Novel low‐dielectric‐constant fluorine‐functionalized polysulfone with outstanding comprehensive properties

In this work, a series of fluorine‐functionalized polysulfone (F‐PSU) copolymers with intrinsic low dielectric constants (low ε) are reported, which are derived from the polycondensation reaction of 4,4′‐dichlorophenyl sulfone with bisphenol A and bisphenol F (BPF) compounds. The resulting F‐PSU copolymers show high glass transition temperatures (T_g) varying from 187 to 201 °C and are thermally stable up to 500 °C under an N₂ atmosphere. The introduction of BPF units into the PSU copolymers imparts enhanced hydrophobic properties to the F‐PSU films with increased water contact angle values from 66.2° to 93.7°. Moreover, the dielectric constant and dielectric loss of the F‐PSU (sample V) film are as low as 2.2 and 0.003 at 1 kHz, respectively. Interestingly, the dielectric properties are relatively stable to near the glass transition temperature, which is because of the existence of BPF structures in the molecular backbone. Furthermore, the F‐PSU copolymers are soluble in common solvents and can be readily fabricated into flexible transparent films by the spin casting method. © 2020 Society of Chemical Industry     

Polyimide–polydimethylsiloxane copolymers for low‐dielectric‐constant and moisture‐resistance applications

Novel, randomly coupled, soluble, segmented polyimide–polydimethylsiloxane (PI–PDMS) copolymers were prepared from aminoalkyl‐terminated polydimethylsiloxane (At–PDMS), 4,4′‐oxydianiline diamine, pyromellitic dianhydride, and 4,4′‐diphenylmethane diisocyanate (MDI). When At–PDMS was introduced into the polyimide chain, the polyimide copolymers exhibited lower dielectric constants and better moisture resistance and mechanical properties. The reductions in the dielectric constant of the PI–PDMS copolymers could be attributed to the incorporation of polydimethylsiloxane (PDMS) into the polyimide chain and the nanopores in the film generated by carbon dioxide evolvement during the reaction. The lowest dielectric constant was 2.58 with 25 wt % PDMS and 5 wt % MDI. In addition, the water contact angles of the resultant copolymers increased from 51 to 109° when the contents of PDMS increased from 0 to 25 wt %. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Formation of nanoporous poly(methyl silsesquioxane) thin films using adamantane for low‐k application

Nanoporous poly(methyl silsesquioxane) PMSSQ thin films for low‐k application have been prepared using chemically attached adamantylphenols as pore generating materials (porogen). To obtain the mechanically stable porous structure, multifunctional 1,2‐bistrimethoxysilylethane (BTMSE) was employed in addition to methyltrimethoxysilane as a main matrix material. From the decomposition of porogen, confirmed by FTIR and TGA, the nanoporous thin films containing pores less than 5 nm, which are characterized using sorption analysis, were successfully achieved. The dielectric constant was significantly decreased to 1.9, while maintaining the stable mechanical properties with the elastic modulus of 3.7 GPa measured by a nanoindenter. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Novel polyimide/graphene oxide composite films with ultralow dielectric constants

Graphene is generally used for conductive material; it can also be used as a key nanofiller for the insulation material of inverter motors. In this study, a series of polyimide (PI) films were prepared successfully by a conventional two‐step polymerization method based on bis[3,5‐dimethyl‐4‐(4‐aminophenoxy)phenyl]methane as a diamine and 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride as a dihydride with different weight percentage graphene oxide (GO) nanosheets as nanofillers. The dielectric constant (ε) and dielectric loss (tan δ) of these films were measured. The results show good dielectric properties, especially an ultralow ε value of 1.41 at 1 MHz with 0.19% GO. This showed that the low ε value was caused by a high free volume led by the GO nanosheets and the C? F bond. The structure and micromorphology of the PIs were characterized by X‐ray diffraction and scanning electron microscopy. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41385.     

Organosoluble,low‐dielectric‐constant fluorinated polyimides based on 2,6‐bis(4‐amino‐2‐trifluoromethylphenoxy)naphthalene

A novel fluorinated bis(ether amine) monomer, 2,6‐bis(4‐amino‐2‐trifluoromethylphenoxy) naphthalene, was prepared through the nucleophilic aromatic substitution reaction of 2‐chloro‐5‐nitrobenzotrifluoride and 2,6‐dihydroxynaphthalene in the presence of potassium carbonate, followed by catalytic reduction with hydrazine and Pd/C in ethanol. A series of novel trifluoromethylated polyimides were synthesized from the diamine with various commercially available aromatic tetracarboxylic dianhydrides using a two‐stage process with thermal imidization of poly(amic acid) films. Most of the resulting polyimides were highly soluble in a variety of organic solvents and could afford transparent and tough films via solution casting. These polyimides exhibited moderately high glass transition temperatures (T_gs) of 249–311 °C, high thermal stability and good mechanical properties. Low moisture (0.19–0.85 %), low dielectric constants (2.49–3.59 at 10 kHz), and low color intensity were also observed. For a comparative study, a series of analogous polyimides based on 2,6‐bis(4‐aminophenoxy)naphthalene were also prepared and characterized. Copyright © 2005 Society of Chemical Industry     

Functionalized KIT‐6/Terpolyimide composites with ultra‐low dielectric constant

Polyimides with low dielectric constants are important raw materials for the fabrication of flexible printed circuit boards and other microelectronic applications. As creation of voids in polyimide matrix could decrease dielectric constant, in this study mesoporous KIT‐6, synthesized hydrothermally, was functionalized with 3‐aminopropyltriethoxysilane (APTS) and mixed with 4,4′‐oxydianiline (ODA) in the synthesis of terpoly(amic acid) using 3,3′,4,4′‐biphenyldianhydride (BPDA), 3,3′,4,4′‐oxydiphthalic dianhydride (ODPA) and 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA) and subsequently stage‐cured to obtain APTS‐KIT‐6/Terpolyimide composites (APTS‐KIT‐6/TPI). The asymmetric and symmetric vibrations of imide O?C? N? C?O groups of APTS‐KIT‐6/TPI composites showed their peaks at 1772 and 1713 cm^?1. The dielectric constant decreased with the increase in KIT‐6 loading from 2 to 4%, but increased at higher loadings, and at 4% loading it was 1.42. Its tensile strength (103 MPa), tensile modulus (2.5 GPa), and percentage elongation (8.2) and high thermal stability (>540°C) were also adequate for application in microelectronics such as flexible printed circuits. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40508.     

A novel positive‐type photosensitive polyimide based on soluble block copolyimide showing low dielectric constant with a low‐temperature curing process

A soluble block copolyimide (Bco‐PI) was prepared by direct one‐pot polycondensation of 2,2‐bis‐(3‐amino‐4‐hydroxyphenyl)hexafluoropropane, 2,2‐bis[4‐(4‐aminophenoxy)phenyl]hexafluoropropane, and cyclohexane‐tetracarboxylic dianhydride in the presence of γ‐valerolactone and a pyridine catalyst system using γ‐butyrolactone as the solvent. The thermal transmission temperature (T_g) of Bco‐PI was 282°C. By having the curing process occur at 250°C, which was below the T_g, colorless and transparent films could be obtained. The film showed excellent optical characteristics. Such properties could not be attained by the conventional high‐temperature thermal imidization process of poly(amic acid). The hydroxy groups in the polyimide backbone gave the Bco‐PI the potential to become alkaline. To the Bco‐PI was added 15 wt % ester of 2,3,4‐trihydroxybenzophenone with 1,2‐naphthoquinone‐(2) diazide‐5‐sulfonic acid (NT200) as the photoreactive compound. The system worked as a positive‐type photosensitive polyimide (PSPI). The sensitivity and contrast of the PSPI system were 220 mJ/cm² and 1.27, respectively, when exposed to UV light, followed by development with a 5% tetramethylammonium hydroxide (TMAH) aqueous solution at room temperature. After curing at 250°C for 1 h, the average refractive index of Bco‐PI with and without NT200 was 1.5543 and 1.5563, and the optically estimated dielectric constant of the polyimides was 2.66 and 2.67, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4240–4246, 2006     

Silicon‐containing heterocyclic polymers and thin films made therefrom

Thin films, in the range of tens of micrometers thickness, have been prepared by casting onto glass plates the chloroform or N‐methylpyrrolidone solutions of polyimides or poly(imide‐amide)s containing silicon and phenylquinoxaline units in the main chain. The polymers have been synthesized by solution polycondensation reaction of aromatic diamines having preformed phenylquinoxaline rings with bis(3,4‐dicarboxyphenyl)dimethylsilane dianhydride or with a diacid chloride resulting from the reaction of this dianhydride with p‐aminobenzoic acid. The polymers were easily soluble in polar aprotic solvents and showed high thermal stability. The free‐standing films exhibited good mechanical properties with tensile strengths in the range of 48–86 MPa, tensile modulus in the range of 1.25–2.22 GPa and elongation at break in the range of 3–37%. Electrical insulating properties of some polymer films were evaluated on the basis of dielectric constant and dielectric loss and their variation with frequency and temperature. The values of the dielectric constant at 10 kHz were in the range of 2.94–3.08 for polyimides and 3.89–4.49 for poly(imide‐amide)s. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3062–3068, 2006     

Dielectric properties of graphene–iron oxide/polyimide films with oriented graphene

The preparation of high‐dielectric‐constant (k) materials is important in the field of electronics. However, how to effectively use the function of fillers to enhance k is still a challenge. In this study, anisotropic graphene (GNS)–iron oxide (Fe₃O₄)/polyimide (PI) nanocomposite films with oriented GNSs were prepared by the in situ polymerization of 4,4′‐oxydianiline and pyromellitic anhydride in the presence of GNS–Fe₃O₄. Films of the precursors were fabricated, and this was followed by stepwise imidization under a magnetic field at a higher temperature to orient the magnetic sheets. The orientation of GNS–Fe₃O₄ and the relationships of the GNS–Fe₃O₄ content and measurement frequency with the dielectric properties of the GNS–Fe₃O₄/PI films were studied in detail. The dielectric property differences of the GNS–Fe₃O₄/PIs with GNS–Fe₃O₄ parallel or perpendicular to the film surface were not obvious, when the content of GNS–Fe₃O₄ was lower than 5 wt %. However, at the percolation threshold, the k values of GNS–Fe₃O₄/PI films with horizontal GNS–Fe₃O₄ were much higher than those of the other two kinds of films at 10³ Hz; this was derived from the contribution of more effective microcapcitors parallel to the film surface. So, making the GNS–Fe₃O₄ parallel to the film surface greatly enhanced k of GNS–Fe₃O₄. However, switching the charges on the large lateral surface of the parallel GNSs with the electric field also caused a higher dielectric loss and the frequency dependence of k and the dielectric loss at low frequency. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43041.     

Pyroelectric and dielectric properties of spin‐coated thin films of vinylidene fluoride–trifluoroethylene copolymers

This work emphasizes the use of vinylidene fluoride and trifluoroethylene copolymer P(VDF‐TrFE) as a pyroelectric sensor. The pyroelectric and dielectric properties of the copolymer have been investigated in the temperature interval 150–350 K. The samples were prepared by using a spin‐coating technique with 70/30 mol% VDF/TrFE copolymer. The final film thickness of the samples, which is mainly determined by the concentration of the copolymer, spinning rate and spin time, was measured with a surface profiler. The samples were annealed at 150 °C for 10 min to improve the crystallinity of the copolymer. The crystallinity of the annealed and non‐annealed samples was compared by IR spectroscopy. The most effective process by which to improve the pyroelectric response of the material is to pole the sample with huge poling field‐strengths at elevated temperatures. Both pyroelectric and dielectric activities of the samples were measured after each successful poling process. It was observed that while the pyroelectric activity of the material increases, the dielectric activity decreases, so the figure‐of‐merit of the material, which shows the sensor capability of the material, was increased by a significant amount. It was found that the pyroelectric coefficient of VDF/TrFE (70/30 mol%) copolymer is 68.7 µC m^?2 K^?1 at 300 K. © 2001 Society of Chemical Industry     

Organosoluble,low‐dielectric‐constant fluorinated polyimides based on 9,9‐bis[4‐(4‐amino‐2‐trifluoromethyl‐ phenoxy)phenyl]xanthene

A new trifluoromethylated bis(ether amine) monomer, 9,9‐bis[4‐(4‐amino‐2‐trifluoromethylphenoxy)phenyl]xanthene (BATFPX), was prepared through the nucleophilic aromatic substitution reaction of 2‐chloro‐5‐nitrobenzotrifluoride and 9,9‐bis(4‐hydroxyphenyl)xanthene in the presence of potassium carbonate, followed by catalytic reduction with hydrazine and Pd/C in ethanol. A series of novel fluorinated polyimides were synthesized from BATFPX with various commercially available aromatic tetracarboxylic dianhydrides by one‐step polycondensation in m‐cresol. The resulting polyimides were readily soluble in many organic solvents such as N,N‐dimethylacetamide and tetrahydrofuran, and afforded transparent, flexible and strong films with low moisture absorption (0.28–0.51%), low dielectric constant (2.85–3.26 at 1 MHz) and good optical transparency with UV‐visible absorption cut‐off wavelengths at 352–410 nm. All the polyimides were amorphous and exhibited high thermal stability, with glass transition temperatures of 282–330 °C, 5% weight loss temperatures above 520 °C in nitrogen or air and char yields higher than 55% at 800 °C in nitrogen. Also, these polyimides had good mechanical properties with tensile strengths of 93–118 MPa, elongations at break of 9–16% and initial moduli of 2.07–2.58 GPa. Copyright © 2011 Society of Chemical Industry     

Preparation of siloxane–silsesquioxane hybrid thin films for large‐scale‐integration interlayer dielectrics with excellent mechanical properties and low dielectric constants

Several kinds of homogeneous organic–inorganic hybrid polymer thin films were designed with improved mechanical properties and low dielectric constants (<3.0). Novel soluble siloxane–silsesquioxane hybrid polymers were synthesized with cyclic and/or cage silane monomers, which had triorganosiloxy (R₃Si_1/2), diorganosiloxane (R₂SiO_2/2), and organosilsesquioxane (RSiO_3/2) moieties with ethylene bridges at the molecular level, by the hydrolysis and condensation of 2,4,6,8‐tetramethyl‐2,4,6,8‐tetra(trimethoxysilylethyl)cyclotetrasiloxane (a cyclic monomer). The electrical properties of these films, including the dielectric constant (～2.51), leakage current (6.4 × 10^?11 A/cm² at 0.5 MV/cm), and breakdown voltage (～5.4 MV/cm) were fairly good. Moreover, the mechanical properties of the hybrid films, including the hardness (～7 GPa), modulus (～1.2 GPa), and crack‐free thickness (<2 μm), were excellent in comparison with those of previous spin‐on‐glass materials with low dielectric constants. The excellent mechanical properties were proposed to be due to the high contents of Si? OH groups (>30%) and the existence of ethylene bridge and siloxane moieties in the hybrid polymer precursors. In addition, the mechanical properties of the hybrid films were affected by the contents of the cagelike structures. The more cagelike structures a hybrid film contained, the worse its mechanical properties were. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 626–634, 2003     

Poly(ether imide)s containing cyano substituents and thin films made from them

A series of poly(ether imide)s containing functional cyano groups has been prepared by polycondensation reaction of 2,6‐bis(m‐aminophenoxy)benzonitrile with different bis(ether dianhydride)s, such as 2,2‐bis[4‐(3,4‐dicarboxyphenoxy)phenyl]isopropane dianhydride, 2,2‐bis[4‐(3,4‐dicarboxyphenoxy)‐phenyl]hexafluoroisopropane dianhydride, 1,1‐bis[4‐(3,4‐dicarboxyphenoxy)phenyl]cyclohexane dianhydride, and 3,3‐bis[4‐(3,4‐dicarboxyphenoxy) phenyl]phthalide dianhydride. The polymers were soluble in polar aprotic solvents and even in less polar solvents and were processed into thin films by casting their solutions. The properties of the polymers, particularly the crosslinking of macromolecular chains through cyano groups, were studied by using dynamic mechanical analysis (DMA), thermal stability, glass transition, and solubility measurements. Also, the molecular relaxations were evidenced by DMA and dielectric spectroscopy. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Thickness‐dependent domain wall reorientation in 70/30 lead magnesium niobate‐ lead titanate thin films

Continued reduction in length scales associated with many ferroelectric film‐based technologies is contingent on retaining the functional properties as the film thickness is reduced. Epitaxial and polycrystalline lead magnesium niobate‐lead titanate (70PMN‐30PT) thin films were studied over the thickness range of 100‐350 nm for the relative contributions to property thickness dependence from interfacial and grain‐boundary low permittivity layers. Epitaxial PMN‐PT films were grown on SrRuO₃/(001)SrTiO₃, while polycrystalline films with {001}‐Lotgering factors >0.96 were grown on Pt/TiO₂/SiO₂/Si substrates via chemical solution deposition. Both film types exhibited similar relative permittivities of ~300 at high fields at all measured thicknesses with highly crystalline electrode/dielectric interfaces. These results, with the DC‐biased and temperature‐dependent dielectric characterization, suggest irreversible domain wall mobility is the major contributor to the overall dielectric response and its thickness dependence. In epitaxial films, the irreversible Rayleigh coefficients reduced 85% upon decreasing thickness from 350 to 100 nm. The temperature at which a peak in the relative permittivity is observed was the only measured small signal quantity which was more thickness‐dependent in polycrystalline than epitaxial films. This is attributed to the relaxor nature present in the films, potentially stabilized by defect concentrations, and/or chemical inhomogeneity. Finally, the effective interfacial layers are found to contribute to the measured thickness dependence in the longitudinal piezoelectric coefficient.     

Preparation and properties of layered silicate/polyimide hybrid films

Layered silicate/polyimide (PI) hybrid films were prepared from 4,4′‐oxydianiline, 3,3′,4,4′‐oxydiphthalic anhydride, and chemically modified montmorillonite via an in situ intercalation polymerization pathway. The X‐ray diffraction and transmission electron microscopy results indicated that the silicates were homogeneously dispersed as exfoliated layers in the PI hybrid film with 2% silicate. The mechanical properties and thermal stabilities of the PI hybrid films changed with the content of the layered silicates. The coefficient of thermal expansion and water uptake of the PI hybrid films decreased with increasing silicate contents because of the barrier effect of platelike silicate layers, which prevented the diffusion and penetration of water. The dielectric strength and electrical aging performance of the PI hybrid films could also be improved as the silicate layer highly dispersed in the films. For the hybrid PI film with 5% layered silicate, the time to failure during electrical aging exceeded 280 h, which was 2.5 times as long as that of pure PI film. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1176–1183, 2005     

Enhanced thermal and electrical insulation properties of polyimide films determined via a two‐dimensional layered double hydroxide–potassium perfluorooctane sulfonate material

Polyimide (PI) films used in aerospace and rail applications are degraded by thermal, chemical, and electric power under the effect of insulation aging. To prevent these types of degradation, we prepared nanocomposite films of PI and layered double hydroxide (LDH) modified with the potassium perfluorooctane sulfonate (FS) by an in situ method. On the whole, the glass‐transition temperature, dielectric constant (?′), and corona‐resistance lifetime of the nanocomposite films increased over those of the pure PI film, but the temperature at 10 wt % weight loss, breakdown strength, and volume resistance decreased correspondingly as a whole. The PI matrix was protected by the inorganic material of LDH–FS with a high ?′ from corona corrosion. Furthermore, the heat and chemical interactions of the composite films improved the corona‐resistance lifetime, despite the decrease in the breakdown strength; this should result in promising applications for insulation parts of variable‐frequency motors. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46528.     

Electrical properties of conventional polyimide films: Effects of chemical structure and water uptake

A series of conventional polyimide (CPI) films, based on pyromellitic dianhydride (PMDA) and benzophenonetetracarboxylicdianhydride (BTDA), were prepared by a two step process, and their dielectrical constant, dielectrical loss, and DC conduction behaviors were studied at different frequencies and voltages. Their dielectrical breakdown voltage, water uptake, and solubility properties were also investigated. The effects of chemical structure and water uptake on the electrical properties of the films are discussed in detail. The dielectric constants of the CPI films vary between 2.93 and 3.72 at 1 MHz frequency and they are in the following decreasing order: BTDA‐DDS > BTDA‐DDE > PMDA‐DDS > PMDA‐DDE. The structure and thermal and oxidative stability of films were analyzed by FTIR‐ATR and TGA, respectively. The results showed that all CPI films have good insulating properties, such as high dielectric breakdown voltage, low dielectric constant with stability for long period of frequency, and low leakage density. Our results concerning electrical properties also suggest that electron hopping is responsible for AC conduction and Poole‐Frenkel mechanism is predominant for DC conduction of all CPI films. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 810–818, 2006     

Thermal and electrical behaviour of some hybrid polyimide films containing barium and titanium oxides

Aromatic polyimides are high‐performance polymers used in applications demanding service at enhanced temperature while maintaining their structural integrity and excellent combination of chemical, physical and mechanical properties. The incorporation of various metallic additives into a polyimide matrix improves its properties, leading to materials required by specific applications. Hybrid polyimide films containing barium and titanium oxides having thicknesses in the range of tens of micrometres were prepared. These films were obtained using the sol–gel technique starting from a poly(amic acid) and a soluble precursor of metal oxides. They exhibited good thermal stability having an initial decomposition temperature above 460 °C, and a glass transition temperature in the range 217–238 °C. Two subglass transitions, γ and β, were evident from dynamic mechanical analysis and dielectric spectroscopy. A study of the thermal and electrical behaviour of some hybrid polyimide films containing barium and titanium oxides is presented. On increasing the concentration of metal oxides, an increase of dielectric constant and a decrease of thermal stability of the hybrid films were observed. The presence of metal oxides shifted the glass transition temperature and the temperature of the β transition to higher values. Copyright © 2009 Society of Chemical Industry     

Development of flame retardancy properties of new halogen‐free phosphorous doped SiO2 thin films on fabrics

In this study, flame retardancy properties of fabrics treated with phosphorous (P) doped and undoped SiO₂ thin films were developed by sol–gel technique. As to this aim, P‐doped and undoped SiO₂ film were coated on cotton fabric from the solutions prepared from P, Si‐based precursors, solvent, and chelating agent at low temperature in air using sol–gel technique. To determine solution characteristics, which affect thin film structure, turbidity, pH values, and rheological properties of the prepared solutions were measured using a turbidimeter, a pH meter, and a rheometer machines before coating process. The thermal, structural, and microstructural characterization of the coating were done using differential thermal analysis/thermograviometry, fourier transform infrared spectroscopy, X‐ray diffractometry, and scanning electron microscopy. In addition, tensile strength, wash fastness, flame retandancy, and lightness properties of the coated fabrics were determined. To compensate the slight loss of tensile strength of samples, which occurred at the treated fabrics with P‐doped Si‐based solutions, the cotton fabrics were coated with polyurethane films during second step. In conclusion, the flame retardant cotton fabric with durability of washing as halogen‐free without requiring after treatment with formaldehyde was fabricated using sol–gel processing for the first time. Moreover the cotton fabrics, which were treated with P‐doped Si‐based solutions and then coated with polyurethane at second step, still has got nonflammable property. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

The effect of titania content on the physical properties of polyimide/titania nanohybrid films

In this study, a series of PI/TiO₂ nanohybrid materials were prepared from polyamic acid of 3,3′,4,4′-benzophenonetetracarboxylic dianhydride/3,3′-diaminodiphenyl sulfone, and titania precursor by the sol-gel method. The titania content in the hybrid system was varied from 0 to 5 wt %. The physical and mechanical properties of the hybrids such as refractive index, optical transmission, and tensile strength were investigated. It was determined that incorporation of titania precursor into the PI matrix improved the refractive indices and tensile modulus of the hybrid films. It was observed that the optical transmittance and tensile strength of the nanohybrids were slightly decreased with the increasing titania content. It was determined that the hybrid films might have enhanced the UV shielding properties compare to the PI films. Furhermore, the hybrid materials showed better thermal stability than the PI. SEM studies demonstrated that titania particles (1 and 3 wt %) were distributed homogeneously through the PI matrix. The effect of the titania content in the PI on DC conductivity and dielectric constant were also analyzed. For the PI film containing 5 wt % titania, activation energy value increased to 1.0 eV from the value of 0.65 eV. DC conductivity value of the films depending on titania content varied between 3.0 × 10⁻¹¹ and 1.4 × 10⁻¹⁰ S/cm at room temperature. Relative dielectric constants of the films were calculated from capacitance measurements depending on frequency (40–100 kHz) at different temperatures (303–360 K). The values increased with the increasing titania content. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012