Synthesis and Investigation of Phenol Red Dye Doped Polymer Films

The optical properties of the pure polymer film and polymer films doped with Phenol Red dye at different concentrations were investigated. The films were prepared using the casting technique. Poly (methyl-methacrylate) (PMMA) polymer was doped with the Phenol Red dye dissolved in a mixture of chloroform and little quantity of methanol, used as suitable solvent for both the dye and the polymer. The spectral absorption measurements of these films were carried out at different dye concentrations using UV-Vis double-beam spectrophotometer in the wavelength range 300 - 800 nm. The optical parameters of the prepared Phenol Red dye doped polymer films, absorption coefficient (α), extinction coefficient (κ), refractive index (n), optical and electrical conductivities (σopt and σelect), and optical energy band gap (Eg), were determined. The results showed that the Phenol Red dye doped polymer film is a good candidate for photonic applications such as, solar cells, optical sensors, and other photonic devices.

Fabrication and Characterization of Semi-Crystalline and Amorphous Dielectric Polymer Films for Energy Storage

Dielectric polymer films are energy storage materials that are used in pulse power operations, power electronics and sustainable energy applications. This paper reviews energy storage devices with focus on dielectric film capacitors. Two prominent examples of polymer dielectrics Polyetherimide (PEI) and Poly (tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride) (THV) have been discussed. Polyetherimide (PEI) is an amorphous polymer recognized for its high-temperature capability, low dielectric loss and high dielectric strength. THV is a semi-crystalline polymer with high dielectric constant, high-temperature capability and charge-discharge efficiency. The primary focus of this paper is to introduce the reader to the fabrication procedures and characterization techniques used in research labs for processing of dielectric polymers. The fabrication and characterization process of both polymers has been discussed in detail to shed the light on experimental process in this area of research.

Effect of Interfacial Adsorption on the Stability of Thin Polymer Films in a Solvent-induced Process

The stability of ultrathin polymer films plays a crucial role in their technological applications.Here,we systematically investigated the influence of interfacial adsorption in physical aging and the stability of thin polymer films in the solvent-induced process.We further identify the stability mechanism from the theory of thin film stability.Our results show that the aging temperature and film thickness can strongly influence the stability of thin PS films in acetone vapor.Physical aging can greatly improve the stability of thin polymer films when the aging temperature T_(aging1)>T_(g).A thinner PS film more quickly reaches a stable state via physical aging.At short aging time,the formation of the adsorbed layer can reduce the polar interaction;however,it slightly influences the stability of thin polymer films in the solvent-induced process.At later aging stage,the conformational rearrangement of the polymer chains induced by the interfacial effect at the aging temperature Taging1 plays an important role in stabilizing the thin polymer films.However,at T_(aging2)<T_(g),the process of physical aging slightly influences the stability of the thin polymer films.The formation of the adsorbed layer at Taging2 can reduce the short-range polar interaction of the thin film system and cannot suppress the instability of thin polymer films in the solvent-induced process.These results provide further insight into the stable mechanism of thin polymer films in the solvent-induced process.

Electric Field and Ion Diffusion Triggered Precisely Regulated Construction of Micron-scale Water-based Polymer Films:a Detailed Mechanistic Exploration

Water-based polymer films can be readily deposited onto a wide range of metallic materials as an environmentally friendly coating through the demulsification-induced fast solidification(DIFS)method.However,there is still a lack of in-depth understanding of the demulsification process of the water-based emulsions and their deposition processes.Herein,we demonstrate that the build-up process of the commercial water-based micron-scale waterborne polyurethane,polyvinyl acetate,polyurethane acrylate,and natural rubber polymer films is affected by the collective effect of electric field and ion diffusion exerted by anode-cathode electrode pairs,applied voltage,conduction time,electrode distance,and emulsion species.A structural investigation of as-prepared polymer films allows us to propose two new structure build-up models.During a flat film deposition,isolated islands are formed first and grow on the substrate surface,and eventually,their mutual coalescence forms the final layer.Whereas,for a convex layer formation,the layer is first formed in the middle of the substrate and then grows toward the sides of the convex structure of the substrate.The results presented in this work expand the understanding of the mechanism of the DIFS process and may provide some new insights into structure-oriented multifunctional material design.

An Investigation into the Role of Capping on Second Harmonic Generation from Nonlinear Organic Polymer and Guest-Host Thin Films by In-Situ Poling

In attempts to fabricate thermally stable second-order nonlinear polymer thin films, we have investigated the second harmonic generation (SHG) from both nonlinear polymer and guest-host thin films. We have also investigated the role of capping on the SHG, temporal stability and relaxation of dipole alignment. Corona poling techniques were employed to orient the dopants into the noncentrosymmetric structure required to obtain the SHG. The effect of capping with a polymeric encapsulant below the glass transition temperature of the polymers on the unpoled and corona poled thin films was studied. Capping of the nonlinear polymer and guest host thin films have resulted in high SHG with good temporal stability. SHG signal falls drastically during the first 8 days after poling while no further significant decay in SHG signal was observed after about 33 days. Our investigations have identified the characteristics required for a good encapsulant on a non-con-ductive surface.

Polymer Coatings for Protection of Wood and Wood-Based Materials

Three major types of protective coating of wood and wood-based materials have been considered. These three types include the coatings based on carboxyl-containing water-soluble polymers which are easily cross-linked by inorganic salts or OH-containing compounds, pH-sensitive coatings and polymer multi-layer structures. First of three mentioned approaches allows affecting permeability and enhancing the prevention the loss of water from the surface of wood to its surrounding. The advantage of the second approach is its ability to vary and purposely adjust the polymer composition and the number and distribution of -COOH groups in the chain which make the originally water-soluble polymers completely insoluble. The strong feature of the third approach which includes broad use of hydrogen-bonded films produced by layer-by-layer self-assembly is the possibility of manipulation of coatings stability after construction.

Layered Foam/Film Polymer Nanocomposites with Highly Efficient EMI Shielding Properties and Ultralow Reflection

Lightweight,high-efficiency and low reflection electromagnetic interference(EMI)shielding polymer composites are greatly desired for addressing the challenge of ever-increasing electromagnetic pollution.Lightweight layered foam/film PVDF nanocomposites with efficient EMI shielding effectiveness and ultralow reflection power were fabricated by physical foaming.The unique layered foam/film structure was composed of PVDF/SiCnw/MXene(Ti_(3)C_(2)Tx)composite foam as absorption layer and highly conductive PVDF/MWCNT/GnPs composite film as a reflection layer.The foam layer with numerous heterogeneous interfaces developed between the SiC nanowires(SiCnw)and 2D MXene nanosheets imparted superior EM wave attenuation capability.Furthermore,the microcellular structure effectively tuned the impedance matching and prolonged the wave propagating path by internal scattering and multiple reflections.Meanwhile,the highly conductive PVDF/MWCNT/GnPs composite(~220 S m^(−1))exhibited superior reflectivity(R)of 0.95.The tailored structure in the layered foam/film PVDF nanocomposite exhibited an EMI SE of 32.6 dB and a low reflection bandwidth of 4 GHz(R<0.1)over the Kuband(12.4-18.0 GHz)at a thickness of 1.95 mm.A peak SER of 3.1×10^(-4) dB was obtained which corresponds to only 0.0022% reflection efficiency.In consequence,this study introduces a feasible approach to develop lightweight,high-efficiency EMI shielding materials with ultralow reflection for emerging applications.

PHOTOCHROMIC PROPERTIES OF (E)-DICYCLOPROPYLMETHYLENE-(2,5-DIMETHYL-3-FURYLETHYLIDENE)-SUCCINIC ANHYDRIDE DOPED IN POLYSTYRENE THIN FILMS

Fulgide 1-E doped in polystyrene polymer films was heated at various annealing temperatures.Upon irradiation with UV light(366 nm),fulgide 1-E undergoes a conrotatory ring closure to the pink colored closed form 1-C.The later color was switched back to the original color when the films were irradiated with white light.The kinetics of photocoloration and photobleaching processes were followed spectrophotometrically by monitoring the absorbance of the ring closed product 1-C at itsλ_(max) of 525 nm.The fir...

XPS Study on Water-Soluble Polymer Surfactant Film

By means of changing the detection angle, the molecular conformation of a new type of polymer surfactant, acrylamide-poly(oxyethykene alkyl ether)acrylate-anionic monomer random copolymer, was studied by x-ray photoelectron spectroscopy(XPS) in detail.

Visible transparent,infrared stealthy polymeric films with nanocoating of ITO@MXene enable efficient passive radiative heating and solar/electric thermal conversion

Visible transparent yet low infrared-emissivity(ε)polymeric materials are highly anticipated in many applications,whereas the fabrication of which remains a formidable challenge.Herein,visible transparent,flexible,and low-εpolymeric films were fabricated by nanocoating decoration of indium tin oxide(ITO)and MXene on polyethylene terephthalate(PET)film surface through magnetron sputtering and spray coating,respectively.The obtained PET-ITO@MXene(PET-IM)film exhibits lowεof 24.7%and high visible transmittance exceeding 50%,endowing it with excellent visible transparent infrared stealthy by reducing human skin radiation temperature from 32 to 20.8°C,and remarkable zero-energy passive radiative heating capability(5.7°C).Meanwhile,the transparent low-εPET-IM film has high solar absorptivity and electrical conductivity,enabling superior solar/electric to thermal conversion performance.Notably,the three heating modes of passive radiative and active solar/electric can be integrated together to cope with complex heating scenarios.These visible transparent low-εpolymeric films are highly promising in infrared stealth,building daylighting and thermal management,and personal precision heating.

Organic Memristor Based on High Planar Cyanostilbene/Polymer Composite Films

Organic memristors with low power consumption,fast write/erasure speed,and complementary metal-oxide-semiconductor(CMOS)compatibility have attracted tremendous attention to mimic biological synapses to realize neuromorphic computation in recent years.In this paper,organic resistive switching memory(ORSM)based on(Z)-3-(naphthalen-2-yl)-2-(4-nitrophenyl)acrylonitrile(NNA)and polymer poly(N-vinylcarbazole)(PVK)composite film was prepared by spin-coating method.Device performance based on NNA:PVK composite films with different mass fractions of NNA were systematically investigated.The ORSM based on PVK:40%(mass fraction)NNA composite film exhibited non-volatile and bipolar memory properties with a switching ratio(Ion/Ioff)of 24.1,endurance of 68 times and retention time of 104 s,a“SET”voltage(Vset)of−0.55 V and a“RESET”voltage(Vreset)of 2.35 V.The resistive switching was ascribed to the filling and vacant process of the charge traps induced by NNA and the inherent traps in PVK bulk.The holes trapping and de-trapping process occurred when the device was applied with a negative or positive bias,which caused the transforming of the conductive way of charges,that is the resistive behaviors in the macroscopic.This study provides a promising platform for the fabrication of ORSM with high performance.

On Water Growth of Continuous Thin Films of Two-Dimensional Covalent Organic Frameworks with Large Single-Crystal Domains

A core feature of two-dimensional covalent organic frameworks is crystallinity, but it remains challenging to gain their thin films with high crystallinity. Here, we presented growth of thin films of two-dimensional covalent organic frameworks with an average domain size of ~2.83 μm^(2) and maximum domain size of up to ~26.19 μm^(2) using amphiphilic glycine derivatives on water surface. We envisage that this work will inspire the growth of a wide variety of organic two-dimensional materials with high crystallinity and boost their structure property investigations.

Fabrication of SAW Sensor for Detecting Chemical Agent

SAW sensors using five different types of polymer to detect of chemical agents(DMMP,CH_3CN,CH_2Cl_2,DCP) have been fabricated and its gas response characteristics were extensively investigated.The polymers used as the sensing material are polyisobutylene(PIB),polyepichlorohydrin(PECH),polydimethylsiloxane(PDMS),polyisoprene(PIP)and polybutadiene(PBD).Their thin films were coated on quartz substrate by spin coating technique.Three types of simulants gases,dimethylmethylphosphonate(DMMP),acetonitrile(CH_3CN)and dichloromethane(CH_2Cl_2),dichloropentane(DCP)were used as target gases,instead of the real nerve,blood,choking and vesicant agents.After spin coating of PIB and PECH,the substrates were heated to 65℃with N_2 flow for 1 h to remove the cyclohexane and ethylacetate which was used as solvent. PDMS was heated to 75℃with N_2 flow for 2 h to remove the ethylacetate which was used as solvent.PBD and PIP on the substrate were heated to 60℃with N_2 flow for 1 h to remove the benzen which was used as solvent.The sensing characteristics of the SAW sensors were measured by using E-5061A network analyzer.

Hot melt extrusion:An industrially feasible approach for casting orodispersible film

Over the recent few decades,many groups of formulation scientists are concentrating on rapid release dosage forms in oral cavity.Among all fast release dosage forms,orodispersible films are successful to attract pharmaceutical industry due to ease of formulation and extension patent life.Films are popular in patients too because of quick onset and user friendliness of dosage form.From the beginning,solvent casting has been selected as method of choice for manufacturing of orodispersible films.Solvent casting has been proved as a benchmark technology because of ease in product development,process optimization,process validation and technology transfer to production scale despite of some drawbacks like more number of unit operations involved and consumption of large quantity of solvents with controlled limits of organic volatile impurities in final formulation.The application of hot-melt extrusion(HME)in the pharmaceutical industry is consecutively increasing due to its proven innumerable advantages like solvent free continuous process with fewer unit operations and better content uniformity.Very few development activities has been initiated in the field of hot melt extruded orodispersible films so far.This extensive review covers detailed discussion of heavy duty industrial extruders,selection of downstream equipments,selection of excipients,common problems found in formulations and their remedies.Successive part of review addresses identification of critical quality attributes,quality target profile of product,criticality in selection of process parameters and material for substantial simulation in laboratory scale and production for successful technology transfer.

In-situ polymerized carbonate induced by Li-Ga alloy as novel artificial interphase on Li metal anode

Li metal is considered an ideal anode material because of its high theoretical capacity and low electrode potential.However,the practical usage of Li metal as an anode is severely limited because of inevitable parasitic side reactions with electrolyte and dendrites formation.At present,single-component artificial solid electrolyte interphase cannot simultaneously meet the multiple functions of promoting ion conduction,guiding lithium ion deposition,inhibiting dendrite growth,and reducing interface side reactions.Therefore,multi-component design on Li metal surface is widely investigated to achieve long-term cycling.Herein,we report a Li_(2)Ga-carbonate polymer interphase layer to solve volume changes,Li dendrites formation and side-reactions.As a result,the Li symmetric cell can be stabilized at 3.0 m A/cm^(2)in carbonate electrolyte with limited volume of 20μL.Coupled with 13.6 mg/cm^(2)(loading of 2 mAh/cm^(2))LiFePO_(4)cathode,discharge capacity retains at 90%for over 150 cycles under limited electrolyte conditions.With such an alloy-polymer interphase layer,higher energy density Li metal batteries become prominent in the near future.

Photoresponsive aggregation-induced emission polymer film for anti-counterfeiting

The development of solid-state smart materials, in particular those showing photoresponsive luminescence, is highly desirable for their cutting edge applications in displays, sensors, data-storage, and anticounterfeiting. However, to achieve both excellent photoresponsive performance and bright luminescence in solid state remains challenge. Herein, we integrate a novel photochromic fluorophore YL into flexible polymer chains, thereby enabling the resultant polymer PYL with reversible photoisomerization upon aggregation. Remarkably, the polymer PYL possesses excellent photochromic properties and aggregationinduced emission(AIE) activity, which can be attributed to the photoactive YL moiety. Upon light exposure, its film exhibits reversibly off-to-on fluorescent modulation with quick response, high emission efficiency and signal contrast, sharply different from the weak emission in solution. The novel photoresponsive AIE polymer with invisible/visible color and fluorescence transformation allows for advanced anti-counterfeiting applications. This work provides an efficient platform for constructing solid-state photocontrollable luminescent materials.

Homeotropic Alignment and Selective Adsorption of Nanoporous Polymer Film Polymerized from Hydrogen-bonded Liquid Crystal

Nano porous polymer film with a hexagonal colum nar(Coln)structure was fabricated by templated hydroge n-bonding discotic liquid crystals containing methacrylate functional group.The supramolecular hydrogen-bonded complex T3Ph-L is composed of a 1,3/5-tris(1Hbenzo[d]imidazol-2-yl)benzene(T3Ph)core molecule as the hydrogen-bonding acceptor and 3,4,5-tris((11-(methacryloyloxy)undecyl)oxy)benzoic acid(L)peripheral molecules as donors.And the Colh structure is always retained after self-assembly,photo-crosslinking,and removal of the template T3Ph.The nanoporous polymer film can retain the Colh phase even under the dry condition,which indicates more possibilities for practical applicati ons.After chemical modificati on of the inner wall of the nano pores,the nan oporous polymer film with pores of about 1 nm selectively adsorbs ionic dyes,and the adsorption process is spontaneous and exothermic in nature.Homeotropic alignment can be obtained when the blend complex was sandwiched between two modified glasses after annealing by slow cooling,which shows that the nanoporous polymer film has potential in applications such as nanofiltration.

Design of multi-passband polymer multilayer film and its application in photovoltaic agriculture

To solve the issue of the contradiction between photovoltaic power generation and plant photosynthesis for sunlight demand, we propose a design method of multi-passband polymer multilayer optical structure. Using polycarbonate(PC) and polymethyl methacrylate(PMMA), two polymer materials with different refractive indices, the passband position and passband bandwidth are calculated and adjusted by the transmission matrix method and TFCalc software. A 450 nm,660 nm, and 730 nm three-passband filter was realized by superimposing stacks of different band positions. The feasibility of the photovoltaic agriculture was confirmed by the power generation efficiency and the actual plant growth.

Mechanical behavior and wrinkling patterns of phaseseparated binary polymer blend film

The wrinkling of phase-separated binary polymer blend film was studied through combining the Monte Carlo(MC)simulation for morphologies with the lattice spring model(LSM)for mechanical properties.The information of morphology and structure obtained by use of MC simulation is input to the LSM composed of a three-dimensional network of springs,which allows us to determine the wrinkling and the mechanical properties of polymer blend film,such as strain,stress,and Young’s modulus.The simulated results show that the wrinkling of phase-separated binary polymer blend film is related not only to the structure of morphology,but also to the disparity in elastic moduli between polymers of blend.Our simulation results provide fundamental insight into the relationship between morphology,wrinkling,and mechanical properties for phase-separated polymer blend films and can yield guidelines for formulating blends with the desired mechanical behavior.The wrinkling results also reveal that the stretching of the phase-separated film can form the micro-template,which has a wide application prospect.

Characterization of electrode fouling during electrochemical oxidation of phenolic pollutant

Electrode fouling is a problem that commonly occurs during electro-oxidation water purification.This study focused on identifying the fouling behavior of Pt electrode associated with the formation of polymeric layer during electro-oxidation of phenol.The in situ electrochemical measurements and non-destructive observation of the electrode morphology were reported.The results demonstrated that the electrode fouling was highly dependent on thermodynamic process of electrode that was controlled by anode potential.At anode potential lower than 1.0 V vs SHE,the direct electro-oxidation caused the electrode fouling by the formation of polymeric film.The fouling layer decreased the electrochemically active surface area from 8.38 cm^(2)to 1.57 cm^(2),indicated by the formation of polymeric film with thickness of 2.3µm,increase in mass growing at a rate of 3.26µg/cm^(2)/min.The degree to which the anode was fouled was independent of anion in the electrolyte.In comparison,at anode potential higher than 2.7 V vs SHE,the anions(e.g.,chloride)could exert a major influence to the behavior of electrode fouling.The presence of chloride was shown to mitigate the fouling of electrode significantly through preventing the formation of polymeric film by active chlorine(e.g.,Cl•and Cl_(2))produced from anodic oxidation of chloride.Since chloride is the most abundant anionic species existing in both natural and engineered water system,this study not only offers a deep insight into the mechanism of electrode fouling,but also suggests strategies for anti-fouling in the presence of chloride in electro-oxidation process.