Pc Films Research Articles

Flexible, hierarchical MXene@SWNTs transparent conductive film with multi-source thermal response for electromagnetic interference shielding

Flexible transparent electromagnetic interference (EMI) shielding films in visual windows are crucial for the innovation of optoelectronic devices, but the challenge of balancing light transmittance and EMI shielding effectiveness (SE) still exists. Herein, this work described a flexible transparent MXene@SWNTs/PC film with a hierarchical conductive layer that was fabricated via an alternating rotation spraying method. The multi-scale hierarchical structure configured with 1D SWNTs and 2D MXene endow the obtained film with good comprehensive properties, i. e, low sheet resistance of 32.8 Ω/sq at 56.1% light transmittance, thus causing a satisfactory EMI SE of 20.8 dB. Moreover, the transparent shielding films exhibit remarkable flexibility, which can maintain steady EMI SE after 1000 continuous bending cycles. More importantly, the low sheet resistance and high light absorption capacity of hybrid conductive layer facilitate the transparent shielding film with low-voltage-driven electric heating effect and outstanding photothermal conversion ability, respectively, ensuring the normal operation under extreme cold condition. The combination of good light transmittance, satisfactory EMI shielding performance, and multi-source thermal response enables MXene@SWNTs/PC film to have great potential as a transparent shielding film in emerging optoelectronic devices.

Large-scale transfer of Ag nanowires from PET to PC film using a roll-to-roll UV lamination process for a capacitive touch sensor.

Demand for flexible transparent sensors for futuristic cars is increasing since such sensors can enhance the freedom of design and aesthetic value in the interior of cars. Herein, we propose a unique roll-to-roll UV lamination process that can expedite large-scale Ag nanowire (AgNW) transfer for a flexible capacitive sensor, using a photocurable resin composed of an epoxy acrylate oligomer, a reactive monomer (1,6-hexanediol diacrylate), and a photoinitiator (1-hydroxycyclohexyl phenyl ketone). The acryl groups in the resin were rapidly crosslinked by UV irradiation, which facilitated the AgNWs transfer from a PET to a PC substrate with the speed of 1050 cm2 min-1 and enhanced the adhesion between the AgNWs and the PC substrate. Systematic experiments were performed to determine optimal fabrication parameters with respect to the UV dose, lamination pressure, and laser dicing conditions. At the optimal fabrication conditions, the sheet resistance of AgNWs on a PC film (PC-AgNW) was as small as 36.79 Ω sq-1, which was only 3.17% deviation from that on a PET film (PET-AgNW). Furthermore, the optical transmittance of the PC-AgNW exceeded 88% over the visible range, and it was greater than that of the PET-AgNW. Notably, the sheet resistance of the PC-AgNW was almost constant after 50 taping and peeling cycles, indicating remarkable adhesion to the substrate. Furthermore, a capacitive touch sensor was fabricated using the PC-AgNW, and its switching signals were presented with and without finger touch.

Structure Design of Polymer-Based Films for Passive Daytime Radiative Cooling.

Passive daytime radiative cooling (PDRC), a cooling method that needs no additional energy, has become increasingly popular in recent years. The combination of disordered media and polymeric photonics will hopefully lead to the large-scale fabrication of high-performance PDRC devices. This work aims to study two typical PDRC structures, the randomly distributed silica particle (RDSP) structure and the porous structure, and systematically investigates the effects of structural parameters (diameter D, volume fraction fv, and thickness t) on the radiative properties of the common plastic materials. Through the assistance of the metal-reflective layer, the daytime cooling power Pnet of the RDSP structures is slightly higher than that of the porous structures. Without the metal-reflective layer, the porous PC films can still achieve good PDRC performance with Pnet of 86 W/m2. Furthermore, the effective thermal conductivity of different structures was evaluated. The single-layer porous structure with optimally designed architecture can achieve both good optical and insulating performance, and it is the structure with the most potential in PDRC applications. The results can provide guidelines for designing high-performance radiative cooling films.

Osmotic-Enhanced-Photoelectrochemical Hydrogen Production Based on Nanofluidics

Osmotic-Enhanced-Photoelectrochemical Hydrogen Production Based on Nanofluidics

Wavelength-dependent Goos-Hänchen shifts observed in one-dimensional photonic crystal films with different structures

The wavelength modulation method is innovatively adopted to measure the enhanced Goos-Hänchen (GH) shift in one-dimensional photonic crystal (1DPC) instead of typical angular modulation method. Experimental results of two samples show that dramatic effect of the photonic bandgap of different PC films on the reflection coefficient can lead to the large GH shift on several special wavelengths. The large GH shifts at different wavelengths could reveal the structure of films more clearly. The wavelength modulation method will provide a new direction for GH shift sensing and reduce the uncertainty of the calculated results in the measurement of film parameters.

Robust colloidal photonic crystal polymer films for anticounterfeiting

AbstractPhotonic crystals (PCs) with brilliant structural colors have attracted considerable attention in the field of display and anti‐counterfeiting. Here, free‐standing PC films with antistretching property and invariant brilliant structural colors during compression and deformation were prepared, by combining SiO2 PCs (nSiO2 = 1.46) into polyether sulfone (PES) matrix which has higher refractive index (nPES = 1.68). The excellent physical and chemical stability of the PC films are ascribed to the inherent robust properties of PES resin. In fact, during the stretching, compressing, friction, and bending process, the film retains its structure and optical integrity due to its stable ordered array with constant lattice spacing and effective refractive index. In addition, the appropriate index difference not only contributes to bright structural color, but also enables the PC films to have high transparency. Thus, the pattern in the film can be switched between invisible and visible state under the transformation of weak and strong light. Thereby, the film has great potential in the application of anti‐counterfeiting.

Improving mechanical and water vapor barrier properties of the parylene C film by UV-curable polyurethane acrylate coating

Abstract Parylene C (PC) films have been widely used in many fields, such as metal anti-corrosion, electronic packaging, etc. However, the relatively poor mechanical properties and the deteriorated water barrier performance due to the easy fracture under external stress have restricted their application. It is a relatively simple and good method to maintain the water vapor barrier and enhance the mechanical properties of PC film by covering a flexible coating on its surface. In this work, a new polyurethane acrylate (PUA) coating was prepared and coated on the PC film by ultraviolet curing technology to form the PC/PUA composite film. The results showed that the PUA coatings could improve the water vapor barrier and mechanical properties of the PC film simultaneously. The water vapor transmittance rate was reduced from 1.1791 g·(m−2·day−1) of the original PC film to 0.5636 g·(m−2·day−1) of the PC/PUA composite film. The elongation at break and the impact energy were increased to 48.36% and 41.67%, respectively, which would widen the application of PC films in the fields of flexible electronics or smart wear.

Nanostructuring of Mn(II)Pc thin films by vacuum deposition in a weak magnetic field

Manganese phthalocyanine, Mn(II)Pc, is a disc-like paramagnetic molecule whose unusual electronic structure have been studied for decades. However, no credible results on the direct impact of intrinsic molecular magnetism on the solid state properties of Mn(II)Pc are known. In this work, the Mn(II)Pc films were deposited by thermal vacuum evaporation with and without applying an external static magnetic field with a strength of a few tenths of a Tesla to the growth zone. Evolution of the microstructure of the thus formed films was documented using XRD, SEM, AFM and optical methods. In the field-free conditions, the Mn(II)Pc films deposited on the hot substrate are rather smooth, continuous and strongly textured. Large needle-like crystals (whiskers) grow when magnetic field is turned on, without noticeable correlation with the direction of field lines. However, the density of whiskers per unit area increases with increasing field strength. Possible explanations of the growth mechanism include molecular surface diffusion, adsorption energy lowering and Lorentz force but none of them is yet internally consistent.

Epitaxial lift-off of freestanding (011) and (111) SrRuO3 thin films using a water sacrificial layer

Two-dimensional freestanding thin films of single crystalline oxide perovskites are expected to have great potential in integration of new features to the current Si-based technology. Here, we showed the ability to create freestanding single crystalline (011)- and (111)-oriented SrRuO3 thin films using Sr3Al2O6 water-sacrificial layer. The epitaxial Sr3Al2O6(011) and Sr3Al2O6(111) layers were realized on SrTiO3(011) and SrTiO3(111), respectively. Subsequently, SrRuO3 films were epitaxially grown on these sacrificial layers. The freestanding single crystalline SrRuO3(011)pc and SrRuO3(111)pc films were successfully transferred on Si substrates, demonstrating possibilities to transfer desirable oriented oxide perovskite films on Si and arbitrary substrates.

Dielectric Hole Collector toward Boosting Charge Transfer of CsPbBr3 Hybrid Nanogenerator by Coupling Triboelectric and Photovoltaic Effects

AbstractCoupled triboelectric‐photovoltaic effect by collecting photogenerated charge carriers is increasingly important to dramatically improve the short‐circuit current output of triboelectric nanogenerators (TENG), especially for the all‐inorganic cesium lead bromide (CsPbBr3) halide perovskite combined with the optoelectronic and dielectric properties as a fundamental friction layer in TENG. Herein, hole‐extraction polydimethylsiloxane (PDMS)‐multi‐wall carbon nanotubes (MWCNTs) composite film (PC) is applied into the fabrication of vertical contact‐separation mode CsPbBr3/PC hybrid TENG with dual role of negative triboelectrification layer and photogenerated hole collector. Through precisely regulating the surface potential of PC films by tuning the MWCNT loadings, the charge quantity is greatly enhanced thanks to the triboelectric‐photovoltaic coupling effect. The best hybrid TENG at MWCNTs loading of 16 wt% achieves a transferred charge of 0.358 mC under illumination, which is nearly 30,000 times higher than that of the pristine PDMS based TENG. Impressively, the champion hybrid TENG at MWCNTs loading of 12 wt% yields a power rating density of 8.24 W m−2. This work demonstrates the PC hole collector to be a promising conductive triboelectric counterpart for efficient charge separation and extraction toward booting current density of hybrid triboelectric‐photovoltaic devices.

Ethylthio-substituted sandwich phthalocyaninato europium (III) semiconductors for sensing NO2 and NH3: Effect of the extended π-conjugate systems on tuning the conductivity and sensing behavior

By using the π-conjugated phthalocyanine macrocycle as the versatile building block, a series of five sandwich-type ethylthio substituted phthalocyaninato europium complexes, namely double-decker Eu[Pc(SC 2 H 5 ) 8 ] 2 ( Pc-1 ), triple-decker Eu 2 [Pc(SC 2 H 5 ) 8 ] 3 ( Pc-2 ), and their corresponding dimers, [Pc(SC 2 H 5 ) 8 ] 2 Eu 2 [BiPc(SC 2 H 5 ) 12 ] ( Pc-1@Pc-1 ), [Pc(SC 2 H 5 ) 8 ] 3 Eu 3 [BiPc(SC 2 H 5 ) 12 ] ( Pc-1@Pc-2 ) and [Pc(SC 2 H 5 ) 8 ] 4 Eu 4 [BiPc(SC 2 H 5 ) 12 ] ( Pc-2@Pc-2 ), are synthesized and prepared into the solution-processed films by a simple quasi-Langmuir-Shäfer (QLS) method. Combination between the extending π-conjugated system in the longitudinal and transverse directions of Pc macrocycles and/or radical nature of Pc-1 unit among different semiconducting molecules result in unusually small energy gaps (0.345–0.91 eV). Consequently, all of the semiconductors exhibit excellent conductivities. Among these materials, the conductivity for the radical species Pc-1@Pc-1 , Pc-1@Pc-2 and Pc-1 is about 3–4 times larger than that for the non-radical compounds Pc-2@Pc-2 and Pc-2 . Moreover, the QLS films of five semiconductors take excellent linear responses for both oxidizing NO 2 (100–300 ppb) and reducing NH 3 (4–8.6 ppm). Respectively, the sensitivity (in % ppm −1 ) gets increased in the order of Pc-1 < Pc-2 < Pc-1@Pc-1 < Pc-1@Pc-2 < Pc-2@Pc-2 for NO 2 , and Pc-1@Pc-2 < Pc-1 < Pc-1@Pc-1 < Pc-2@Pc-2 < Pc-2 for NH 3 . Depending on the highly extended π-conjugated systems, Pc-2@Pc-2 and Pc-2 films achieve the highest sensitivity of 208.2% ppm −1 and 0.97% ppm −1 to NO 2 and NH 3 , respectively. In addition, with a less than 2 min response time within a limit of detection at 10 ppb for NO 2 and 0.48 ppm for NH 3 , good reproducibility and selectivity have been revealed for the Pc-2@Pc-2 and Pc-2 films among the best gas sensors obtained so far for all the solution-processed films based on organic semiconductors in dry air at room temperature. More importantly, it is firstly demonstrated that the high NO 2 sensing is resulted from low Oxd 1 , and high NH 3 sensing is resulted from high Red 1 among the sandwich Pc-based semiconductors. With the highly extended π-conjugated systems of Pc, Pc-2@Pc-2 and Pc-2 films achieve the highest sensitivity to NO 2 and NH 3 . • Five sandwich phthalocyanines with extending π-conjugate systems are synthesized. • Best sensing performances are achieved to NO 2 in ppb and NH 3 in sub-ppm levels. • High NO 2 sensing is determined by low Oxd 1 , and high NH 3 sensing by high Red 1 . • Increasing in conductivity matches well with decreased trend of their energy gaps. • A new opportunity is offered for development of low-cost highly sensitive sensors.

Generation of microplastic particles during degradation of polycarbonate films in various aqueous media and their characterization

A 250-day batch experiment was conducted to examine the generation of microplastic particles from degradation of polycarbonate films in 3 aqueous media of environmental relevance. The microplastic particles generated from the experiment were characterized by SEM/EDS and micro-FTIR analysis. Hydrolysis was responsible for the cleavage of carbon-oxygen bonds in the carbonate group of polycarbonate backbone and detachment of micro-sized plastic particles from the PC film surfaces. The deionized water treatment had the highest concentration of total organic carbon and the greatest number of microplastic particles among the three treatments. Either elevated acidity or the presence of hydroxyl radical did not enhance the hydrolytic degradation of the PC films and generation of microplastic particles though hydroxyl radical caused oxidative degradation of polycarbonate by attacking the organic group but not the carbonate group. Bisphenol A was not detected in any of the treatments. The microplastic particles generated from the current experiment were highly irregular, which may have different physicochemical and toxic behaviours from the spheric synthetic ones that were frequently used in toxicity experiments.

Biocompatible polymeric pyrazolopyrimidinium cobalt(II) phthalocyanine: An efficient electroanalytical platform for the detection of l-arginine

Novel pyrazolopyrimidinium analog bearing cobalt(II) phthalocyanine polymer (poly-CoTPzPyPc), was synthesized using precursor protocol and characterized by analytical and spectroscopic techniques. The FT-IR spectra of synthesized compounds showed significant peaks corresponding to functional groups of precursors and phthalocyanine (Pc) compound. The Mass and NMR spectra confirmed the formation of target precursor compounds. The polymeric Pc film was administered on the electrode surface and applied for the detection and monitoring of l-arginine. The cyclic voltammetric studies of l-arginine at (poly-CoTPzPyPc) electrode showed a linear response between 10–100 μM range and limit of detection was found to be 2.5 μM. The diffusion coefficient (Do) for the l-arginine was calculated and found to be 1.67 × 10−6 cm2/s. In the rotating disc electrode (RDE) experiments, linear sweep voltammograms infer that the l-arginine oxidation involves 2 electrons transfer during the reaction. Chronoamperogram showed catalytic response for l-arginine in the range 2–60 μM with LoD found to be 0.6 μM. The redox-active polymeric film significantly enhanced the current response in the chronoamperometric method and displayed selective and sensitive response towards l-arginine in the existence of various other bio-molecules. The developed electrode showed good working stability and has been applied to real sample analysis which yielded satisfactory results.

Intermolecular Effects on Tunneling through Acenes in Large-Area and Single-Molecule Junctions

This paper describes the conductance of single-molecules and self-assembled monolayers comprising an oligophenyleneethynylene core, functionalized with acenes of increasing length that extend conjugation perpendicular to the path of tunneling electrons. In the Mechanically Controlled Break Junction (MCBJ) experiment, multiple conductance plateaus were identified. The high conductance plateau, which we attribute to the single molecule conformation, shows an increase of conductance as a function of acene length, in good agreement with theoretical predictions. The lower plateau is attributed to multiple molecules bridging the junctions with intermolecular interactions playing a role. In junctions comprising a self-assembled monolayer with eutectic Ga–In top-contacts (EGaIn), the pentacene derivative exhibits unusually low conductance, which we ascribe to the inability of these molecules to pack in a monolayer without introducing significant intermolecular contacts. This hypothesis is supported by the MCBJ data and theoretical calculations showing suppressed conductance through the PC films. These results highlight the role of intermolecular effects and junction geometries in the observed fluctuations of conductance values between single-molecule and ensemble junctions, and the importance of studying molecules in both platforms.

Chitosan and procyanidin composite films with high antioxidant activity and pH responsivity for cheese packaging

Chitosan–procyanidin composite films (CS–PC films) with different mass ratios were prepared by solution casting method. Their structural, thermal, physical, and antioxidant properties, antibacterial activity and pH responsivity were determined. Compared with CS–control film, CS–PC films exhibited lower solubility and higher tensile strength. The antimicrobial properties against Escherichia coli and Aspergillus niger were improved by 20.0% and 30.4%, respectively. CS–PC films indicated good antioxidant activity through their DPPH and ABTS+ scavenging rates, which were 2.45 times higher than CS–control film. pH responsivity was represented by the outstanding changes in color, which were visible to the naked eye. Food packaging film with high antioxidant activity, bacteriostatic properties and pH responsivity was prepared by CS and PC. Compared with the initial properties of cheese, the characteristics of cheese packaged with CS–PC films were obviously better than those of the control groups.

Chromophore-Free photonic multilayer films for the ultra-sensitive colorimetric detection of nerve agent mimics in the vapor phase

Recyclable, chromophore-free, one-dimensional photonic crystal (1D PC) films were used for the sub-ppm-level vapor phase colorimetric detection of diethyl chlorophosphate (DCP), a nerve agent mimic, with humidity-tunable sensitivity. 1D PC films were fabricated via the sequential alternating-layer deposition of photocrosslinkable poly(N-vinyl carbazole-co-benzophenone acrylate) [P(VC-co-BPA)] as a high-refractive-index (RI) polymer and poly(4-vinylpyridine-co-benzophenone acrylate) [P(4VP-co-BPA)] as a low RI polymer onto a black polyethylene terephthalate (PET) substrate. Distinct colorimetric detection with sub-ppm sensitivity was achieved within a few seconds when these films were exposed to DCP vapor. Furthermore, detection sensitivity and visibility increased with rise in relative humidity (RH), which indicated that detection sensitivity could be fine-tuned through the modulation of RH. This detection process was reversible and repeatable over three cycles, which indicated that these polymeric multilayer films could be recycled while maintaining excellent stability and sustainability.

A responsive photonic crystal film sensor for the ultrasensitive detection of uranyl ions.

As an effective nuclear energy resource, uranium plays an important role in industry and energy but the wastes of uranium also cause radioactive contamination, which is harmful to the environment and the human body. Herein, a responsive photonic crystal (PC) film sensor for the ultrasensitive and label-free detection of uranyl ions (UO22+) has been proposed, which is easy to construct and does not need to be combined with a hydrogel. The PC film is not pH-sensitive because it is obtained by the self-assembly of methyl methacrylate-acrylonitrile co-polymeric nanospheres (PMMA-AN). These nanospheres were modified with amidoxime groups, which have a good coordination ability with UO22+. The bindings between nanospheres and UO22+ change the refractive index and disturb the face-centered cubic structure of the film, which leads to a decrease in the diffraction peak intensity of the PC film. The sensor works in the concentration range of 10 pM to 100 μM for UO22+ determination and the decreased intensities of the diffraction peaks are linearly correlated with the logarithm of UO22+ concentration in the range from 1 nM to 100 μM. Moreover, the sensor shows good selectivity for UO22+ and can also perform the determination of UO22+ in a real sample. The responsive PC film sensor shows great potential in the label-free and ultrasensitive detection of UO22+.

Recent progress in responsive photonic crystals of block copolymers

We highlight the recent progress of BCP PC films and microparticles having tunable structural colour in response to external stimuli.

Substrate induced effects on structural, optical and electrical properties of lead (II)tetrakis (4-cumylphenoxy) phthalocyanine thin films

In the present work, thin films of Lead (II) tetrakis (4-cumylphenoxy) phthalocyanine (Pb (II) Pc) of different thicknesses ranging from 15 to 90 nm were deposited by physical vapor deposition (PVD) under a residual air pressure less than 10−6 mbar on glass and cellulose acetate polymer based transparent flexible sheets (CA), at room temperature (25 °C). The prepared films were characterized for structural, morphological and optical properties using X -ray diffraction (XRD), Atomic Force Microscopy (AFM) and UV–Vis spectroscopy techniques. The dielectric studies were performed to calculate the mobility of charge carriers and to identify the conduction mechanism in Pb (II) Pc films. The films exhibited a changeover from semi-crystalline to highly crystalline structure on changing the substrate from glass to CA. Pb (II) Pc films deposited on CA substrate exhibited enlarged porosity, larger surface area active sites for absorption and higher charge carrier mobility relative to glass substrates; which further increases with increasing film thickness.

Advantages of bulge testing and rupture mechanism of glassy polymer films

The advantages of bulge testing as a method of mechanical property analysis for polymer films was described. Deformation and rupture mechanisms of glassy polymer films during bulge testing were investigated by in situ molecular aggregation structure analyses. Heat-pressed polycarbonate (PC, weight-average molecular weight (Mw) = 38k) and poly(methyl methacrylate) (PMMA, Mw = 70k and 1.2 M (PMMA-70k and PMMA-1.2 M)) films were employed as transparent glassy polymers. Evaluations of molecular aggregation structures during bulge testing were conducted by polarized high-speed camera observation and wide-angle X-ray diffraction (WAXD) measurements. PC and PMMA-1.2 M films showed a yield point in their stress-strain curves, indicating ductility, while PMMA-70k film showed brittleness. WAXD measurements revealed that the distances between the main chains slightly increased with increasing strain. With increasing film strain above the yield point, a craze-like morphology with thinning of the film was seen for the PC film, likely due to the flexible PC molecules. Although it is difficult for PMMA molecules to orient along applied stress, a transition to the thinner state with the formation of wrinkled structures occurred for the PMMA-1.2 M film above the yield point. The transition to the thinner state, which corresponds to a discontinuous decrement of the cross-section area by deformation, might be categorized as two-dimensional crazing and/or shear deformation. PMMA-70k did not show such behavior because of the small number of entanglements. The use of a small amount of films in terms of thickness and size and the capability of observation of the entire film were given as advantages of the bulge test.