Preparation of conducting polyaniline/TiO2 composite submicron-rods by the γ-radiolysis oxidative polymerization method

Conducting polyaniline (PAni)–titanium dioxide (TiO₂) composite micron-sized rods have been synthesized using an in situ gamma radiation-induced chemical polymerization method. Aqueous mixtures of aniline, a free-radical oxidant and/or titania nanoparticles were irradiated with γ-rays. The formation of PAni–TiO₂ composite submicron-rods is the result of free aniline cation-radicals and adsorbed aniline cation-radicals on the surface of TiO₂ nanoparticles growing together with the aid of high-energy gamma irradiation. SEM and TEM images represent the PAni–TiO₂ composite rods as having a diameter range of 0.2–0.5 μm. Electrical conductivities were checked by the standard four-point probes method and found to be 0.28 S/cm for bulk PAni and 0.15 S/cm for PAni–TiO₂ composite submicron-rods. UV–visible absorption spectroscopy showed two electronic bands at about 320 and 596 nm for bulk PAni and blue-shifted bands due to the formation of PAni–TiO₂ composites. Thermogravimetric analysis revealed that the composites have a higher degradation temperature than polyaniline alone.     

Morphology studies of doped polyaniline micro/nanocomposites containing TiO2 nanoparticles and Fe3O4 microparticles

To produce polyaniline (PAni) nanodevices that display excellent microwave absorbing behaviors, novel hexanoic acid-doped PAni micro/nanocomposites containing TiO₂ nanoparticles and Fe₃O₄ microparticles (PAni/HA/TiO₂/Fe₃O₄) were prepared by template-free method, particularly to improve the dielectric and magnetic property of PAni. PAni/HA/TiO₂/Fe₃O₄ synthesized at different polymerization temperatures and polymerization time by various TiO₂ and Fe₃O₄ contents, and particles size of TiO₂ were prepared. The aim of this research is to investigate the effect of synthesis condition on the morphology behaviors of nanorods/tubes. The resulted nanorods/tubes indicated that PAni micro/nanocomposites exhibited polymerization through elongation. PAni micro/nanocomposites synthesized at 0°C resulted in large amounts of nanorods/tubes compared with those synthesized at subzero temperature and above 0°C. PAni/HA/TiO₂ and PAni/HA/TiO₂/Fe₃O₄ synthesized using TiO₂ with diameter (particles size) 180 nm resulted in large amounts of nanorods/tubes (diameter nanorods/tubes = 80–140 nm) compared with those synthesized using TiO₂ with diameter of 30 and 6 nm. Increasing TiO₂ and Fe₃O₄ content above 10% will significantly reduce the amount of nanorods/tubes. In conclusion, synthesis parameters mentioned above are the significant factors that might affect the morphology behaviors of PAni nanostructures. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Polyaniline nanofibers for In situ MAO‐catalyzed polymerization of ethylene

In this work electro‐conductive polyaniline nanofibers (PAni‐nanofibers) were prepared via interfacial methodology. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations revealed that the synthesized PAni‐nanofibers present high aspect ratio with an average diameter of 80 nm, while they exhibit high conductivity (DC conductivity values: 4.19 ± 0.21 S cm^?1). After specific treatment to remove moisture and remaining trapped HCl from PAni‐nanofibers, it was possible to prepare promising polyethylene (PE)/PAni composites by in situ polymerization of ethylene using bis(cyclopentadienyl) zirconium(IV) dichloride (Cp₂ZrCl₂) and methylaluminoxane (MAO) as catalytic system. More precisely, various contents of PAni‐nanofibers (from 0.2 to 7 wt %) were successfully incorporated in the in situ produced PE/PAni nanocomposites. PAni‐nanofibers were found to affect significantly the crystallization of the polyolefinic matrix while preserving its thermal stability. Preliminary measurements of electric properties showed PAni‐nanofibres are able to bring electro‐conductive properties to the in situ polymerized PE/PAni composites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41197.     

A study on the synthesis,characterization and properties of polyaniline/magnesium boride nanocomposites

The present paper reports the novel synthesis of polyaniline/magnesium boride (PAni/MgB₂) nanocomposites. Nanowires 50–100 nm in diameter grown by the sol–gel technique were incorporated in the PAni to prepare PAni/MgB₂ nanocomposites, which yielded an enhancement of conductivity by 5 orders of magnitude. PAni was synthesized through the chemical oxidative polymerization method. The composition of the prepared nanocomposites was tunable, i.e. the amount of dopant was varied and the effects on various parameters were observed by different techniques. The morphology of PAni/MgB₂ nanocomposites was determined using SEM. The temperature dependence of the conductivity of all composites was measured in the temperature range 300–450 K and it was observed that samples having a high concentration of MgB₂ show the highest conductivity. The molecular structure of the nanocomposites was further characterized by Fourier Transform IR spectroscopy which showed small structural changes in the backbone of PAni. I?V measurements showed that the current increases on increasing MgB₂ content. UV?visible spectra exposed the occurrence of an indirect optical transition in the composite. © 2013 Society of Chemical Industry     

Improvement of microwave absorption for PAni/HA/TiO2/Fe3O4 nanocomposite after chemical treatment

In order to obtain efficient microwave absorbers that possess high conductivity, dielectric and magnetic properties, hexanoic acid doped polyaniline (PAni) nanocomposites which contain different ratios of ferum (II) oxide (Fe₃O₄) and titanium dioxide (TiO₂) nanoparticles were successfully prepared by in situ chemical polymerization through template free method. Chemical structure, conductivity, morphology, thermal stability, magnetic properties, and amorphous/crystalline behavior of PAni nanocomposites were characterized by Fourier transform infrared spectrometer (FTIR), four point probe, field emission scanning electron microscope (FESEM), thermal gravimetric analysis (TGA), vibrating samples magnetometer (VSM), and X‐ray diffractometer (XRD), respectively. From this study, conductivity was significantly improved from 8.48 × 10⁻⁴−1.23 × 10⁻² S/cm for PAni nanocomposites without any chemical treatment (during addition of Fe₃O₄) to 3.58 × 10⁻²−4.77 × 10⁻² S/cm for those with chemical treatment. PAni nanocomposites with chemical treatment show a narrow sharp reflection loss (RL) peak with high absorption (−48.9 dB) at lower frequency due to the limited individual Fe₃O₄ nanoparticles outside the nanorods/nanotubes as proved by the new proposed mechanism (Fig. 5 ), while it shows a broad RL peak with poor absorption (−13 dB) at higher frequency for those without chemical treatment. The novelty of this research has been focused on PAni with chemical treatment which yield better microwave absorption property (99.999% absorption), combination of high conductivity (3.58 × 10⁻²−4.77 × 10⁻² S/cm), high heterogeneity and moderate magnetization (Ms = 8.87–28.49 emu/g) compare to the PAni without chemical treatment. POLYM. COMPOS., 34:1186–1194, 2013. © 2013 Society of Plastics Engineers     

Preparation of polyaniline/TiO2 nanocomposite film with good adhesion behavior for dye‐sensitized solar cell application

In this study, novel Polyaniline (PAni)/TiO₂ nanocomposites were applied on fluoride‐doped tin oxide (FTO) glass to act as an efficient counter electrode in dye‐sensitized solar cell (DSSC) application. PAni/TiO₂ nanocomposites were synthesized via chemical oxidation process using di‐2‐ethylhexylsulfosuccinate sodium salt (NaDEHS) as dopant. The nanocomposites were characterized using fourier transform infrared and ultraviolet‐visible spectrometers. In the application of PAni as the counter electrode in the solar cell, the film showed poor adhesion on the FTO glass. Palm oil‐based alkyd was introduced into the nanocomposite mixture to improve the adhesion of the film. The findings in the work show that strong adhesion of PAni on FTO glasses has led to higher incident photon to current conversion efficiency (IPCE) in solar cell. The short circuit current (Jsc), Voc (open circuit voltage), and IPCE of the resulted PAni/TiO₂ counter electrode with good adhesion in DSSC are 15.8 mA/cm², 670 mV, and 3.0%, respectively. POLYM. COMPOS., 34:1884–1891, 2013. © 2013 Society of Plastics Engineers     

Microwave absorption property of polyaniline nanocomposites containing TiO2 and Fe3O4 nanoparticles after FeCl36H2O treatment

It is important to manipulate the synthesis parameters or additives used in order to produce conducting polymer such as polyaniline (PAni) with moderate conductivity, magnetic and dielectric properties that could enhance its microwave absorbing and shielding properties. In this communication, novel PAni/HA/TiO₂/Fe₃O₄ nanomaterials with different Fe₃O₄ contents were prepared by template‐free method by using TiO₂ and Fe₃O₄ nanoparticles as dielectric filler and magnetic filler, respectively. Before addition of ammonium peroxydisulfate (APS) for polymerization, Fe₃O₄ aqueous solution was treated with FeCl₃6H₂O in order to disperse well the Fe₃O₄ in the mixture. The result shows that better dispersion of Fe₃O₄ in the mixture by FeCl₃6H₂O treatment could significantly improve the conductivity of the nanocomposites and also activate the formation of nanorods/tubes. Moreover, PAni/HA/TiO₂/Fe₃O₄ nanocomposites treated with FeCl₃6H₂O show better microwave absorption (99.950–99.999% absorption) compared with PAni/HA/TiO₂/Fe₃O₄ micro/nanocomposites (67.0− 99.4% absorption) without treatment in frequency range of 10–13 GHz. Among the prepared PAni/HA/TiO₂/Fe₃O₄ micro/nanocomposites and nanocomposites, PAni/HA/TiO₂/Fe₃O₄ nanocomposite (treated with FeCl₃6H₂O) with 40% Fe₃O₄ exhibit the best microwave absorption (99.999% absorption at 10 GHz) because of its high conductivity, high heterogeneity and moderate magnetization. POLYM. COMPOS., 2010. © 2010 Society of Plastics Engineers     

Ferromagnetic polyaniline/TiO2 nanocomposites

Novel ferromagnetic semiconducting polyaniline PANI/TiO₂ nanocomposites were synthesized by the oxidative polymerization of aniline with ammonium peroxydisulfate in an aqueous medium, in the presence of colloidal TiO₂ nanoparticles (d ∼ 4.5 nm), without added acid. The morphological, magnetic, structural, and optical properties of the PANI/TiO₂ nanocomposites prepared at initial aniline/TiO₂ mole ratios 80, 40, and 20 were studied by scanning electron microscopy, superconducting quantum interference device, X‐ray powder diffraction, FTIR, Raman, and UV‐Vis spectroscopies. The emeraldine salt form of linear PANI chains as well as the presence of phenazine units, branched PANI chains, and anatase crystalline structure of TiO₂ in PANI/TiO₂ nanocomposites was confirmed by FTIR and Raman spectroscopies. The electrical conductivity of synthesized composites was ∼10⁻³ S cm⁻¹. The room temperature ferromagnetic response with coercive field of H_c ∼ 300 Oe and the remanent magnetization of M_r ∼ 4.35 × 10⁻⁴ emu/g was detected in all investigated PANI/TiO₂ nanocomposites. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Preparation,thermostability, and hydrophobic properties of TiO2/poly(dodecafluoroheptyl methacrylate) nanocomposites

Poly(dodecafluoroheptyl methacrylate) (PDFMA)/titanium dioxide (TiO₂) nanocomposites with high TiO₂ content were successfully prepared by emulsion polymerization process. Before polymerization, nano‐TiO₂ was pretreated by silane coupling agent. Surface groups and composition of the modified nano‐TiO₂ were characterized by Fourier transform infrared and X‐ray photoelectron spectra. The microstructure of nanocomposites was observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In addition, the thermo‐stability and wetting behavior were also investigated in relation to the dosage of TiO₂. The results showed that the thermostability is improved with the increment of TiO₂ content while hydrophilic properties exhibit nonlinear variation with the content of TiO₂. The optimal percentage of TiO₂ content in the TiO₂/PDFMA nanocomposites is 30% that could lead to the higher thermostability and hydrophobicity properties of composites. The maximum water contact angle (WCA) of nanocomposites can reach 120° ± 1°. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44377.     

Synthesis and characterization of rutile titanium dioxide/polyacrylate nanocomposites for applications in ultraviolet light‐shielding materials

Rutile titanium dioxide (TiO₂)/poly(methyl methacrylate‐acrylic acid‐butyl acrylate) nanocomposites were synthesized via seeded emulsion polymerization and characterized by Fourier transmission infrared, dynamic light scattering, X‐ray diffraction, ultraviolet–visible (UV–vis) spectroscopy, scanning electron microscopy, transmission electron microscopy, and thermogravimetric analysis to study their UV‐shielding property. The effects of the nanoseed types, surfactant concentrations, and functional monomer amounts on the polymerization conversion, particle size, emulsion stability, and morphologies of the resulting nanocomposites were investigated. The dependence of UV‐shielding performance on the nanoparticle content and dispersion was also explored. The optimized results are obtained with 2 wt% of TiO₂ nanoparticles addition, and the effectiveness of UV shielding is significantly increased by using the synthesized rutile nano‐TiO₂/polyacrylates, for which the nanocomposite coating with a thickness of 200 μm could block up to 99.99% of UV light (≤350 nm) as confirmed by UV–vis spectrometry. POLYM. COMPOS., 36:8–16, 2015. © 2014 Society of Plastics Engineers     

Fabrication of core–shell nanocomposites with enhanced photocatalytic efficacy

The current study establishes the unprecedented involvement in the evolution and production of novel core–shell nanocomposites composed of nanosized titanium dioxide and aniline‐o‐phenylenediamine copolymer. TiO₂@copoly(aniline and o‐phenylenediamine) (TiO₂@PANI‐o‐PDA) core–shell nanocomposites were chemically synthesized in a molar ratio of 5:1 of the particular monomers and several weights of nano‐TiO₂ via oxidative copolymerization. The construction of the TiO₂@PANI‐o‐PDA core–shell nanocomposites was ascertained from Fourier transform IR spectroscopy, UV–visible spectroscopy and XRD. A reasonable thermal behavior for the original copolymer and the TiO₂@PANI‐o‐PDA core–shell nanocomposites was investigated. The bare PANI‐o‐PDA copolymer was thermally less stable than the TiO₂@PANI‐o‐PDA nanocomposites. The core–shell feature of the nanocomposites was found to have core and shell sizes of 17 nm and 19–26 nm, respectively. In addition, it was found that the addition of a high ratio of TiO₂ nanoparticles increases the electrical conductivity and consequently lowers the electrical resistivity of the TiO₂@PANI‐o‐PDA core–shell nanocomposites. The hybrid photocatalysts exhibit a dramatic photocatalytic efficacy of methylene blue degradation under solar light irradiation. A plausible interpretation of the photocatalytic degradation results of methylene blue is also demonstrated. Our setup introduces a facile, inexpensive, unique and efficient technique for developing new core–shell nanomaterials with various required functionalities and colloidal stabilities. © 2018 Society of Chemical Industry     

Preparation,characterization, and properties of TiO2/PLA nanocomposites by in situ polymerization

In situ polymerization method was used to prepare TiO₂/polylactide (PLA) nanocomposites with different contents of TiO₂ in this work. The size of the organically modified TiO₂ particles was investigated by X‐ray diffraction (XRD) analysis. Scanning electron microscope (SEM) shows that nano‐TiO₂ particles disperse in the PLA evenly when the content of TiO₂ is low (less than 3 wt%). The differential scanning calorimeter (DSC), thermogravimetry analysis (TGA), and tensile test were used to study the thermal and mechanical properties of the composites. Results show that both the thermal and mechanical properties are markedly improved when the content of TiO₂ is 3 wt%. UV light irradiation and solution degradation experiment show that degradation of the composites is higher when the content of TiO₂ increases and due to the introduction of TiO₂ particles in the nanocomposites, the TiO₂/PLA nanocomposites exhibit remarkable bacteriostasic activity. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Preparation of photodegradable polypropylene/clay composites based on nanoscaled TiO2 immobilized organoclay

Photodegradable polypropylene (PP) composites were prepared via melting blending using PP and titanium dioxide (TiO₂) immobilized organically modified montmorillonite (organoclay). TiO₂ immobilized organoclay (TiO₂‐OMT) was synthesized by immobilizing anatase TiO₂ nanoparticles on organically modified clay via sol–gel method. The structure and morphology of TiO₂‐OMT were characterized by XRD and scanning electron microscope (SEM), which showed that anatase TiO₂ nanoparticles with the size range of 8–12 nm were uniformly immobilized on the surface of organoclay layers. Diffuse reflection UV–vis spectra revealed TiO₂‐OMT had similar absorbance characters to that of commercial photocatalyst, Degussa P25. The solid‐phase photocatalytic degradation of PP/TiO₂‐OMT composites was investigated by FTIR, DSC, GPC and SEM. The results indicated that TiO₂‐OMT enhanced the photodegradation rate of PP under UV irradiation. This was due to that immobilization of TiO₂ nanoparticles on organoclay effectively avoided the formation of aggregation, and thereby increased the interface between PP and TiO₂ nanoparticles. After 300 h irradiation, the average molecular weight was reduced by two orders of magnitude. This work presented a promising method for preparation of environment‐friendly polymer nanocomposites. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers.     

Polyaniline–antimony oxide composites for effective broadband EMI shielding

Conducting polyaniline (PAni)–antimony trioxide (Sb₂O₃) composites with different weight percentages (wt%) of Sb₂O₃ in PAni have been synthesized by in situ chemical oxidative polymerization. The composites were structurally and morphologically characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Measurements of electromagnetic interference (EMI) shielding, complex permittivity and microwave absorbing as well as reflecting properties of the composites were carried out in the frequency range of 8–18 GHz, encompassing the microwave X and Ku bands of practical relevance. All the computations are based on microwave scattering parameters measured by transmission line waveguide technique. It is observed that the presence of Sb₂O₃ in the PAni matrix affects the electromagnetic shielding and dielectric properties of the composites at microwave frequencies. The composites have shown better shielding effectiveness (SE) in both the X (SE in the range ?18 to ?21 dB) and Ku (?17.5 to ?20.5 dB) bands. ε′ and ε′′ values of the PAni–Sb₂O₃ composites are in the range of 64–37 and 63–30, respectively, in the frequency range of 8–18 GHz. Dielectric measurements indicated the decrease in dielectric constant with the increase in wt% of Sb₂O₃. The results obtained for the reflection and absorption coefficients indicated that PAni–Sb₂O₃ composites exhibit better electromagnetic energy absorption throughout the X and Ku bands. The results indicated that PAni–Sb₂O₃ composites can be used as potential microwave absorption and shielding materials.     

Synthesis and characterization of polypyrrole using TiO2 nanotube@poly(sodium styrene sulfonate) as dopant and template

A polypyrrole (PPy) using TiO₂ nanotube@poly(sodium styrene sulfonate) (TiO₂@PSS) as dopant and template was synthesized by chemical oxidation polymerization. The template TiO₂@PSS consisting of a TiO₂ nanotube core and PSS on the surface was prepared by a “grafting from” approach. PPy on the layer of TiO₂@PSS (TiO₂@PSS/PPy) was characterized by transmission electron microscopy, scanning electron microscopy, X‐ray photoelectron spectroscopy (XPS), Fourier‐transform infrared spectrometry (FTIR), Raman spectroscopic analysis, UV‐visible (UV‐vis) spectroscopy, thermo gravimetric analysis, and electrical conductivity analysis. Results showed that TiO₂@PSS/PPy was successfully fabricated. The electrical conductivity of the TiO₂@PSS/PPy nanocomposites at room temperature was 11.6 S cm⁻¹, which was higher than that of the PPy (4.2 S cm⁻¹). This result was consistent with those based on FTIR, UV‐vis spectroscopy, and XPS analyses. The nanocomposites have nanoparticle size and controllable morphology and thus potential applications in photoelectrochemical devices, photocatalytic devices, conductive inks, electronic printing sensors, and electrodes. POLYM. COMPOS., 37:462–467, 2016. © 2014 Society of Plastics Engineers     

Preparation and evaluation of polyaniline and polypyrrole modified water‐dispersible conducting nanocomposites of polyacrylonitrile with silica

Water‐dispersible conducting nanocomposites were prepared by precipitating polyaniline (PANI)/polypyrrole (PPY) in an aqueous suspension of polyacrylonitrile–SiO₂ (PAN–SiO₂) via K₂CrO₄–NaAsO₂ redox polymerization. Incorporation of PANI and PPY in the composites was confirmed by the FTIR spectrum. Scanning electron microscopic analyses for the PANI–(PAN–SiO₂) and PPY–(PAN–SiO₂) composites indicated formation of lumpy aggregates with irregular sizes. TEM analyses revealed formation of spherical particles with size ranging between 80 and 150 nm for PANI–(PAN–SiO₂) nanocomposite and 75–150 nm for PPY‐(PAN‐SiO₂) nanocomposites, respectively. Thermal stabilities of the PANI–(PAN–SiO₂) and PPY–(PAN–SiO₂) nanocomposites were higher than those of the individual base polymers. Conductivity values of PANI–(PAN–SiO₂) nanocomposite (10^?3 S cm^?1) and PPY–(PAN–SiO₂) nanocomposite (10^?4 S cm^?1) were remarkably improved relative to that for PAN homopolymer (>10^?11 S cm^?1). Both of these composites produced a permanently stable aqueous suspension when the polymerization was conducted in presence of nanodimensional SiO₂ as a particulate dispersant. Copyright © 2004 Society of Chemical Industry     

Characterization and physical properties investigation of conducting polypyrrole/TiO2 nanocomposites prepared through a one‐step “in situ” polymerization method

Nowadays, nanocomposites are a special class of materials having unique physical properties and wide application potential in diverse areas. The present research work describes an efficient method for synthesis of a series of polypyrrole/titanium dioxide (PPy/TiO₂) nanocomposites with different TiO₂ ratios. These nanocomposites were prepared by one‐step in situ deposition oxidative polymerization of pyrrole hydrochloride using ferric chloride (FeCl₃) as an oxidant in the presence of ultra fine grade powder of anatase TiO₂ nanoparticles cooled in an ice bath. The obtained nanocomposites were characterized by Fourier‐transform infrared (FTIR), thermogravimetric analysis (TGA), X‐ray diffraction (XRD), and scanning electron microscope (SEM) techniques. The obtained results showed that TiO₂ nanoparticles have been encapsulated by PPy with a strong effect on the morphology of PPy/TiO₂ nanocomposites. Also, the synthesized PPy/TiO₂ nanocomposites had higher thermal stability than that of pure PPy. The investigation of electrical conductivity of nanocomposites by four‐point probe instrument showed that the conductivity of nanocomposite at low TiO₂ content is much higher than of neat PPy, while with the increasing contents of TiO₂, the conductivity decreases. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of hydrothermally synthesized titanium nanotubes on the behaviour of polypropylene for antimicrobial applications

TiO₂ nanotubes (TiO₂‐Ntbs) synthesized by a hydrothermal method were used as filler to prepare polypropylene (PP) composites by melt blending. Their structural properties as well as their biocidal potential were studied. Nanotubes were used either as‐synthesized or organically modified with hexadecyltrimethoxysilane (Mod‐TiO₂). These nanoparticles form secondary structures with sizes around 100 nm that are well dispersed in the polymer matrix, but not homogeneously because agglomerates larger than 1 µm are also seen by transmission electron microscopy. Regarding the properties of the composites, the incorporation of the nanoparticles increased the polymer's crystallinity and thermal stability. The maximum decomposition temperature of the matrix increased by ca 13 °C compared to virgin PP. The nanotubes further increase the spherulite nucleation density, and therefore a reduction in the diameter of spherulites and an increase in their number were observed. Despite the above, the addition of TiO₂ nanoparticles did not modify the mechanical properties of PP. The PP/TiO₂‐Ntb nanocomposites exposed to UVA radiation showed a biocidal behaviour, reducing a colony of Escherichia coli by 81%. © 2015 Society of Chemical Industry     

A novel route for the synthesis of poly(2‐hydroxyethyl methacrylate) grafted TiO2 nanoparticles via surface thiol‐lactam initiated radical polymerization

Hybrid nanocomposites of poly(2‐hydroxyethyl methacrylate) (PHEMA) and TiO₂ nanoparticles were synthesized via surface thiol‐lactam initiated radical polymerization by following the grafting from strategy. Initially, TiO₂ nanoparticles were modified by 3‐mercaptopropyl trimethoxysilane to prepare thiol functionalized TiO₂ nanoparticles (TiO₂? SH). Subsequently, surface initiated polymerization of 2‐hydroxyethyl methacrylate was conducted by using TiO₂? SH and butyrolactam as an initiating system. The anchoring of PHEMA onto the surface of TiO₂ nanoparticles was investigated by FTIR, ¹H‐NMR, XPS, TGA, and XRD analyses. The experimental results indicated a strong interaction between PHEMA and TiO₂ nanoparticles owing to covalent bonding. The TEM and SEM images of PHEMA‐g‐TiO₂ showed that the agglomeration propensity of TiO₂ nanoparticles was significantly reduced upon the PHEMA functionalization. The molecular weight and polydispersity index of the cleaved PHEMA from the surface of TiO₂ nanocomposites were estimated by GPC analysis. An improved thermal property of the nanocomposites was observed from TGA analysis. PHEMA‐g‐TiO₂ nanocomposites were found to be highly dispersible in organic solvents. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and Characterization of Polyaniline:TiO2 Nanocomposites

Thin films of polyaniline (PANi) and PANi:titanium oxide (TiO₂) composites have been synthesized by sol—gel spin coating technique. The TiO₂ powder of particle size 50–60 nm was synthesized by sol–gel technique and the polyaniline was synthesized by chemical oxidative polymerization of aniline. The composite films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) Fourier transform infrared (FTIR) and UV-vis spectroscopy, and the results were compared with polyaniline films. The intensity of the diffraction peaks for PANi:TiO₂ composites is lower than that for TiO₂. The characteristic FTIR peaks of PANi were found to shift to a higher wave number in the PANi:TiO₂ composite. These observed effects have been attributed to the interaction of TiO₂ particles with PANi molecular chains. The room temperature resistivity of polyaniline:nano-TiO₂ composite is 3.43 × 10³ Ω cm and the resistivity of pure nano-TiO₂ particles is 1.60 × 10⁶ Ω cm.