 1000 to 1300 K. However, the measurements were restricted to SrAl₁₂O₁₉ and SrAl₄O₇ because of the formation of strontium oxyfluoride phase between SrAl₂O₄ and SrF₂. For the reactions, SrO + 6 Al₂O₃ → SrAl₁₂O₁₉, ΔG ^o/J mol^?1 (± 280) = ?83386 ? 25.744 (T/K), and SrO + 2Al₂O₃ → SrAl₄O₇, ΔG ^o/J mol^?1 (± 240) = ?80187 ? 25.376 (T/K). The high entropy of SrAl₄O₇ and SrAl₁₂O₁₉ can be partly related to their complex structures. The results of this study are consistent with calorimetric data on enthalpy of formation of other Sr-rich aluminates and indicate only marginal stability for SrAl₄O₇ relative to its neighbours, SrAl₁₂O₁₉ and SrAl₂O₄. The thermodynamic data explain the difficulty in direct synthesis of phase pure SrAl₄O₇ and the formation of SrAl₂O₄ as the initial ternary phase when reacting SrO and Al₂O₃ or crystallizing from amorphous state, irrespective of composition.     

Preparation of core-shell structured hollow glass microspheres/BaFe<Subscript>12</Subscript>O<Subscript>19</Subscript>/Ag composites with excellent microwave absorbing properties

Hollow glass microspheres/barium ferrite (HGM/BaFe₁₂O₁₉) was first prepared via co-precipitation reaction, which was then performed to fabricate the HGM/BaFe₁₂O₁₉/Ag composites by chemical plating method. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and vibrating sample magnetometry (VSM) were utilized to characterize the structures, morphologies and properties of the resultant composites. Results showed that a homogeneous and complete BaFe₁₂O₁₉ shell was coated on the surface of the HGM, and HGM/BaFe₁₂O₁₉ composites were also fully covered with Ag particles. The conductivity of the HGM/BaFe₁₂O₁₉/Ag composites was 1.24?×?10² S/cm, whereas the saturation magnetizations of the composites was reduced to 12.76 emu/g. The microwave absorption properties of the HGMs/BaFe₁₂O₁₉/Ag composites were significantly improved compared with those of HGMs/BaFe₁₂O₁₉ composites and BaFe₁₂O₁₉ particles. The reflection loss (R) showed that the bandwidth of reflection loss of HGM/BaFe₁₂O₁₉/Ag less than ?10 dB (90% absorption) was 2.1 GHz (from 10.3 to 12.4 GHz), herein, the minimum loss value was ?19.7 dB at 12.4 GHz.     

Investigation of Li<Subscript>2</Subscript>Zn<Subscript>3</Subscript>Ti<Subscript>4</Subscript>O<Subscript>12</Subscript>-based temperature stable dielectric ceramics for LTCC applications

A low temperature co-fired ceramic (LTCC) was fabricated at 910 °C /2 h from the powder mixture of Li₂Zn₃Ti₄O₁₂, TiO₂ and a B₂O₃–La₂O₃–MgO–TiO₂ glass (BLMT), and the influence of TiO₂ on microstructure and dielectric properties of the composite was investigated in the composition range (wt%) of 20BLMT–(80???x)Li₂Zn₃Ti₄O₁₂–xTiO₂ (x?=?0, 2.5, 5, 7.5, 9 and 10). The results showed that all samples consisted of Li₂Zn₃Ti₄O₁₂, TiO₂, LaBO₃ and LaMgB₅O₁₀ phase. And LaBO₃, LaMgB₅O₁₀ and a small amounts of TiO₂ were crystallized from BLMT glass during sintering process. As x increases, dielectric constant and temperature coefficient of resonance frequency of the composites demonstrated gradually increase, whereas the quality factor of the sample of x?=?0 wt% was about 41,500 GHz and the ones maintained stable at a high level of 49,000–51,000 GHz for other samples. The composite with x?=?9 wt% had an optimal microwave dielectric properties with the dielectric constant of 20.2, quality factor of 50,000 GHz and temperature coefficient of resonant frequency of ??0.33 ppm/°C.     

Enhancement of the optical and mechanical properties of chitosan using Fe<Subscript>2</Subscript>O<Subscript>3</Subscript> nanoparticles

In this work, the optical and mechanical properties of Fe₂O₃ nanoparticles (NPs)/chitosan nanocomposite films have been investigated. Nanocomposite films of different weight ratios of Fe₂O₃ NPs/chitosan (0, 1, 5, 10, 20 and 30 wt%) were fabricated using casting technique. The optical properties of colloidal Fe₂O₃ NPs and Fe₂O₃ NPs/chitosan nanocomposite films were recorded using UV–visible spectrophotometer. As the ratio of Fe₂O₃ NPs to chitosan increases from 0 to 30%, the energy band gap of Fe₂O₃ NPs/chitosan films decreases from 3.16 to 2.11 eV. This decrease is due to quantum confinement effect. The mechanical properties of the nanocomposite films as a function of sweeping temperature were measured using a dynamic mechanical analyzer. An enhancement in storage modulus, stiffness and glass transition temperature (T_g) has been observed as the ratio of Fe₂O₃ NPs/chitosan increases. T_g of Fe₂O₃ NPs/chitosan nanocomposite film shifts towards higher temperature side with respect to pure chitosan film from 152.1 to 166.3?°C as the ratio of Fe₂O₃ NPs/chitosan increases from 0 to 30 wt%. The increase in T_g is mainly attributed to the decrease in free volumes and vacancies in the nanocomposite films as the weight ratio of Fe₂O₃ NPs/chitosan increases.