Pure Polyimide Film Research Articles

Thermal, Mechanical and Dielectric Properties of Polyimide Composite Films by In-Situ Reduction of Fluorinated Graphene.

Materials with outstanding mechanical properties and excellent dielectric properties are increasingly favored in the microelectronics industry. The application of polyimide (PI) in the field of microelectronics is limited because of the fact that PI with excellent mechanical properties does not have special features in the dielectric properties. In this work, PI composite films with high dielectric properties and excellent mechanical properties are fabricated by in-situ reduction of fluorinated graphene (FG) in polyamide acid (PAA) composites. The dielectric permittivity of pure PI is 3.47 and the maximum energy storage density is 0.664 J/cm3 at 100 Hz, while the dielectric permittivity of the PI composite films reaches 235.74 under the same conditions, a 68-times increase compared to the pure PI, and the maximum energy storage density is 5.651, a 9-times increase compared to the pure PI films. This method not only solves the problem of the aggregation of the filler particles in the PI matrix and maintains the intrinsic excellent mechanical properties of the PI, but also significantly improves the dielectric properties of the PI.

Influence of metallization on the mechanical properties of polyimide films

The need to obtain and study the properties of metallized polymeric materials is associated with their wide application in space exploration, electronics, and the production of consumer goods. The main directions in the search for new materials are aimed at obtaining composite films with different distributions of the metal phase over the thickness while maintaining the mechanical characteristics. The most promising metallized polymer materials are polyimides with high thermal stability, good dielectric properties, and low expansion coefficient. Therefore, the study of viscosity, strength, and other mechanical characteristics of metallized polymeric materials, the determination of the effect of the coating structure on their mechanical behavior, and the development of methods for predicting their behavior are currently relevant and important tasks. Methods for improving the mechanical properties of polyimide films by silver plating have been studied. The thickness of the metal layer of the polyimide base, which is part of the structure, ranged from 1 to 5 μm. Surface coatings were 80–97% of comparable silver mirrors in the visible and infrared regions. The deformation of the samples was carried out at room temperature on an Instron 5982 universal testing machine in the uniaxial tension mode. As a result of the metallization of the films, a significant increase in mechanical characteristics was observed compared to a pure polyimide film. An increase in ultimate strength by ∆σ = 105 MPa and plasticity by ∆ε = 75% was obtained, which is associated with a change in the structure of metallized films and the conditions of their chemical treatment.

Preparation and properties of polyimide dielectric nanocomposites containing polyvinylpyrrolidone chemically functionalized barium titanate by in‐situ synthesis compounding

AbstractThis work employed polymer active agent polyvinylpyrrolidone (PVP) treated barium titanate (BT) nanoparticles (PVP@BT) as functional nanofillers to fill polyimide (PI) matrix to fabricate PI nanocomposite films. The microstructure, dielectric properties, and heat resistance of PI, PI/BT, and PI/PVP@BT dielectric nanocomposite films were investigated. Fourier transform infrared spectrometer (FTIR) indicated that PVP has been successfully coated on the surface of BT nanoparticles. Due to the enhanced aggregation of monomers on the PVP@BT nanoparticles, higher molecular weight and viscosity of PI/PVP@BT nanocomposite films were achieved. Compared with PI/BT nanocomposite films, the dispersion of PVP@BT nanoparticles in PI/PVP@BT nanocomposite films was better, as verified by field emission scanning electron microscope and high‐resolution transmission electron microscopy. Filling a small amount of PVP@BT nanoparticles into the PI matrix improved the dielectric properties of the resultant nanocomposite films. The dielectric constant of the nanocomposite films with 10 wt% filler loading was up to 7.1 at 1000 Hz, which was 2.5 times higher than that of pure PI (2.9). PI nanocomposite film dielectric loss was generally lower than 0.015. Thermogravimetric analysis (TGA) tests verified that both pure PI and PI nanocomposite films showed excellent thermal stability. This work can be expected to provide a new strategy for designing and manufacturing PI dielectric nanocomposite films for energy storage applications.

Hierarchical Amine-Functionalized ZIF-8 Mixed-Matrix Membranes with an Engineered Interface and Transport Pathway for Efficient Gas Separation

Herein, we report a facile approach to engineer a metal–organic framework (MOF) structure and polymer–MOF interface in a mixed-matrix membrane (MMM) to achieve high gas separation performance and plasticization resistance. Hierarchical ZIF-8-NH2 nanoparticles with a relatively small concentration of amine functionality (∼5 mol %) were prepared. The hierarchical MOF structure provides fast molecular transport pathways because of the MOF–MOF percolated network and high MOF packing density. Moreover, the interfacial interaction between the 6FDA-DAM:DABA(3:2) polyimide and the amine-functionalized MOF enhances the chemical stability and polymer chain rigidity. The hierarchical ZIF-8-NH2 MMMs exhibit a significantly improved gas permeability because of the accelerated molecular diffusion through the direction-oriented MOF pathway. For example, the ZIF-8-NH2 30 wt % MMM showed ∼6- and ∼4-fold enhanced H2 (761.7 Barrer) and CO2 (552.4 Barrer) permeabilities when compared to those of a pure polyimide film, with an H2/CH4 selectivity of 35.7 and CO2/CH4 selectivity of 25.9. Additionally, the MMM exhibits an improved plasticization resistance due to the connected MOF structure and MOF–polymer interaction. This strategy provides remarkable insight into the rational design of the polymer and MOF constituents in the MMM system.

Laser Shock Fabrication of Nitrogen Doped Inverse Spinel Fe3O4/Carbon Nanosheet Film Electrodes towards Hydrogen Evolution Reactions in Alkaline Media

The reliable and cost-effective production of high-performance film electrodes for hydrogen evolution reactions remains a challenge for the laser surface modification community. In this study, prior to a thermal imidization reaction, a small number of Fe3O4 nanoparticles were vortexed into a poly(amic acid) (PAA) prepolymer, and the achieved flat composite film was then ablated by a 1064 nm fiber laser. After laser irradiation, the hierarchical architectures of carbon nanosheets decorated with Fe3O4 nanoparticles were generated. Although pure polyimide (PI) film and laser carbonized PI film, as well as bare Fe3O4, showcase poor intrinsic catalytic activity toward alkaline hydrogen evolution reactions, our laser-derived Fe3O4/carbon nanosheet hybrid film demonstrated enhanced electrocatalytic activity and stability in 1 M KOH electrolyte; the overpotential(η10) reached 247 mV when the current density was 10 mA cm−2 with a slight current decay in the chronoamperometric examination of 12 h. Finally, we proposed that the substitution of N to O in Fe−O sites of trans spinel structured magnetite would be able to modulate the free energy of hydrogen adsorption (ΔGH*) and accelerate water dissociation.

Flexible and quasi-isotropically thermoconductive polyimide films by guided assembly of boron nitride nanoplate/boron nitride flakes for microelectronic application

• A hierarchical “brick and plank” structure is fabricated by dopamine modified h -BN nanomaterials. • This special structure can be used to improve the performance of polyimide. • The modified PI films have quasi-isotropic thermal conductivity and high thermal stability. • The modified PI films have good flexibility and excellent electrical insulation. • The modified PI films show faster shape memory response time reducing 50 %. Currently, the application of polyimide (PI) based materials often demands mutual additional properties, such as high thermal conductivity, good flexibility, high thermal stability and low dielectric constant and loss, etc. . Herein, a well-aligned hierarchical “brick and plank” architecture by rational assembly of dopamine modified hexagonal boron nitride flakes and nanoparticles (PDA-BNF@BNNPs) which can effectively improve the thermal conductivity, thermal stability, electrical conductivity, dielectric properties and shape memory performance of pure PI. The alternating stacking of vertically arranged h -BNNPs and horizontally laid h -BNFs yield a quasi-isotropic thermal conductivity of PI films with a high through-plane thermal conductivity of 6.43 W/(mK) and an in-plane thermal conductivity of 11.85 W/(mK) because of the simultaneously vertical and horizontal phonon scattering enabled by the vertically arranged h -BNNPs and horizontally laid h -BNFs. Besides, this special structure also endues PI films high thermal stability of over 560 °C, prominent electrical resistance of over 1.40 × 10 -13 Ω•cm, and low dielectric loss of less than 0.02 in the high frequency. Moreover, the PDA-BNF@BNNP/PI films exhibit excellent flexibility and shape memory performance with faster recovery response time reduced over 50 % comparing with that of pure PI film. These outstanding properties combining with the facile and scalable fabrication process make PDA-BNF@BNNP/PI films are very promising in diverse electronic device applications, especially in flexible electronic devices or circuits requiring additionally high thermal conductivity and low dielectric loss.

Ultrahigh thermal and electric conductive graphite films prepared by g-C3N4 catalyzed graphitization of polyimide films

• High-quality graphite film with high thermal and electric conductivity was obtained. • Using g-C 3 N 4 as catalyst can reduce the graphitization temperature and save energy. • Using g-C 3 N 4 as catalyst can reduce the graphitization temperature. • The new processes of the graphitization can save 20.5% energy. High-efficiency heat-dissipation materials are in urgent need in microelectronics industry in 5G era. However, large-scale, low-cost, and high-efficiency preparation technologies still have great challenges. Here, ultrahigh thermal and electric conductive graphite films prepared by graphite-phase carbon nitride (g-C 3 N 4 ) catalyzed graphitization of polyimide film (PI) were reported for the first time. The graphite film obtained from 0.25 wt% g-C 3 N 4 catalyzed polyimide graphitization (G0.25) has homogeneous and perfect graphene structure and state-of-the-art properties. The d -spacing of the graphite layers is about 0.335 nm, which is similar to the ideal layer thickness of graphene (0.334 nm). The thermal conductivity is 1781 W·m −1 ·K −1 and the conductivity is 1.63 × 10 6 S·m −1 , which is 1.49 and 2.18 times of graphite film from pure PI film, 1.94 and 2.34 times of graphite film from commercialized Kapton film (I-film), respectively. The thermal conductivity of G0.25 film is 4.52 times of Cu and 7.46 times of Al. More importantly, the addition of g-C 3 N 4 can reduce the graphitization temperature from 2800 to 2500 ℃, which can reduce the energy consumption by 20.5% in the whole polyimide graphitization process. The developed preparation technology has important guiding significance and very attractive industrial application value for the preparation of large-scale, low cost and high-quality heat dissipation materials.

Hyper cross‐linked polymers containing amino group functionalized polyimide mixed matrix membranes for gas separation

AbstractThe design and synthesis of porous materials with novel structures and functional groups to prepare mixed matrix membranes (MMMs) is an effective way to break through trade‐off effect of membrane technology. Here, hyper cross‐linked polymers containing amino groups (HCPs‐NH2) with philic‐CO2 frame were successfully prepared for the fabrication of polyimide (PI)/HCPs‐NH2 MMMs. The separation performance of pure gas is studied in order to explore NH2 groups facilitating CO2 diffusion and transmission and enhancing CO2 permeability. Consequently, the permeability of the PI/HCPs‐NH2 MMMs toward CO2 and O2 are 77.56 Barrer and 17.91 Barrer versus pure PI film toward CO2 and O2 (62.42 Barrer and 13.85 Barrer). The selectivity for CO2/CH4 and O2/N2 pairs is 24.44 and 4.01, and the selectivity of pure PI film toward CO2/CH4 and O2/N2 pairs is 20.76 and 3.29, respectively. The permeability and selectivity of PI/HCPs‐NH2 MMMs are higher than pure PI film breaking through the trade‐off effect. Moreover, the PI/HCPs‐NH2 MMMs show better separation performance on the CO2/CH4 pair than the O2/N2 pair, indicating HCPs‐NH2 with philic‐CO2 frame plays a very important role in promoting CO2 permeability. Thus, the PI/HCPs‐NH2 MMMs have potential applications in the field of natural gas purification.

Study on High Frequency Surface Discharge Characteristics of SiO2 Modified Polyimide Film.

Polyimide (PI) can be used as a cladding insulation for high frequency power transformers, and along-side discharge can lead to insulation failure, so material modification techniques are used. In this paper, different doped nano-SiO2 are introduced into polyimide for nanocomposite modification. The results of testing the life time of high-frequency electrical stress along-side discharge show that the 10% SiO2 doping has the longest life time. The results show that: for composites prone to corona, their flashover causes more damage, and both positive half-cycle and polarity reversal discharges are more violent; compared to pure PI, the positive half-cycle and overall discharge amplitude and number of modified films are smaller, but the negative half-cycle is larger; at creeping development stages, the number of discharges is smaller, and the discharge amplitude of both films fluctuates in the mid-term, with the modified films having fewer discharges and the PI films discharging more violently in the later stages. The increase in the intensity of the discharge was greater in the later stages, and the amplitude and number of discharges were much higher than those of the modified film, which led to a rapid breakdown of the pure polyimide film. Further research found that resistivity plays an important role in the structural properties of the material in the middle and late stages, light energy absorption in the modified film plays an important role, the distribution of traps also affects the discharge process, and in the late stages of the discharge, the heating of the material itself has a greater impact on the breakdown, so the pure polyimide film as a whole discharges more severely and has the shortest life.

Polyimide composite films reinforced by graphene quantum dots

Polyimide composite films have been widely used in some advanced field of microelectronic devices, precision instruments and national defense applications. Graphene quantum dots have great application potential in polymer doping modification because of their good mechanical strength, high specific surface area and excellent tunability of physical and chemical properties. In this paper, Graphene quantum dots are prepared by pyrolysis at different temperatures. The results show that different reaction temperatures have a great influence on the size and size distribution of graphene quantum dots. When the pyrolysis temperature is 200 °C, the size of graphene quantum dots is uniform at 3–5 nm. Graphene quantum dots-polyimide nanocomposite films prepared by in-situ polymerization show excellent mechanical properties. When the doping amount of graphene quantum dots is 0.5 wt%, the tensile strength and elastic modulus of the composite films can reach 130.24 MPa and 2.93 GPa respectively, which are 41.3% and 108% higher than that of pure polyimide films, respectively. Moreover, the thermal stability of polyimide composite films increases with the increase of the doping amount of graphene quantum dots. This shows that graphene quantum dots have good dispersion in polyimide matrix and can effectively improve the interface of composites. These results provide a successful preparation method to help guide to fabricate graphene quantum dots-polyimide composite films with high performance for the advanced applications.

High oriented graphite film with high thermal conductivity prepared by pure polyimide film formed with catalyst pyridine

Highly oriented graphitized films demonstrate outstanding thermal conductivity in recent telecommunication applications. In this work, polyimide films were prepared with catalyst pyridine. High orientated and high thermal conductive graphite films were successfully prepared by pure polyimide (PI) films without any other carbon source inducing growth. The result showed that pyridine could promote the imidization of PI. Suitable dosages of pyridine can improve the crystallinity, promote the orderly arrangement of molecular chains, and facilitate the growth of the crystal lattice after graphitization. After graphitization, graphitized PI films exhibited highly oriented layers. The graphitized film coming from a pyridine concentration of 3.5 wt% provided the best thermal conductivity (1092 W/(m.K)), which was 49 times more than those from the thermally imidized films. The average crystalline size of it was 62.16 nm and its degree of graphitization was 90%. Therefore, the graphite film prepared by polyimide formed with catalyst pyridine has the potential of thermal management and is a highly prospective candidate as heat dissipation substrates for miniaturization electronic devices.

Binary polymer blend of ArPTU/PI with advanced comprehensive dielectric properties and ultra‐high thermally stability

AbstractFlexible high‐temperature polymeric dielectrics with advanced dielectric properties are urgently demanded in various applications. In this work, series of polymer blend films were prepared from aromatic polythiourea (ArPTU) and polyimide (PI). The experimental results revealed that the blend films were properly engineered to achieve higher breakdown strength, greater dielectric constant, and larger energy density than pure PI film. For instance, the optimum property was obtained from the blend film with 10 wt% ArPTU, exhibiting prominent dielectric properties (K = 4.52, Eb = 443 MV/m), enhanced energy density (4.00 J/cm3) as well as excellent heat resistance (Tg = 419°C). In addition, stable dielectric properties at broad temperature range from −50 to 250°C were also acquired. It is deduced that the good compatibility from ArPTU and PI with similar polarity are responsible for the improved properties. The superior comprehensive properties which combine the advantages of ArPTU and PI suggest the potential applications of ArPTU/PI blend film in high‐temperature dielectric areas.

Study of the kinetics of gas evolution of a polymer composite under the influence of vacuum and VUV

The paper presents data on the effect of high vacuum and vacuum ultraviolet (VUV) on a polymer composite based on polyimide track membranes. Polyimide track membranes were filled with POSS structures. For comparison, we also used pure polyimide films without filler. Exposure in high vacuum and surface treatment of the developed VUV composite were carried out in the imitation chamber of near-Earth space, located in the Space Materials Science Laboratory of BSTU named after V.G. Shukhov (Russia, Belgorod). The high resistance of the composite to high vacuum and VUV has been established. The total weight loss of the composite by 24 hours was 0.26 wt. % (after holding in vacuum) and 0.28 wt. % (after VUV).

Charge Transport and Trapping of Surface Modified Stator Coil Insulation of Motors

This paper presents the surface modification and charge transportation mechanism of thin polyimide films. Here, we demonstrate that the surface modification of these films, by using the fluorine gas-phase, improves the charges mitigation and, thereafter, suppress the space charges. The experimental results indicate that the thermal step current for fluorine coated films reduce significantly in comparison to pure polyimide films. The thin layer of fluorine coating helps to release the surface charge, reduce the charge injection from the electrode, provide hindrance for charges to penetrate into the bulk of the films and the higher degree of charge disappearing helps to reduce the space charge growth.

Polyimide hollow glass microspheres composite films with low dielectric constant and excellent thermal performance

AbstractNowadays, polyimide (PI) with low dielectric constant is expected to be widely applied in microelectronics. For this reason, hollow glass microspheres (HGM) modified by silane coupling agent KH‐550 (K‐HGM), a series of HGM/PI and K‐HGM/PI composite films with excellent thermal performance, hydrophobic and low dielectric constant were fabricated by in situ polymerization. The effect of HGM/K‐HGM content on the properties of composite films was studied. The superior heat resistance of HGM can improve the thermal performance of composite films. Due to silane coupling agent KH‐550, K‐HGM exhibits a good interfacial compatibility with PI matrix and forms an interfacial adhesion region. With the HGM loading of 6%, comparing with pure PI films, the glass transition temperatures (Tg) of composite films were dramatically increased by 32.3°C. Especially, the low dielectric constant of 2.21 and dielectric loss of 0.0059 at 1 MHz were obtained for the PI/K‐HGM composite film with addition of 8 wt%. Thus, PI/K‐HGM composite films show more excellent performance. The current work provides a promising solution for fabrication of PI with low dielectric constant and superior thermal performance that may be applied in microelectronics industry.

Enhanced thermal conductivity of carbon nitride-doped graphene/polyimide composite film via a “deciduous-like” strategy

Driven by the rapid development of modern electronics in minimization, high integration and high-power density, tailored polymer films with high thermal conductivity and electrical insulation have made great progress. However, traditional approaches for enhancing thermal conductivity usually sacrifices processibility, electrical insulation and mechanical flexibility of the polymer films. Here, after settling doping reduced graphene oxide with carbon nitride (rGO@CN) in polyimide film (PI) by a facile deciduous-like strategy, we obtain polyimide film with both high thermal conductivity and satisfied electrical insulation at low filler loading. By taking the advantage of thermally conductive channels provided by continuous rGO@CN layer, PI/rGO@CN composite film at 10 wt% filler loading exhibits a maximum thermal conductivity of 6.08 Wm−1K−1 which is about 30-fold compared with that of pure PI film (0.2 Wm−1K−1). Besides, the PI/rGO@CN composite film also maintains excellent electrical insulation, mechanical flexibility and thermal stability. Furthermore, the thermal conductivity of rGO@CN has been further explored by non-equilibrium molecular dynamics simulation. This work provides new strategy for the industrial production of PI film with high thermal conductivity and electrical insulation.

Effects of Material Preparation in Polyimide/SiO2 Nanocomposites for Low-Temperature Dielectric Applications

Introducing nanomaterial fillers into a host polymer can significantly change its properties and affect its behaviors. The resulting nanocomposites have the potential to possess new, often enhanced characteristics, making them uniquely qualified for a broader spectrum of new applications. This research investigates the effects of material preparation on nanocomposites using polyimide (PI) as the host polymer and silicon dioxide (SiO2) nanoparticles as the filler. The fabrication and characterization of the PI/SiO2 nanocomposites were explored based on samples produced from two different approaches—a direct mixing process using as-purchased SiO2 nanoparticles and a sol-gel process that relied on chemical reactions to produce SiO2 inside a solvent. The prepared samples and the distribution of the SiO2 nanoparticles in the nanocomposites were characterized with profilometry and scanning electron microscopy (SEM). The characterization showed that the directly mixed samples contained visible nanoparticle agglomerates while the sol-gel films had the nanoparticles uniformly distributed inside the host polymer. The DC dielectric breakdown testing revealed that the sol-gel films outperformed the directly mixed samples at both room (300 K) and cryogenic (164 K) temperatures. When the temperature is cooled down to 92 K, the sol-gel samples demonstrated higher dielectric strengths than pure PI films. Our investigation shows that high-quality PI/SiO2 nanocomposites, especially when prepared through the sol-gel process, are promising candidates as dielectrics that can be used in a variety of cryogenic applications.

Dielectric, thermally conductive, and heat-resistant polyimide composite film filled with silver nanoparticle-modified hexagonal boron nitride

In this study, silver–polydopamine–hexagonal boron nitride (h-BN@Ag) particles were prepared using mussel chemistry and reducibility of catechol. The modified method was simple and eco-friendly. In addition, we prepared h-BN@Ag/polyimide (PI) composite films via in situ polymerization, the scraper method, and thermal imidization. Owing to the good dispersion of the h-BN@Ag filler particles in the PI matrix and the bridging role of the Ag nanoparticles, the thermal conductivities of the h-BN@Ag/PI composite films were higher than that of the pure PI film. The thermal conductivity of the h-BN@Ag/PI film with the filler content of 10 wt% was 0.382 W (m·K)−1, which was 108% higher than that of pure PI films (0.184 W (m·K) −1). Furthermore, the composite films presented extremely low dielectric permittivity and loss tangent. Moreover, the heat resistance index of the composite films (304.6°C) was higher than that of pure PI (294.3°C). Thus, h-BN@Ag/PI composite films could be promising electronic packaging materials.

Enhanced dielectric properties in polyimide nanocomposites containing barium titanate@ polydopamine core-shell nanoparticles

In this work, we prepared the polyimide (PI) nanocomposite films containing barium titanate @polydopamine (BT@PDA) nanoparticles within a core-shell structure by solution casting method. The dielectric constant of these nanocomposite films is significantly improved compared to pure PI film, and increases with the increase of BT nanoparticles. And, the breakdown strength of these nanocomposite films is better than that of untreated BT/PI films at the fixed BT content. The PI composite film containing 1 vol% of BT@PDA nanoparticles exhibits the highest energy storage density of 1.94 J/cm3 under an electric field of 315 kV/mm, which is 42% over the pristine PI (1.37 J/cm3 at 295 kV/mm) and about 162% greater than biaxially-oriented polypropylene (BOPP) (≈1.2 J/cm3 at 640 kV/mm). The presence of PDA shell effectively improves the dispersion uniformity and interfacial compatibility of BT nanoparticles in the PI matrix, giving rise to lower local electric field distortion in the composites. Besides, the BT@PDA/PI nanocomposite films have excellent dielectric thermal stability in the temperature range from 25 to 200 °C and thermal stability up to 500 °C. The BT@PDA/PI composites fabricated in this work have a great potential to be used in the high-temperature film capacitors.

Self-suspended carbon nanotube/polyimide composite film with improved photothermal properties

Self-suspended polyimide (PI) composite films were fabricated. Their diameter and thickness were 2.5 in. and 260 nm, respectively. A high ratio of diameter to thickness of 2.4 × 105 was obtained. The multiwalled carbon nanotubes (MWCNTs) were filled into PI to improve the optical absorption and the photothermal response. By using the N-methyl pyrrolidone solvent for both MWCNTs and poly(amic acid), a homogeneous dispersion of MWCNTs with up to 15% content was obtained. Under the thermal treatment of 300 °C, the composite films were successfully synthesized, which was proved by the measurements of Fourier transform infrared spectrum and x-ray diffraction. Compared with the pure PI film, the optical absorption of the composite films at 532 nm wavelength increased from 10% to 28%. The steady and transient photothermal properties of the composite films were investigated. In the steady state, a temperature rise of 145 °C was obtained under 0.7 W/cm2 illuminating laser power density. The temperature increased by 29 times compared with that of the pure PI film. The corresponding photothermal conversion efficiency improved to 70.8%. In the transient state, the photothermal response time was 7.5 ms, which was only half that of the pure PI film. The excellent photothermal properties of these self-suspended MWCNT/PI composite films highlight their potential applications in micro- and nanoscale devices for photo detection and thermal imaging.