Polymer Composite Films Research Articles

Effect of TiO2 concentration on the optical properties of polymer composite PC-PS films

The optical properties of polymer composite polycarbonate-polystyrene (PC-PS) films with different filling levels of Titanium oxide (TiO2) were studied in the visible and ultraviolent wavelength regions. It was found that the optical absorption is due to direct allowed transitions, and the energy gaps increase from 3.4863 eV for 2.5% TiO2 to 3.9034 eV for 7.5% TiO2 filler content, while the width of the tail localized states decrease with increasing TiO2 content. The optical constants refractive index n, extinction coefficient k, the realand imaginary parts of the dielectric constants have been also calculated. The dielectric constant and refractive index are also affected by TiO2 content.

Tailoring Thermal and Electrical Properties of Jeffamine Segmented Polyetherimide Composite Films Containing BaTiO3 particles.

The continuous advancement of materials science has highlighted the ongoing need for additional studies on the main composite materials topics, particularly in the field of multifunctional nano-composites, towards improving their capability to meet multifaceted requirements in order to stimulate both scientific and technological development. In this study, we report the preparation and characterization of polyetherimides (PEIs) derived from 4,4'-(4,4'-isopropylidenediphenoxy) bis (phthalic anhydride) following a two-step polycondensation reaction using either 4,4'-(1,3-phenylenedioxy) dianiline, or Jeffamine ED-600 as comonomers, or a mixture of the two diamines. Based on the PEI containing flexible Jeffamine segments, polymer composite films were developed by incorporating BaTiO3 particles. The chemical structure and morphology of the composite films were investigated by FTIR spectroscopy and scanning electron microscopy. Thermal properties were determined by thermogravimetric analysis and differential scanning calorimetry. The influence of Jeffamine segments on the thermal decomposition process was investigated by TG/MS/FTIR measurements under air and nitrogen atmospheres. Based on the obtained data, the thermal decomposition mechanism was established and is discussed in accordance with the chemical structures of the polymers. The surface properties of the PEI and PEI-composite films were characterized by performing contact angle measurements. The addition of BaTiO3 increased the wettability of the surfaces. The dielectric characteristics of polymer composite films were investigated by broad band dielectric spectroscopy measurements. It was noticed that the addition of BaTiO3 nanoparticles to the copolymer matrix gradually enhanced the dielectric constant of the composites.

A study on effect of MgO nanoparticles loading on the electrical conducting properties of polyvinyl alcohol/polyaniline polymer composite films

A study on effect of MgO nanoparticles loading on the electrical conducting properties of polyvinyl alcohol/polyaniline polymer composite films

Synthesis and Characterization of Poly(2-vinylpyridine) and Poly(4-vinylpyridine) with Metal Oxide (TiO2, ZnO) Films for the Photocatalytic Degradation of Methyl Orange and Benzoic Acid.

In this study, composite material films of pyridine-based polymer and metal oxides (ZnO and TiO2) were successfully deposited by spin coating method for environmental remediation. Firstly, the polymers poly(2-vinylpyridine) P(2-VP), and poly(4-vinylpyridine) P(4-VP) were synthesized via solution polymerization. The analysis by grazing incidence X-ray diffraction (GIXRD) reveals semicrystalline nature and scanning electron microscopy (SEM) indicates that the poly(vinylpyridines) clusters of particles were observed on the surface of the films. It was also shown that the morphology of composite materials is completely dependent on the chemical nature of the oxide. In the case of P(2-VP)-TiO2 and P(4-VP)-TiO2, some channels or pathways of TiO2 on the surface of films were observed. However, the surface morphology of the polymer composites formulated with ZnO shows a homogeneous distribution in P(2-VP) and P(4-VP) matrix. The effectiveness of the composite materials in the photodegradation of methyl orange (MO) was evaluated by photocatalysis. According to the results, the P(4-VP)-ZnO composite exhibited the highest photodegradation of MO, allowing the separation of photogenerated species required for the photocatalytic reaction. The P(4-VP)-ZnO composite was also tested in benzoic acid (BA) photodegradation in water. The presence of some scavengers in the reaction system reveals that hydroxyl radicals (OH•), superoxide radicals (O2-•) and holes (h+) are responsible for the BA reduction by photocatalysis.

Sub-40 nm nanogratings self-organized in PVP-based polymer composite film by photoexcitation and two sequent splitting under femtosecond laser irradiation

Laser-induced periodic surface structures (LIPSSs) on various materials have been extensively investigated because of their wide applications. The combination of different materials allows for greater freedom in tailoring their functions and achieving responses not possible in a homogeneous material. By utilizing a femtosecond (fs) laser to irradiate the Fe-doped Polyvinyl Pyrrolidone (PVP) composite film, highly regular ultrafine nanogratings (U-nanogratings) with a period as small as 35.0 (±2.0) nm can be self-organized on the surface with extremely high efficiency. The period of the U-nanogratings can be controlled by varying the scanning speed of the laser beam (deposited energy) and the thickness of the composite film. Based on the experimental, theoretical, and simulation results, we propose a two-step formation mechanism: composite film excitation and two sequent grating-splitting. The high photosensitivity and low glass transition temperature of the composite film facilitate the fabrication of the ultrafine nanostructures. The proposed design method for the composite material and fabrication process could not only provide a strategy for obtaining highly regular U-nanogratings, but also offer a platform to explore the interaction physics between ultra-short pulses and matter under extreme conditions.

Fabrication of binary to quaternary PVDF based flexible composite films and ultrathin sandwich structured quaternary PVDF/CB/g-C3N4/BaFe11.5Al0.5O19 composite films for efficient EMI shielding performance

This work reports the facile fabrication of binary, ternary, and quaternary polymer composite films using combinations of Polyvinylidene fluoride (PVDF), Carbon Black (CB), Graphitic carbon nitride (g-C3N4), and Aluminum doped Barium hexaferrite (BaFe11.5Al0.5O19) nanoplatelets for application as EMI shielding materials at X-band frequency. The excellent total EMI-SE of 47.39 dB in X-band for ultra-small thickness of 0.193 mm was observed for the quaternary PVDF/CB/g-C3N4/BaFe11.5Al0.5O19 composite film. The quaternary composite film was further hot pressed into sandwich-structured two-layer and three-layer composite films. The sandwich and/or multi-layered structure of the PVDF/CB/g-C3N4/BaFe11.5Al0.5O19 composite film improved the EMI shielding performance through multiple reflection loss. With the addition of intact conduction of fillers and multiple-reflection-absorption effect, the multi-layered composite structure attained the best shielding efficiency (SE) of 64.54 dB.

Development of nanosized ZnO-PVA-based polymer composite films for performance efficiency optimisation of organic solar cells

Development of nanosized ZnO-PVA-based polymer composite films for performance efficiency optimisation of organic solar cells

Insights into optical band gap identification in polymer composite films based on PVA with enhanced optical properties: Structural and optical characteristics

In this study, poly(vinyl alcohol) (PVA) was integrated with various amounts of dibismuth trioxide (Bi2O3) to produce PVA:Bi2O3 composites using casting methodology. The influence of Bi2O3 filler loading on the structure of PVA was investigated through the XRD and FTIR approaches. The XRD and FTIR outputs revealed polymer/filler interactions. For all the composite films, the transition of electrons from the filled valence band to empty conduction bands is a complicated subject in condensed matters. Band gap detection is discussed in the aspect of two models to identify the nature of electron transitions as an obscured topic in condensed matter physics. The application of Tauc's model was successful in determining the direct and indirect band gap energies. The band gap of PVA was 6.3 eV and reduced to 3.28 eV upon the insertion of 12 wt% of Bi2O3 filler. With the help of optical dielectric loss versus photon energy, the most probable exponent (γ) value in Tauc's equation was fixed. The wavelength-dependent on the real and imaginary parts of the optical dielectric function and the W-D model were utilized to determine the fundamental parameters, including N/m∗, ε∞, τ, μopt, ωp, ρopt, Ed, Eo and no. The N/m∗ is enhanced from 3.65 × 1055 m3/kg to 42.58 × 1055 m3/kg. The improvement of dispersion energy from 1.36 to 6.71 is evidence of amorphous enrichment in composite films. The W-D model uses the refractive indexes to estimate the optical band gap. The single oscillator parameter (Eo) determined from the W-D model is close enough to the band gap received from the Tauc model.

Photophysical and electronic properties of Congo red dye embedded in polyvinyl alcohol as an efficient laser optical limiter: enhancement of the electrical conductivity and dielectric properties

High-quality polymeric composite films containing Congo red dye and PVA were prepared using the casting technique. The proposed Cr-doped PVA composites were examined using XRD, UV–visible optical, dielectric, and optical limiting effect techniques. The XRD patterns of CR-doped PVA composite films display diffraction peaks belonging to CR organic dye. There was a broadening and reduction of the initial peak intensity in polymer composite films at higher doping concentrations. The band edge of CR: PVA composites reduced with a massive shift from 4.63 to 1.86 eV, where Congo red controls the energy bandgap of the PVA polymer. Dielectric permittivity diminishes with increasing the frequency and achieves constant values at higher frequencies through the relation between the electric dipole and the electric field differences. Increasing the percentage ratio of the CR doping enhances the electrical conductivity and dielectric permittivities due to the large size of the CR molecules. The solid optical limiting of the CR-doped PVA composites is determined using different laser sources of 632.8 and 532 nm wavelengths. The excellent obtained results imply that CR: PVA composite films are very significant for applying large-scale CUT-OFF laser filters for medical optical and electronic device systems.

Significantly Improved Dielectric Performance of All-Organic Parylene/Polyimide/Parylene Composite Films with Sandwich Structure.

The development of novel polymer dielectrics with enhanced dielectric performance is a great challenge for application of film capacitors in modern electronics and electrical systems. Herein, an innovative approach of chemical vapor deposition polymerization technology is proposed to prepare the all-organic sandwich structured parylene/polyimide/parylene (Py/PI/Py) composite films by employing poly(chloro-para-xylylene) (parylene C) as the outer layers and polyimide (PI) as the inner layer. The Py/PI/Py composites exhibit superior thermal resistance and outstanding mechanical properties. Moreover, thanks to the interfacial effect which contributes to reinforcing the dielectric response and the thickness effect which facilitates improving the breakdown strength, the dielectric performance of Py/PI/Py composites has been enhanced significantly. Accordingly, dielectric constant of 4.52-5.09, dissipation factor of 0.21-1.01%, and breakdown strength of 307-460MVm-1 are achieved. Besides, notable energy storage performance is also obtained in Py/PI/Py composite dielectrics. Consequently, this novel application of chemical vapor deposition polymerization method in preparing all-organic multilayered polymer composite films with sandwich structure shows promising potential in film capacitor applications in harsh conditions.

Effect of various types of clay minerals on mechanical and thermal properties of PMMA polymer composite films

Effect of various types of clay minerals on mechanical and thermal properties of PMMA polymer composite films

Vapor-Triggered Mechanical Actuation in Polymer Composite Films Based on Crystalline Organic Cages.

The fabrication of smart materials, which can efficiently mimic biological systems through the introduction of soft components, is of great importance in the emerging fields of sensors and actuators. Herein, a smart composite film that can mechanically respond to vapors trigger then readily restores its original shape upon the removal of the stimuli is reported. This actuating composite film was prepared by mixing the highly elastic poly (vinylidene fluoride) (PVDF) polymer with the flexible and crystalline organic cages (Oba-cage) at variable concentrations. The mechanism of the mechanical response could be accurately recorded due to the ordered cage crystals. This work highlights the importance of designing smart materials at the molecular level to precisely control the response or reaction upon the introduction of different triggers, which can ultimately lead to a monumental leap in the field of soft robotics.

Development of antibacterial polymer composite films from cassava starch and silver vein graphite composite

The Ceylon Journal of Science is a peer-reviewed journal published quarterly by the University of Peradeniya, Sri Lanka in March, June, September and December. It is aimed at publishing high quality research articles on topics related to different disciplines in Science. The journal accepts original research articles, book reviews, reviews and mini-reviews, short communications, opinions, research notes, and commentaries and notes. The Journal has its own website https://site.pdn.ac.lk/cjs/. The journal strictly adheres to publication ethics as emphasized by the Committee on Publication Ethics (COPE). It is indexed in Sri Lanka Journals Online (SLJOL), Directory of Open Access Journals (DOAJ), Google Scholar and Zoological Records. According to the Google Scholar;H5-Index: 12H5-Median: 15According to the Exaly (1970 – 2021);Impact Factor: 0.6 (top 19%)Extended IF: 0.6 (top 19%)H-Index: 8 (top 28%)Citations/paper: 1.42

Synthesis of a nitrogen doped reduced graphene oxide based ceramic polymer composite nanofiber film for wearable device applications

In this study, piezoelectric composite nanofiber films were fabricated by introducing nitrogen-doped-reduced-graphene-oxide as a conductive material to a P(VDF-TrFE) polymer and a BiScO3–PbTiO3 ceramic composite employing an electrospinning process. Nitrogen was doped/substituted into rGO to remove or compensate defects formed during the reduction process. Electro-spinning process was employed to extract piezoelectric composite nanofiber films under self-poling condition. Interdigital electrodes was employed to make planner type energy harvesters to collect electro-mechanical energy applied to the flexible energy harvester. From the piezoelectric composite with interdigital electrode, the effective dielectric permittivity extracted from the conformal mapping method. By introducing BS–PT ceramics and N-rGO conductors to the P(VDF-TrFE) piezoelectric composite nanofiber films, the effective dielectric permittivity was improved from 8.2 to 15.5. This improved effective dielectric constant probably come from the increased electric flux density due to the increased conductivity. Fabricated interdigital electrode using this thin composite nanofiber film was designed and tested for wearable device applications. An external mechanical force of 350 N was applied to the composite nanofiber-based energy harvester with interdigital electrodes at a rate of 0.6 Hz, the peak voltage and current were 13 V and 1.25 μA, respectively. By optimizing the device fabrication, the open-circuit voltage, stored voltage, and generated output power obtained were 12.4 V, 3.78 V, and 6.3 μW, respectively.

MgB2/NaNO2–PVA free-standing polymer composite film as a green firework: a step towards environmental sustainability

MgB2/NaNO2–PVA free-standing polymer composite film as a green firework: a step towards environmental sustainability

Poly(arylene ether nitrile)/lamellar MXene nanosheet composite films fabricated via bio-inspired dopamine surface chemistry

2D lamellar MXene nanosheets have shown the promising candidate for preparing dielectric polymer composites due to their excellent electrical and mechanical properties. However, the high dielectric loss and low temperature resistance restrict their further application, which are still big challenges. In this work, MXene nanosheets were modified by dopamine mediated chemical crosslinking with polyethylenimine, which was further incorporated into the temperature-resistant poly (arylene ether nitrile) (PEN) matrix via a simple solution-casting method to prepare the dielectric MXene/PEN composite film. Specially, the insulating layer originated from polyethylenimine and polydopamine not only enhanced the interface polarization and the uniform dispersion of MXene in the polymer matrix, but also prevented the formation of conductive network. As a result, the MXene/PEN composite film achieved the high dielectric constant of 13.3 (1 kHz) when filling content was 7 wt%, and the dielectric loss was suppressed to 0.042. As the filling content reached 5 wt%, the MXene/PEN composite film had the maximum tensile strength and tensile modulus of 70.9 MPa and 3042.6 MPa, respectively, while maintaining a high elongation at break larger than 6.5%. In addition, the composite film retained the thermal decomposition temperature (T10%) of 460–521°C and the glass transition temperature higher than 149°C. Therefore, this work provides an alternative way to prepare thermally stable and dielectric polymer composite film with high mechanical strength and low dielectric loss, which is essential to the modern electronic applications.

A new black to highly transmissive switching bilayer polymer composite films with electroactive pEA as a color buffer layer for improving electrochromic stability

AbstractTwo reported D‐A‐D monomers based on 3,4‐ethylenedioxythiophene (EDOT) were selected for electrochemical copolymerization to obtain copolymer film, named pRG. Then, a soluble polymer poly[3,4‐ethylenedioxythiophene‐alt‐3,4‐bis([2‐ethylhexyl]oxy)thiophene] (pEA) based on the EDOT derivative was screened out, which is complementary to the absorption trough of the pRG film in visible region and matched with its working potential. The bilayer composite film pRG/pEA was obtained by spinning pEA basement membrane on fluorine doped tin oxide (FTO) coated glass surface, and then in situ electrochemical polymerization of pRG film. Compared to the pRG monolayer film, the bilayer composite film shows a more saturated black color in the neutral state and significant improvement on cyclic stability (only decreased by 1.7% after 250 cycles, while pRG film decreased by 17.1%). The introduction of pEA buffer layer not only achieves the full spectral absorption of the composite film in the visible region, but also significantly improves the cyclic stability of the bilayer composite film. The assembled EC prototype device based on the pRG/pEA composite film exhibits a “black to high transmission” reversible switch. Finally, this method combining electrochemical copolymerization, spin‐coating, lamination and other methods provides a new research idea for designing and preparing black to transmissive electrochromic materials.

Study of the Effect of Modified Aluminum Oxide Nanofibers on the Properties of PLA-Based Films.

To find out whether Al2O3 nanofiller is effective in improving the characteristics of polymer composites, composite polymer films based on biodegradable polylactide and epoxidized aluminum oxide nanofibers were obtained by solution casting. Surface morphology, mechanical and thermal properties of composites were studied by SEM, IR-Fourier spectroscopy, DSC and DMA. It was shown that, below and above the percolation threshold, the properties of the films differ significantly. The inclusion of alumina nanoparticles up to 0.2% leads to a plasticizing effect, a decrease in the crystallization temperature and the melting enthalpy and an increase in the tensile stress. An increase in the content of alumina nanoparticles in films above the percolation threshold (0.5%) leads to a decrease in the crystallinity of the films, an increase in stiffness and a drop in elasticity. Finding the percolation threshold of alumina nanoparticles in PLA films makes it possible to control their properties and create materials for various applications. The results of this study may have major significance for the commercial use of aluminum oxide nanofibers and can broaden the research field of composites.

Dynamic conductivity of multilayer graphene during pulsed mechanical activation of a composite (polypropylene - graphene nanoplatelets)

Polymer composite films of polypropylene and graphene nanoplatelets were subjected to mechanical activation . Electrical current pulses are observed during this process. Fourier transforms of the signals are fitted to Havriliak-Negami model and the Kubo model for multilayer graphene. The calculated frequency dependences of conductivity are in good agreement with the experimental results. Relaxation processes and changes in the local geometry of graphene sheets under the influence of elastic waves are responsible for the effects. • Thin films of polypropylene and graphene nanoplatelets are subjected to mechanical activation. • Electrical current pulses are observed. • Fourier transforms of the signals are described by the Kubo model for multilayer graphene.

Effect of chalcone moiety on AC conductance of Metal Oxide Nano Composite doped thin polymer film

ABSTRACT PVA, Chitosan, transition metal oxide nanocomposites, and a chlorinated chalcone moiety were used to create a 0.03 cm−1 thin polymer film. Prepared films were characterized using available techniques. The prepared film shows a semi-crystalline nature, proved by XRD analysis, and the nano-scale crystalline size (40–150 nm) was also observed. The surface of the film was smooth and a blooming flower resembling structure appeared in the SEM images obtained at 5 µm. The XPS and EDX spectra reveal the presence of added transition metals and other elements present in the prepared polymer thin film. The prepared film undergoes multistage decomposition upon heating, which was proved by TGA analysis. FT-IR analysis of the film shows that there was no chemical interaction between the added compound and the host polymer; instead, physical interactions alone persisted. Higher AC conductivity was observed with a value of 1.30 × 10−6 Scm−1 at room temperature for polymer composite film made up of MONC and DCHP. This conductance varies with temperature, and at higher temperatures, both dielectric loss and dielectric constant are high. It was discovered that the presence of chalcone moiety improves the AC conductance and dielectric properties of MONC doped polymer composite film.