Chemical synthesis of highly stable PVA/PANI films for supercapacitor application

Polyvinyl alcohol (PVA)/polyaniline (PANI) thin films were chemically synthesized by adopting two step process: initially a thin layer (200 nm) of PVA was spin coated by using an aqueous PVA solution onto fluorine doped tin oxide (FTO) coated glass substrate, afterwards PANI was chemically polymerized from aniline monomer and dip coated onto the precoated substrate. The thickness of PANI layer was varied from 293 nm to 2367 nm by varying deposition cycles onto the precoated PVA thin film. The resultant PVA/PANI films were characterized for their optical, morphological and electrochemical properties. The FT-IR and Raman spectra revealed characteristic features of the PANI phase. The SEM study showed porous spongy structure. Electrochemical properties were studied by electrochemical impedance measurement and cyclic voltammetry. The electrochemical performance of PVA/PANI thin films was investigated in 1 M H₂SO₄ aqueous electrolyte. The highest specific capacitance of 571 Fg⁻¹ was observed for the optimized thickness of 880 nm. The film was found to be stable for more than 20,000 cycles. The samples degraded slightly (25% decrement in specific capacitance) for the first 10,000 cycles. The degradation becomes much slower (10.8% decrement in specific capacitance) beyond 10,000 cycles. This dramatic improvement in the electrochemical stability of the PANI samples, without sacrificing specific capacitance was attributed to the optimized PVA layer.     

Study on field emission and photoluminescence properties of ZnO/graphene hybrids grown on Si substrates

Zinc oxide/graphene (ZnO/G) hybrids are prepared on n-Si (1 0 0) substrates by electrophoretic deposition and magnetron sputtering technique. The crystal structure, morphology and photoluminescence (PL) properties of the ZnO/G hybrids are analyzed via X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) and fluorescence–phosphorescence spectrometer, respectively. The results indicate that the crystal quality of ZnO nanostructure deteriorates after depositing graphene buffer layer. Whereas many three dimensional stacking blowballs form in the ZnO/G hybrid, creating a larger surface area than that of ZnO nanostructure. The photoluminescence (PL) spectrum of the ZnO/G hybrid contains multi-peaks, which are consistent with ZnO nanostructure except for two new peaks at 390 and 618 nm. In addition, field emission measurement reveals that E_to and E_thr decrease from 8.01 V μm⁻¹ and 14.90 V μm⁻¹ of the ZnO nanostructure to 2.72 V μm⁻¹ and 7.70 V μm⁻¹ of the ZnO/G hybrid. ZnO/G hybrid is characteristic of having excellent emitting behavior suitable for application in field emission technology.     

Sol–gel derived composite from bioactive glass–polyvinyl alcohol

Investigation of novel biomaterials for bone engineering is based on the development of porous scaffolds, which should match the properties of the tissue that is to be replaced. These materials need to be biocompatible, ideally osteoinductive, osteoconductive, and mechanically well-matched. In the present paper, we report the preparation and characterization of hybrid macroporous scaffold of polyvinyl alcohol (PVA)/bioactive glass through the sol–gel route. Hybrids containing PVA (80, 70 and 60 wt%) and bioactive glass with composition 58SiO₂–33CaO–9P₂O₅ were synthesized by foaming a mixture of polymer solution and bioactive glass via sol–gel precursor solution. PVA with two different degree of hydrolysis (DH), 98.5% (high degree) and 80% (low degree) were also investigated, in order to evaluate the influence of residual acetate group present in polymer chain on the final structure and properties of 3D porous composite produced. The microstructure, morphology and crystallinity of the hybrid porous scaffolds were characterized by X-ray diffraction (XRD), Infrared Fourier Transform spectrometry (FTIR) and Scanning electron microscopy (SEM/EDX) analysis. In addition, specific surface area was assessed by B.E.T. nitrogen adsorption method and mechanical behavior was evaluated by compression tests. Preliminary cytotoxicity and cell viability were also performed by the MTT assay. VERO cell monolayers were grown in 96-well microtiter plates. The results have clearly showed that hybrid foams of polyvinyl alcohol/bioactive glass (PVA/BG) with interconnected macroporous 3D structure were successfully produced. All the tested hybrids of PVA/BG have showed adequate cell viability properties for potential biological applications.     

Templated growth of superparamagnetic iron oxide nanoparticles by temperature programming in the presence of poly(vinyl alcohol)

Magnetite (Fe₃O₄) nanostructures with different morphologies including uniform nanoparticles, magnetic beads and nanorods were synthesized via a co-precipitation method. The synthesis process was performed at various temperatures in the presence of polyvinyl alcohol (PVA) at different concentrations. It is shown that small amounts of PVA act as a template in hot water (70 °C), leading to the oriented growth of Fe₃O₄ nanorods, which was confirmed by selected area electron diffraction. Individually coated magnetite nanoparticles and magnetic beads were formed at a relatively lower temperature of 30 °C in the folded polymer molecules due to the thermo-physical properties of PVA. When a moderate temperature (i.e. 50 °C) was used, nanorods and nanobeads co-existed. At higher concentrations of PVA (polymer/iron mass ratio of 5), however, the formation of magnetic beads was favored. The nanorods were shown to be unstable upon exposure to electron beams. Freezing/thawing process was applied post synthesis as temperature programming to fabricate stable nanorods with rigid walls.     

Non-cytotoxic organic–inorganic hybrid bioscaffolds: An efficient bedding for rapid growth of bone-like apatite and cell proliferation

Synthesis and characterization of organic–inorganic macroporous hybrid scaffolds were investigated. The materials were prepared by combining 2-hydroxyethylmethacrylate (HEMA) and triethoxyvinylsilane (TEVS) chemically modified by Ca^2 + and PO₄^3 ? ions via sol–gel route. In this study we have constructed a sugar-based cracks-free three-dimensional (3D) network with interconnected porous architecture within the range of 150–300 μm and rough topography. The obtained results revealed that both topography and composition of prepared materials allow rapid growth of the bone-like apatite (HAp) layer on their surface after soaking in biological medium. Preliminary studies have shown that hybrids covered by HAp are non-cytotoxic and allow cell proliferation that make them a promising scaffolds in the field of bone regenerative medicine. The materials were mainly characterized by powder X-ray diffraction analysis (PXRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy–energy-dispersive spectroscopy (SEM–EDS) and transmission electron microscopy–energy-dispersive spectroscopy (TEM–EDS).     

Biodegradable and bioactive properties of a novel bone scaffold coated with nanocrystalline bioactive glass for bone tissue engineering

The development of the new technologies of bone tissue engineering requires the production of bioactive and biodegradable macroporous scaffolds. Hydroxyapatite (HA) ceramics are useful bone substitutes, but they degrade minimally. Tricalcium phosphates also show poor ability of Ca-P formation both in-vitro and in-vivo, although they are degradable. The present study introduces a biodegradable, bioactive, and macroporous scaffold with suitable mechanical properties. The prepared hydroxyapatite scaffold was coated with a nanocrystalline bioactive glass layer to be subsequently sintered at different temperatures. The bioactivity and degradability of the coated scaffolds were investigated by standard procedures. The ability to induce Ca-P formation in SBF (simulated body fluid) was also investigated semi-quantitatively. BS1 scaffolds (scaffolds sintered at 800 °C with a holding time of 2 h) showed remarkable bioactivity and degradability simultaneously. Formation of a nanocrystalline phase (Si₂PO₇) during the sintering considerably decreased the capability of BS1 scaffolds for Ca-P formation and the rate of degradation but enhanced their mechanical properties. The BS1 scaffolds showed not only significant bioactivity but also good degradability and suitable mechanical property.     

Oxidation of polyvinyl alcohol by persulfate activated with heat,Fe, and zero-valent iron

The oxidation of polyvinyl alcohol (PVA) by persulfate (S₂O₈²⁻) activated with heat, Fe²⁺, and zero-valent iron (Fe(0)) was investigated via batch experiments. It was hypothesized that elevated temperature and the addition of Fe²⁺ or Fe(0) into a persulfate-water system could enhance the oxidation of PVA by activated persulfate. Increasing the temperature from 20 to 60 °C or 80 °C accelerated the oxidation rate of PVA, which achieved complete oxidation in 30 and 10 min, respectively. At 20 °C, the addition of Fe²⁺ or Fe(0) to the persulfate-water system significantly enhanced the oxidation of PVA. The optimal persulfate-to-Fe²⁺ or Fe(0) molar ratio was found to be 1:1. Complete oxidation of PVA was obtained by Fe(0)-activated persulfate in 2 h. Synergistic activation of persulfate by heat and Fe²⁺ or Fe(0) was also shown to enhance the oxidation of PVA in the persulfate-water system. By using GC–MS analysis, an oxidation product of PVA was identified as vinyl acetic acid (C₄H₆O₂), which is readily biodegradable. Our results suggest that the oxidative treatment of PVA by activated persulfate is a viable option for the pretreatment of PVA-laden wastewater to enhance its biodegradability.     

Photocatalytic degradation of phenol in aqueous solutions by Pr-doped TiO2 nanoparticles

Photocatalytic degradation of phenol in water was examined using Pr-doped TiO₂ nanoparticles. These photocatalysts were synthesized by an acid-peptized sol–gel method from titanium tetra-isopropoxide with different concentrations of Pr(III) dopant and calcination temperatures. Several tools such as XRD, BET surface area, SEM, and EDX, were used to evaluate particle structure, size distribution, and composition. The optical absorption properties of the prepared particles were also measured. Photocatalytic activity of the particles was studied in a batch reactor containing phenol solution with 400 W UV irradiation. Parameters affecting photocatalytic process such as the catalyst crystallinity, light absorption efficiency, the dosage of catalyst, dopant and phenol concentrations were investigated. The Pr-doped TiO₂ showed high activity for photocatalytic degradation of phenol. The presence of Pr ions in the TiO₂ particles would cause a significant absorption shift towards the visible region. The degradation process was optimized using 1 g/L Pr-doped TiO₂ with a Pr(III) concentration of 0.072 mol% after 2 h irradiation. It was shown that photodegradation followed a pseudo-first-order kinetics and the rate constant changed with phenol concentration.     

Preparation and characterization of oxidized alginate covalently cross-linked galactosylated chitosan scaffold for liver tissue engineering

Liver tissue engineering (LTE) requires a perfect extracellular matrix (ECM) for hepatocytes culture to maintain high level of liver-specific functions. Here, we reported a LTE scaffold derived from oxidized alginate covalently cross-linked galactosylated chitosan via Schiff base reaction, without employing any extraneous chemical cross-linking agent. The structure of galactosylated chitosan (GC) and oxidized alginate was confirmed by Fourier transformed infrared (FTIR) spectra, proton nuclear magnetic resonance (¹H-NMR) spectroscopy, X-ray diffraction (XRD) or thermogravimetric (TG) analysis. The structure and properties of a series of the scaffolds were characterized by FTIR, XRD, scanning electron microscopy (SEM), porosity, equilibrium swelling, mechanical properties, thermal stability and in vitro degradation. FTIR spectra confirmed the characteristic peak of Schiff base groups in the scaffolds and XRD indicated the scaffolds could be amorphous. SEM analysis showed that the scaffolds displayed highly porous surfaces with average pore size of 50-150 μm and interconnected pore structure in the internal structure with average pore size of 100-250 μm. Porosity measurement suggested the scaffolds had a porosity of about 70%. The compressive modulus of the scaffolds (hydrated) was in the range of 4.2-6.3 kPa. Further studies showed that, with the increase of the oxidized alginate content, the equilibrium swelling and in vitro degradation rate of the scaffolds decreased and the thermal stability slightly increased, which might mainly attribute to the difference of the degree of cross-linking and the nature properties of the raw materials. Additionally, the biocompatibility of the scaffolds was evaluated in vitro. The results showed that the hepatocytes cultured on the scaffolds had a typical spheroidal morphology, formed multi-cellular aggregates and presented perfect integration with the scaffolds, which suggested that the scaffolds may be potential candidates for LTE strategies.     

Degradation behavior of hydrophilized PLGA scaffolds prepared by melt-molding particulate-leaching method: Comparison with control hydrophobic one

Porous PLGA/PVA scaffolds as hydrophilized PLGA scaffolds for tissue engineering applications were fabricated by a novel melt-molding particulate leaching method (non-solvent method). The prepared scaffolds exhibited highly porous and open-cellular pore structures with almost same surface and interior porosities (pore size, 200–300 μ m; porosity, about 90%). The in vitro degradation behavior of the PLGA and PLGA/PVA scaffolds was compared at 37^∘C in PBS (pH 7.4) with and without the solution change everyday to see the effect of solution pH as well as scaffold hydrophilicity on the degradation behavior. The changes in dimension, molecular weight, mechanical properties (maximum load and modulus), and morphology of the scaffolds were examined with degradation time. The degradation behavior of the PLGA and PLGA/PVA scaffolds was further investigated in vivousing a rat model (subcutaneously implantation). It was observed that both PLGA and PLGA/PVA scaffolds in decreasing pH condition (PBS no change) showed faster degradation than those in constant pH condition (PBS change everyday), owing to the enhanced intramolecular depolymerization by the increment of chain hydrophilicity caused by carboxylate groups as well as the autocatalysis of carboxylic acids accumulated in the solution by the cleavage of PLGA backbone ester bonds. The scaffolds in vivo condition also showed faster degradation than those in vitro, probably due to the aid of foreign body giant cells or enzymes. The PLGA/PVA scaffold showed slightly faster degradation than the PLGA scaffold for both in vitro and in vivo conditions. Author to whom all correspondence should be addressed.     

One-step synthesis of Fe-phthalocyanine/Fe3O4 hybrid microspheres

Fe-phthalocyanine/Fe₃O₄ hybrid microspheres were synthesized from bis-phthalonitrile and FeCl₃·6H₂O through a simple and effective solvent-thermal route. The hybrids were monodispersed solid microspheres with diameter of ~ 400 nm. The ferromagnetic signature emerged with the saturated magnetization of ~ 55.7 emu g⁻¹, and the coercive force of ~ 93.7 Oe at 300 k. The addition of bis-phthalonitrile oligomer brought Fe₃O₄ nanoparticles novel dielectric property: a new dielectric loss peak appeared at ~ 8 GHz. Considering the microwave magnetic loss properties, two microwave magnetic loss peaks were presented at ~ 1.5 GHz and ~ 10 GHz, the former peak was attributed to the natural properties of the Fe₃O₄, and the latter originated from the interface effects between the bis-phthalonitrile oligomer and Fe₃O₄.     

Low-temperature processing of transparent conductive indium tin oxide nanocomposites using polyvinyl derivatives

We report on the influence of additives on the electrical, optical, morphological and mechanical properties of transparent conductive indium tin oxide (In₂O₃:Sn; ITO) nanoparticle films by the use of polymers as matrix material. Key issues to fabricate layers suitable for use in electronic device applications are presented. Polyvinyl derivatives polyvinyl acetate, polyvinyl alcohol (PVA) and polyvinyl butyral were applied and their suitability to form transparent conductive ITO nanocomposite coatings at a maximum process temperature of 130 °C was investigated. A low-temperature treatment with UV-light has been developed to provide the possibility of curing ITO thin films deposited on substrates which do not withstand high process temperatures. Compared to best pure ITO layers (0.2 Ω^− 1 cm^− 1), the ITO-PVA nanocomposite coatings show a conductance value of 4.1 Ω^− 1 cm^− 1 and 5.9 Ω^− 1 cm^− 1 after reducing in forming gas. Sheet resistance of ca. 1200 Ω/□ with coexistent transmittance of 85% at 550 nm for a layer thickness of about 1.45 μm was achieved. The conductance enhancement is a consequence of nanoparticulate ITO network densification due to the acting shrinkage forces caused by the polymer matrix during film drying and additionally UV-induced crosslinking of PVA.     

Orientation of B-C-N hybrid films deposited on Ni (111) and polycrystalline Ti substrates explored by X-ray absorption spectroscopy

Orientation of sp²-bonded boron carbonitride (BCN) hybrid films has been investigated. The films were synthesized on Ni (111) and polycrystalline Ti substrates by radio frequency plasma enhanced chemical vapor deposition using tris-dimethylamino borane as a single-source molecular precursor. The deposition was performed at the radiofrequency power 400-800 W at the working pressure 2.6 Pa. Formation of sp²-BCN hybrids in the samples was confirmed by X-ray diffraction (XRD). In the XRD profile, the peak at 26.3° revealed formation of crystalline phase in the samples in which the lattice planes are separated from each other by around 3.5 Å. The D band at ~ 1350 cm^− 1 and the G band at ~ 1570 cm^− 1 in Raman spectra also suggested presence of graphite-like sp²-B-C-N hybrid bonds. The films were composed of different B-N, B-C, and C-N bonds to form sp²-BCN atomic hybrids confirmed by X-ray photoelectron spectra. Orientation and local structures of the films were studied by near-edge X-ray absorption fine structure (NEXAFS) measurements. The dominant presence of π* and σ* resonance peaks of the sp² hybrid orbitals in B K-edge NEXAFS spectra revealed preferred formation of sp²-BCN atomic hybrids around B atoms like-BN₃ configuration in respect to the plane of Ni (111) substrate. Different orientations were suggested on the basis of polarization dependence of B K-edge and N K-edge of the NEXAFS spectra.     

Synthesis of BaTiO3 nanoparticle/poly(2-hydroxyethyl methacrylate) hybrid nanofibers via electrospinning

BaTiO₃ nanoparticle/poly(2-hydroxyethyl methacrylate) (PHEMA) hybrid nanofibers were fabricated from an in situ synthesized BaTiO₃ nanoparticle/polymer hybrid by electrospinning. The bulk hybrid for nanofibers was synthesized through the in situ hydrolysis of Ba–Ti alkoxide modified with 2-vinyloxyethanol and subsequent copolymerization with HEMA monomer. IR and ¹³C NMR spectra showed the formation of polymer matrix. The molecular weights of BaTiO₃ nanoparticle/PHEMA hybrid for spinning were 1.3 × 10⁵ for 20 equiv. PHEMA and 5.7 × 10⁵ for 30 equiv. PHEMA. The crystallite size of BaTiO₃ particles in the hybrid was 4.5 nm according to the Scherrer equation. The diameter of BaTiO₃ nanoparticle/PHEMA hybrid nanofibers ranged from 500 nm to 1 μm. A field stress–strain curve was observed for the BaTiO₃ nanoparticle/PHEMA hybrid nanofiber.     

Highly porous titanium (Ti) scaffolds with bioactive microporous hydroxyapatite/TiO2 hybrid coating layer

Highly porous Ti scaffolds with a bioactive microporous hydroxyapatite (HA)/TiO₂ hybrid coating layer were fabricated using the sponge replication process and micro-arc oxidation (MAO) treatment to produce the porous Ti scaffold and hybrid coating layer, respectively. In particular, the morphology and chemical composition of the hybrid coating layer were controlled by carrying out the MAO treatment in electrolyte solutions containing various concentrations of HA, ranging from 0 to 30 wt.%. The fabricated sample showed high porosity of approximately 70 vol.% with interconnected pores and reasonably high compressive strength of 18 ± 0.3 MPa. Furthermore, the surfaces could be coated successfully with a bioactive microporous HA/TiO₂ hybrid layer. The amount of HA particles in the hybrid coating layer increased with increasing HA content in the electrolyte solution, while preserving the microporous morphology. This hybrid coating improved the osteoblastic activity of the porous Ti scaffolds significantly.     

The effect of perfusion culture on proliferation and differentiation of human mesenchymal stem cells on biocorrodible bone replacement material

Biocorrodible iron foams were coated with different calcium phosphate phases (CPP) to obtain a bioactive surface and controlled degradation. Further adhesion, proliferation and differentiation of SaOs-2 and human mesenchymal stem cells were investigated under both static and dynamic culture conditions. Hydroxyapatite (HA; [Ca₁₀(PO₄)₆OH₂]) coated foams released 500 μg/g iron per day for Dulbecco's modified eagle medium (DMEM) and 250 μg/g iron per day for McCoys, the unmodified reference 1000 μg/g iron per day for DMEM and 500 μg/g iron per day for McCoys, while no corrosion could be detected on brushite (CaHPO₄) coated foams. Using a perfusion culture system with conditions closer to the in vivo situation, cells proliferated and differentiated on iron foams coated with either brushite or HA while in static cell culture cells could proliferate only on Fe-brushite. We conclude that the degradation behaviour of biocorrodible iron foams can be varied by different calcium phosphate coatings, offering opportunities for design of novel bone implants. Further studies will focus on the influence of different modifications of iron foams on the expression of oxidative stress enzymes. Additional information about in vivo reactions and remodelling behaviour are expected from testing in implantation studies.     

Synthesis of high quality TiO2 membranes on alumina supports and their photocatalytic activity

This study describes the synthesis of TiO₂ membranes on alumina supports by the spin-coating technique using the sol-gel method with water-soluble chitosan (WSC) as an additive. After calcining the sample at 500 °C, the WSC was completely decomposed, and the remaining membrane consisted mainly of anatase. Controlling the amount of WSC in the TiO₂ sol to within a range of 0.1 wt.%-0.3 wt.% resulted in TiO₂ membranes on alumina supports with enhanced structural and catalytic properties. These properties included a high surface area (164 m²/g-116 m²/g) and porosity (47.3%-52.2%), homogeneity without cracks and pinholes, thinness (0.8 μm), as well as high degradation of methyl orange (61.2%-49.2%).     

Small-angle X-ray scattering and FTIR characterization of nanostructured poly (vinyl alcohol)/silicate hybrids for immunoassay applications

In the present work we aimed to develop and characterize hybrid organic–inorganic materials based on poly(vinyl alcohol) (PVA) polymer chemically modified by organosilanes and crosslinked network to be tested as solid support on immunoassay application. Hybrids were synthesized by reacting PVA with 5 different alkoxysilanes modifying chemical groups: tetraethoxysilane (TEOS), 3-mercaptopropyltriethoxysilane (MPTES), 3-glycidoxypropyltrimethoxysilane (GPTMS), 3-(triethoxysilyl)propylisocyanate (TESPI), and 3-aminopropyltriethoxysilane (APTES). PVA-derived hybrids were also modified by chemically crosslinking with glutaraldehyde (GA) during the synthesis reaction. In order to investigate the structure in the nanometer-scale, PVA-derived hybrids were characterized by using small-angle X-ray scattering synchrotron radiation (SAXS). Fourier transform infrared spectroscopy (FTIR) was used to investigate PVA hybrids chemical functionalities and their interaction with bovine herpesviruses. The morphology of silane modified PVA films were also analyzed by SEM coupled to EDX. The bioactivity assays were tested through Enzyme Linked Immunosorbent Assay (ELISA) with bovine herpesvirus (BoHV). SAXS results have indicated nano-ordered disperse domains for PVA hybrids with different X-ray scattering patterns for PVA polymer and PVA-derived hybrids. FTIR spectra have clearly showed that the proposed modifications of PVA by organosilanes were obtained. The chemical crosslinking of PVA polymer chain by GA was verified by FTIR. The immunoassay results have showed that PVA hybrids with chemically functionalized structures have played an important role on regulating to some extent the interaction of herpesvirus and solid substrate at the interface. These results have given strong evidence that PVA-derived hybrid nanocomposites were successfully formed with GA crosslinked network. Also, such PVA based material could be advantageously used in immunoassays with enhanced specificity for diagnosis.     

Characterization of (K0.5Na0.5)NbO3 powders and ceramics prepared by a novel hybrid method of sol–gel and ultrasonic atomization

(K_0.5Na_0.5)NbO₃ powders and ceramics were prepared by a novel hybrid method of sol–gel and ultrasonic atomization, in which Nb₂O₅ was used as the niobium source to replace those expensive soluble niobium salts. X-ray diffraction and thermal analysis were performed to investigate the synthesis process and phase transformation behavior of (K_0.5Na_0.5)NbO₃ powders. The results showed that (K_0.5Na_0.5)NbO₃ powders with a reasonably fine particle size and single-phase perovskite structure were formed at a temperature as low as 650 °C. Dense (K_0.5Na_0.5)NbO₃ ceramics with a relative density of 93% were obtained using the refined powders. The (K_0.5Na_0.5)NbO₃ ceramics prepared by the novel hybrid method exhibited relatively good properties (d₃₃ = 90 pC/N, k_p = 0.32, P_r = 20.6 μC/cm², T_c = 405 °C, ε_r = 712), suggesting that this novel hybrid method might be a promising method for the powders and ceramics preparation.     

Thickness effect on electrical properties of Pb(Zr0.52Ti0.48)O3 thick films embedded with ZnO nanowhiskers prepared by a hybrid sol-gel route

Silicon-based lead zirconate titanate thick films embedded with zinc oxide nanowhiskers (ZnO_w-PZT) were prepared by a hybrid sol-gel route. ZnO_w-PZT films with thickness from 1.5 μm to 4 μm are perovskite structure and have smooth surface without any cracks. As the thickness increases, the remanent polarization and dielectric constant increase, but the coercive field and tetragonality decrease. Compared with PZT films, the ZnO_w-PZT film has the close tetragonality and electrical properties which are different from those of bulk PZT-based ceramic doped with ZnO powder. The thickness dependences of the ferroelectric and dielectric properties are attributed to the relaxation of internal stress.