In order to shield the electronic circuits on a transparent polyimide (PI) substrate, an anti-reflection (AR) layer was deposited on a PI film via DC reactive magnetron sputtering. The effects of sputtering power and thickness of AR layer on the optical property and adhesion strength of the PI were investigated. The composition of the AR layer influences the bonding between layers. Sufficient thickness of the AR layer is essential to strengthen the adhesion between the PI and copper (Cu) layers. The sputtered AR layer on the PI also improves the barrier property for water vapor. The AR layer-sputtered PI substrates remain transparent and exhibit high peel strength to the Cu layer, suggesting their potential applications as reliable transparent substrates for modern electronic devices.

Heterogeneous catalysts based on metallic nanoparticles are promising candidates for wastewater treatment. However, they aggregate easily as a result of their high surface energy. Polymers are very popular supporting catalyst materials because they can stabilize the metallic nanoparticles to prevent aggregation. In this study, aniline-pentamer-based electroactive polyurea (EPU) was synthesized by oxidative coupling, and Au nanoparticles were anchored to the EPU via its aniline segments. Electrochemical redox behavior of the as-synthesized EPU was monitored by electrochemical cyclic voltammetry. The Au/EPU composite was characterized by FTIR, UV–vis, TGA, SEM, TEM, XRD XPS, and ICP-OES. SEM showed that the EPU had a flower-like structure, and the Au nanoparticles were uniformly immobilized on the EPU surface. The reduction of 4-nitrophenol (4-NP) by NaBH4 was used as a model reaction to evaluate the catalytic properties of the Au/EPU composite. Moreover, the optimization of the reaction conditions for the reduction of 4-NP to 4-aminophenol (4-AP) were also studied in detail. The Au/EPU composite catalyzed the reduction of 4-NP to 4-AP within 4 min with a rate constant of 2.4 × 10–2 s−1 and an activation energy of 40.17 kJ/mol. The Au/EPU composite demonstrated high conversion (98%) after 20 successive cycles.

This article presents the first successful application of an Au/electroactive polyamide (EPA) composite as a catalyst for the reduction of nitrophenol (NP) to aminophenol (AP). The EPA was synthesized by an oxidative coupling reaction, and the in situ chemical oxidation of the reduced form of the soluble EPA in N-methyl-2-pyrrolidone was monitored by UV–vis spectroscopy. Moreover, the electroactivity of the EPA was evaluated by electrochemical cyclic voltammetry studies. The amino functional groups of the EPA were used to anchor Au nanoparticles to form an Au/EPA composite. Characterization of the Au/EPA composite was performed by field-emission scanning electron microscopy, field-emission transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The Au/EPA composite showed an excellent performance for the reduction of NP to AP, and a conversion higher than 95% was achieved after 180 days or 30 cycles of reuse.

Flexible and thermally stable polyimide (PI) films containing a hierarchical surface structure were synthesized as substrates to support visible-light active cuprous oxide for photocatalytic reduction of carbon dioxide for the first time. With the nanocasting technique, the surface structure on the leaves of Xanthosoma sagittifolium was successfully duplicated on PI films. Followed by the ion-exchange process and adequate thermal treatment, cuprous oxide nanoparticles were successfully immobilized on the artificial PI leaves and exhibited the capability to photoreduce carbon dioxide into carbon monoxide under visible-light illumination. With the selection of biomimetic structures and adjustment of fabrication parameters, the hydrophobicity and optical absorption edge of the photocatalytic film were tunable. An increase in hydrophobicity improved the yield of carbon monoxide. The introduction of a hierarchical structure on the surface and cuprous oxide within the matrix dramatically enhanced the thermal stability of the PI film. The flexible photocatalytic film is a promising material for the applications requiring high mechanical and thermal stability, such as industrial flue-gas treatments.

Two types of synthesized graphene oxide (GO) were electrophoresed using various reductants and temperature controls on the Au electrode of a quartz crystal microbalance (QCM) device for humidity detection. Characteristics of the synthesized GO, its surface morphology, and its functional groups were investigated by SEM images based on EDS and Fourier transform infrared spectra (FTIR). Structure and lattice were clear resolved using 80 kV field emission gun TEM (FEG-TEM) and electron diffraction (SAED), respectively. The resonant frequency and impedance were complementary utility to illustrate the sensitivity of various GO loaded QCM sensors. The kinetic parameters of the adsorption-desorption at a related humidity of 23-95% were extracted using the Langmuir isotherm model. In this experiment, the GO(TC) synthesized by a strong reductant NaNO3 and temperature control was demonstrated to exhibit excellent humidity sensing sensitivity with a fast absorption-desorption rate, making it a potential candidate for moisture detection.

A simple method was developed to fabricate magnetically and optically responsive actuators utilizing composites of polycaprolactone (PCL) and polydimethylsiloxane (PDMS) loaded with iron oxide (Fe3O4) nanoparticles. An electrospinning technique enables to obtain Fe3O4 / PCL/PDMS composites with nanofiber structure. We demonstrate the self-folding ability of our developed composites upon exposing to external alternating magnetic field (AMF) or light. The self-folding behavior contributed to the structure change and stress relaxation of the composites, resulting from the temperature increase caused by the AMF and light absorption properties of Fe3O4 nanoparticles. The findings in this work could provide new ideas to design advanced complex self-folding materials.

Titanium dioxide- carbon nanotube (TiO2-CNT) composites are promising for application of photocatalysis. Therefore, the aim of this study is to develop a TiO2-CNTcomposite with reversible superhydrophobicity and superhydrophilicity for use in self-cleaning application. The amount of TiO2 precursor, the added water, and the reaction time were systematically studied to obtain a TiO2 layer with desired thickness coated on the surface of CNT. In addition, the heat-treatment was utilized to control the crystalline structure of TiO2 and the hydrophobicity and hydrophilicity of resulting TiO2-CNT composites. The photocatalytic activity of the developed composites was evaluated by the photodegradation of a methylene blue (MB) solution under the illumination of ultraviolet (UV) light at ambient temperature. Experimental results demonstrated that a layer of anatase TiO2 with thickness of 21nm, 27nm, or 65nm was successfully coated on the surface of CNT. The resulting TiO2-CNT composites are superhydrophobic, which the water contact angles ranged from 143o to126o based on the thickness of TiO2 layers. After subjected to a UV light, they became hydrophilic with a water contact angle less than 50o . Furthermore, the water contact angle of these TiO2-CNT composites restored to their original values without UV exposure, confirming they were with reversible superhydrophobicity and superhydrophilicity. Moreover, the developed TiO2-CNT composites also exhibited the capability of photocatalytic degradation of methylene blue (MB).

The electrocatalytic oxidation of vitamin C at carbon paste electrode (CPE) modified with amino-functionalized multiwalled carbon nanotube/electroactive polyurea (AF-MWCNT/EPU) composite was investigated. We have synthe- sized novel electroactive polyurea composites containing MWCNTs functionalized with 4-aminobenzoyl groups by an oxidative coupling polymerization. Ultraviolet-Visible spectra and cyclic voltammetry studies confirmed the occurrence of efficient interaction between AF-MWCNT and EPU graft. Moreover, the electrocatalytic activity of vitamin C oxidation by utilizing aniline containing composites was evaluated, showing that the intrinsic electroactivity of AF-MWCNT/EPU-CPE had great potential application for detection of vitamin C. The detection limit and sensitivity of this sensor was 1.2 µM and 35.3 !A·mM -1 , respectively.

SConstruction electroactive polyamide (EPA) with aniline-pentamer-based in the main chain has been modified on the surface of carbon paste electrode (CPE) for detecting ascorbic acid (AA). Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy studies confirm the well-defined molecular structure of the oligoaniline and EPA. Further, the in situ chemical oxidation of EPA was monitored by UV-Visible absorption spectrum. The electroactivity of the EPA was evaluated by performing electrochemical cyclic voltammetry study. The sensing response studies have revealed that this EPA-modified CPE electrode can detect AA in the range of 0.05-0.7 mM with detection limit of 0.005 mM and sensitivity of 1.5 x 10(-5) AmM-1. Besides, this EPA-modified CPE electrode shows a minimal relative standard deviation of 1.73%.

Polymeric composite materials hold promise for versatile advanced applications. Of utmost importance for these applications is incorporating inorganic particles within polymer matrices which lead to multifunctional polymeric composites with desired functions. Specifically, thermosensitive polymeric hydrogels incorporating particle fillers have elicited widespread interest because of promising applications in drug delivery, tissue engineering, and medical devices. Although these materials are frequently discussed in many research fields, there are no decisive conclusions reported in literature, showing how the particle filler affects the rheological and mechanical behaviors of the resulting hydrogels. In this research, hydroxyapatite (HAp) bioceramics with definable morphologies were synthesized in order to reveal their effects on the resulting properties of HAp/polymer composite hydrogels. HAp particles with spherical, sheet-like and rod-like shapes were prepared with assistance by adding amphiphilic surfactant, poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) in synthesis. Thermosensitive composite hydrogels with controllable rheological and mechanical properties were thus developed by incorporating HAp particles into poly(ethylene glycol)-b-poly(lactide-co-glycolide)(PEG-PLGA) hydrogel. Experimental results revealed that the rheological and mechanical properties of the resultant HAp/PEG-PLGA composite hydrogel not only influenced by the added HAp particle amount, but also by the particle morphology and interactions between particles and hydrogels. The findings from this research provide a critical guideline for designing thermosensitive composite hydrogels with required rheological and mechanical properties.

ABSTRACT A novel superhydrophobicelectroactive fluorinated polyimide (HEFPI) was first synthesized from aniline trimer and 4,4′-(Hexafluoroisopropylidene) diphthalic anhydride. The HEFPI could be fabricated as superhydrophobicfilm by replicated the surface of the Xanthosomasagittifolium leaves. The water contact angle of HEFPI film reaches as high as 157 ° and the superhydrophobic property of HEFPI could coat on cold-rolled steel (CRS) to prevent the metal corrosion. Electroactivity of EFPI was evaluated by performing electrochemical cyclic voltammetry study. Besides, redox catalytic capabilities of aniline trimer units existed in HEFPI main chain may induce the formation of passive metal oxide layers on the CRS electrode. The synergistic effects (hydrophobic property and passive metal oxide layers) make the HEFPI coating has great potential for advanced anticorrosion material.

Electrospun magnetic iron/polyaniline nanofibers with applicable heating performance in an. AC magnetic field were developed. A new and low-cost method was introduced to synthesize metallic iron (Fe-0) nanoparticles with uniform size distribution. The Fe-0 nanoparticles were synthesized in an aqueous environment at room temperature with the assistance of polyvinylpyrrolidone and sodium citrate to tailor their particle sizes ranging from 10 to 20 nm. The experimental results showed. that regulating the. free iron ions present in the. solution is critical for obtaining Fe-0 nanoparticles with narrow size distribution. The Fe-0 nanoparticles were subsequently incorporated with conductive polyaniline (PANI) to fabricate Fe-0/PANI/ polycaprolactone nanofibers using an. electrospinning technique. The resultant composite nanofibers have controlled fiber diameters and also show electrochemical redox properties originating from the PANI polymer. The heating performance test concluded that both. eddy current loss from PANI and. Neel relaxation loss of magnetic Fe-0 nanoparticles can contribute to the. power dissipation of the prepared composite nanofibers. The optimal heating performance can be obtained by adjusting the composition of Fe-0 nanoparticles and PANI in nanofibers.

This article investigates the electrochromic properties and electrochemical biosensing application of electroactive polyazomethine (EPA). The novel EPA, with aniline-pentamer-based in the main chain, was synthesized from oligoazomethine and p-phenylenediamine by oxidative coupling polymerization. The well-defined molecular structure of the oligoaniline and EPA was confirmed by LC-Mass, 1H nuclear magnetic resonance (NMR), 13C NMR, and Fourier-transform infrared (FTIR) spectroscopy. Moreover, the electroactivity of the EPA was evaluated by performing electrochemical cyclic voltammetry studies. The prepared EPA was found to exhibit redox properties that could be used as electrochromic material and ascorbic acid (vitamin C, AA) sensor. The color transition of EPA thin film was found to change from light gray to green via oxidation by adjusting the voltage. A linear relationship between the concentration of AA added and the change of peak current obtained, as shown by the linear calibration curve of the amperometric response of the carbon paste electrode (CPE) modified with EPA sensor to the concentration of AA (R2=0.995, n=10). The limit of detection for the EPA-CPE was estimated to be 7.1μM at a signal to noise ratio of 3.

A simple method to obtain high magnetic permeability (mu(r)), high dielectric permittivity (epsilon(r)), and low loss polymer composites with core/shell iron/metal oxide particles is developed. Magnetic iron (Fe-0) particles with protective SiO2 shells are synthesized in aqueous environment at room temperature. The shells provide electrical insulting layers which decrease energy loss and also prevent the possibility of mu(r) decrease due to Fe-0 oxidation. Furthermore, Fe-0 particles could also be coated with TiO2 shells which allow epsilon(r) to be tuned. The epsilon(r) and mu(r) of the resulting polydimethylsiloxane composites are optimized for core-shell particle doping. The value of epsilon(r) is up to 9.8 and most importantly, the mu is close to 2 at 1 GHz with 43 wt% doping of core-shell particles. The dielectric loss of the composites is less than 0.02.

Thermoelectric materials are very effective in converting waste heat sources into useful electricity. Researchers are continuing to develop new polymeric thermoelectric materials. The segregated-network carbon nanotube (CNT)-polymer composites are most promising. Thus, the goal of this study is to develop novel porous CNT -polymer composites with improved thermoelectric properties. The research efforts focused on modifying the surface of the CNT with magnetic nanoparticles so that heat was released when subjecting to an AC magnetic field. Subsequently, polymers covered on the surface of the CNT were crosslinked. The porous CNT -polymer composites can be obtained by removing the un-crosslinked polymers. Polydimethylsiloxane polymer was utilized to investigate the effect of porosity and electrical conductivity on the thermoelectric properties of the composites. This AC magnetic field-assisted method to develop porous carbon nanotube/polymer composites for application in thermoelectric materials is introduced for the first time. The advantage of this method is that the electrical conductivity of the composites was high since we can easily to manipulate the CNT to form a conducting path. Another advantage is that the high porosity significantly reduced the thermal conductivity of the composites. These two advantages enable us to realize the polymer composites for thermoelectric applications. We are confident that this research will open a new avenue for developing polymer thermoelectric materials.

The electrochemical oxidation of ascorbic acid (vitamin C, AA) on the surface of carbon paste electrode (CPE) modified with electroactive polyurea (EPU) was studied by using cyclic voltammetry. EPU, with aniline-pentamer-based in the main chain, was synthesized from oligoaniline and p-phenylenediamine by oxidative coupling polymerization. The well-defined molecular structure of the oligoaniline was confirmed by LC-Mass, 1H NMR and FTIR spectroscopy. The in situ chemical oxidation of the reduced form of soluble, EPU in N-methyl-2-pyrrolidone was monitored by UV–visible absorption spectra. Moreover, the electroactivity of the EPU was evaluated by performing electrochemical cyclic voltammetry studies. A linear relationship between the concentration of AA added and the change of peak current obtained, as shown by the linear calibration curve of the amperometric response of the CPE modified with EPU sensor to the concentration of AA (R2=0.996, n=10). The limit of detection for the EPU-CPE was estimated 6.1μM at signal/noise of 3.

In this study, a series of electroactive polyimide/SiO2 (EPIS) composite materials containing conjugated segments of electroactive amino‐capped aniline trimer (AT) unit were successfully prepared. First of all, the amino‐modified silica (AMS) particles of ∼100 nm in diameter were synthesized by performing the conventional base‐catalyzed sol–gel reactions. Subsequently, the AMS nanoparticles were blending into the polymerization reactions between AT and 4,4′‐(4,4′‐isopropylidenediphenoxy)‐bis(phthalic anhydride), leading to the formation of EPIS composites. The as‐prepared EPIS materials in the form of coating on cold‐rolled steel (CRS) electrode were found to be much superior in corrosion protection over those of non‐electroactive polyimide and EPI materials based on a series of electrochemical corrosion measurements in saline. The significant enhancement in corrosion protection of EPIS coatings on CRS electrodes might probably be attributed to the redox catalytic property of organic EPI inducing the formation of passive metal oxide layer and the barrier property of well‐dispersed AMS nanoparticles existed in EPI matrix. POLYM. COMPOS., 35:617–625, 2014. © 2013 Society of Plastics Engineers

The concept of texturing steel surfaces were attempted to ease the surface wear and to prevent the release of harmful ions in the conventional joint replacement systems. The surfaces of the bio-compatible steels were textured by photolithography and electrochemical etching techniques to lower the friction coefficient and hence reduce the wear of the surface. Experimental results confirmed that the surfaces with textures (grooves) showed lower friction coefficient compared to un-textured surfaces at a high load (50 N). The friction coefficient could be further reduced for a lower load (10 N) through optimizing the generated hydrodynamic lift. A significant 47% reduction of friction coefficient was archived by tailoring the orientation and size of the textures on the stainless steel surface. The demonstrated strategy in this study would thus offer exciting avenues for developing artificial joint systems that last the full duration of the patients' life without any side-effect concerns.