Transparent Polymer Matrix Research Articles

3D printed dosimeter incorporating leuco-crystal violet and PMMA

This paper describes the development of 3D-printed dosimeters made from radiochromic materials. Incorporating polymethyl methacrylate (PMMA) as a transparent polymer matrix and leuco-crystal violet as a radiochromic dye, these dosimeters exhibit a color change when exposed to radiation. This change provides a way to visualize and measure three-dimensional dose distributions, which is important for the accurate verification of radiation doses in radiotherapy. The use of 3D printing technology allows these dosimeters to approximate human organ geometries, which may contribute to safer and more effective radiotherapeutic applications. The dosimeters can be customized into various shapes and sizes, are lightweight, and cost-effective, making them appropriate for use in both clinical and research settings in radiotherapy. The fabrication process is detailed, and the dosimeters have been tested at doses up to 100 Gy in X-ray irradiation and analyzed for dose distribution. Bragg-peak measurements from carbon beam irradiation illustrate the dosimeters' capability to detect peak radiation doses with a spatial resolution of approximately 1 mm. These findings indicate the potential of these 3D printed dosimeters to improve the accuracy of radiation delivery, which could positively impact patient outcomes in radiotherapy.

Non-iridescent magnetite photonic crystal films and pigments with enhanced magnetic coupling effect

Non-iridescent structural color films and pigments with novel enhanced microwave absorption characteristics are successfully fabricated at room temperature for the first time. The quasi-uniform magnetite nanoparticles (CV = 0.10 ∼ 0.20) with high refractive index (n = 2.42) and broad light absorption provide evident low-angle-independent property for the structural color pigments. More importantly, a universal technical protocol is developed for preparation of photonic crystals with inorganic nanoparticles, i.e., through designing of the binding strength between nanoparticles and mediated molecules, the slurry modulus is increased to 105 Pa, which effectively drives the nanoparticles to rapidly assemble into closely packed ordered arrays by our-designed powerful assembly technique. Additionally, the structural color materials are subjected as photonic crystal pigments (∼20 wt%) embedding in a transparent polymer matrix to form color coatings. Remarkably, the photonic crystal pigments exhibit strong magnetic coupling effect and enhanced microwave absorption performance due to the regular arrangement, with superior reflection loss (RLmin) values of −14.97 dB (increase by 65.8 % compared with randomized magnetic nanoparticles), and the effective absorption bandwidth (EAB) of 2.15 GHz. This new kind of photonic crystal pigment, combining visual color and radar wave absorption, provides a novel idea for developing of multi-wave-band high-performance stealth materials.

Optimizing the transparency of nano-LiF:Cu/silicone nanocomposites for 3D optically stimulated luminescence dosimetry

Nanoparticles displaying optically stimulated luminescence embedded in a transparent polymer matrix have been proposed as a reusable high-spatial resolution 3D dosimeter. We measured the refractive indices of LiF:Cu nanoparticles and silicone and found a mismatch of 0.03-0.05 for the relevant wavelengths, explaining the transmission loss through 1 cm-sized nanocomposite dosimeters. We propose to bridge the refractive index gap by coating the LiF nanoparticles with a shell of SiO2. Initial studies show successful SiO2 growth, although more work is required to produce core-shell nanoparticles with an optimized refractive index.

Liquid Crystal Cellulose Nanocrystal/ Polyvinylpyrrolidone Pigments Engineered from Agro‐Waste Sugarcane Bagasse

AbstractBio‐inspired iridescent materials can possibly replace organic dyes and pigments, however, fabricating materials that resemble the appearance of absorbing pigments is challenging. Extracting cellulose nanocrystals (CNCs) from waste biomass is a sustainable practice in light of socio‐economic and environmental concerns. In an attempt, CNCs from sugarcane bagasse are isolated through acid hyrdolysis. Stable anisotropic dispersions of CNCs are doped with polyvinylpyrrolidone (PVP). Iridescent composite films are cast from these suspensions through evaporation–induced self‐assembly approach (EISA). The physicochemical properties of the films are studied at different loadings of PVP. These iridescent CNC/PVP composite films are then ball‐milled to produce iridescent red and blue tone color pigments. The morphology and optical properties of pigments are studied through Field emission scanning electron microscopy (FE‐SEM) and Hot‐stage Polarized Optical Microscopy (POM). These pigments are then re‐dispersed in a transparent polar polymer matrix to visually observe the color induced by them using solvent casting approach.

Robust Strategy to Improve the Compatibility between Incorporated Upconversion Nanoparticles and the Bulk Transparent Polymer Matrix.

Traditional transparent polymer nanocomposites combined with functional fluorescent inorganic nanofillers are promising for many advanced optical applications. However, the aggregation of the incorporated functional nanoparticles results in light scattering and will decrease the transparency of nanocomposites, which will restrain the application of the transparent nanocomposites. Herein, a robust synthesis strategy was proposed to modify upconversion nanoparticles (UCNPs) with polymethyl methacrylate (PMMA) to form UCNP@PMMA core@shell nanocomposites though metal-free photoinduced surface-initiated atom transfer radical polymerization (photo-SI-ATRP), and thus, the dispersity of UCNP@PMMA and the interface compatibility between the surface of UCNPs and the bulk PMMA matrix was greatly improved. The obtained PMMA nanocomposites possess high transparency and show strong upconversion photoluminescence properties, which promises great opportunities for application in 3D display and related optoelectronic fields. This strategy could also be applied to fabricate other kinds of functional transparent polymer nanocomposites with inorganic nanoparticles uniformly dispersed.

A review on the electrically conductive transparent polymer composites: Materials and applications

Polymer composites have advanced tremendously in recent decades as the outcome of notable investigations. Among these advances, electrically conductive transparent polymer composites (ECTPCs) have emerged as a potential family of materials that combine electrical conductivity with optical transparency. ECTPCs have a wide range of possible applications, including optoelectronics, solar cells, touch screens, smart windows, and more. This paper gives a complete summary of the most recent advances in the manufacture, characterization, and applications of ECTPCs. The article discussed the various conductive filler materials used in ECTPCs, including metal powder, carbon nanotubes (CNTs), and graphene alongside their incorporation methods into the transparent polymer matrix. Additionally, the factors influencing the electrical conductivity and optical transmittance of ECTPCs are thoroughly discussed, accompanied by a detailed description of characterization techniques. Despite the immense potential of ECTPCs, it is important to consider the challenges and limitations. Thus, the review addresses these concerns, including the need to strike a balance between electrical conductivity and optical transparency while ensuring long-term stability. Moreover, the future prospects for the development and practical applications of ECTPCs are explored, highlighting potential avenues for further research and advancements in this field. Overall, this review offers valuable insight into the latest advances in ECTPCs, their methods of fabrication, methods of characterization, and possible applications. By addressing challenges and outlining future directions, the current article contributes to the ongoing progress and paves the way for the practical implementation of ECTPCs in various industries.

Synergistic Effect in a Graphene Quantum Dot-Enabled Luminescent Skinlike Copolymer for Long-Term pH Detection.

The alluring properties of a luminescent graphene quantum dot (GQD)-based nanocomposite are unquestionable to realize many advanced applications, such as sweat pH sensors. The well-suited hydrophilic polymers to host GQDs can face an unavoidable swelling behavior, which deteriorates the mechanical stability, whereas the hydrophobic polymers can prevent swelling but at the same time barricade the analyte pathways to GQDs. To resolve the two aforementioned obstacles, we develop a nanocomposite film containing nitrogen-doped GQDs (NGQDs) incorporated into a transparent, elastic, and self-healable polymer matrix, composed of a hydrophobic n-butyl acrylate segment and a hydrophilic N-(hydroxymethyl)acrylamide segment for wearable healthcare pH sensors on the human body. Besides serving as the fluorescence source, NGQDs are also designed as a nano-cross-linker to promote abundant chemical and physical interactions within the nanocomposite network. This synergetic effect gives rise to a 10-fold higher mechanical strength, 7-fold increment in Young's modulus, 4-fold increment in toughness, and 15-fold more sensitivity in pH detection (pH 3-10) compared to those of the pristine copolymer and NGQDs, respectively. Moreover, the mechanically enhanced nanocomposite possesses a high self-healing efficiency (94%) at room temperature even under water and demonstrates a stable sensing performance after repetitive usage for 30 days. Our work provides insights into the simple preparation of human skinlike nanocomposite elastomers usable for wearable pH sensors.

A Polymer Blend Substrate for Skeletal Muscle Cells Alignment and Photostimulation

Substrate engineering for steering cell growth is a wide and well‐established area of research in the field of modern biotechnology. Here we introduce a micromachining technique to pattern an inert and transparent polymer matrix blended with a photoactive polymer. We demonstrate that the obtained scaffold combines the capability to align with that to photostimulate living cells. This technology can open up new and promising applications, especially where cell alignment is required to trigger specific biological functions, e.g., generate powerful and efficient muscle contractions following an external stimulus.

Improving the Lifetime of CsPbBr3 Perovskite in Water Using Self-Healing and Transparent Elastic Polymer Matrix.

This study developed a simple and efficient strategy to stabilize inorganic halide perovskite CsPbX3 at high relative humidity by embedding it into the matrix with elastic and self-healing features. The polymer matrix has a naturally hydrophobic characteristic of n-butyl acrylate segment (n-BA) and cross-linkable and healable moiety from N-(hydroxymethyl) acrylamide segment (NMA). It was chosen due to the provisions of both a surrounding protective layer for inorganic perovskite and elastic, as well as healing ability to the whole organic-inorganic composite. This fabricated CsPbBr3/PBA-co-PNMA composite was demonstrated to stably persist against the suffering from hydrolysis of perovskites when exposed to a high moisture environment. The PL intensity of the composite after crosslinking was found to be relatively stable after 30 days of exposure to air. Upon water immersion, the PL intensity of composite only showed a decrease of 32% after the first 6 h, then remained stable for 6 h afterward. Furthermore, this fabricated composite was not only flexible and relatively transparent but also exhibited excellent self-healing capability in ambient conditions (T = 25°C), in which the self-healing efficiency after 24 h was above 40%. The tensile strength and stretching ability of 5 wt% perovskite content in the random copolymer were observed to be 3.8 MPa and 553.5% respectively. Overall, flexible and self-healing properties combining with high luminescence characteristics are very promising materials for next-generation soft optical devices.

Refined RGB Strategy for the Synthesis of Polymer‐Based Full Organic Luminescent Nanotubes with Broad Emission Bands

AbstractLight‐emitting polymer nanotubes with tailored fluorescence emission bands have been prepared using organic emissive materials based on benzofuran, carbazole, and indolocarbazole scaffolds and investigated with the goal to obtain pure white‐light emission at the nanoscale. The polymer nanostructures were obtained by the anodic aluminium oxide (AAO) template method with PMMA as a transparent polymer matrix and a proficient choice of organic dyes emitting in the blue, green, yellow and red parts of the spectral range. It is demonstrated that combining aqueous dispersions of monochromatic nanotubes is an effective way of generating white light emission due to a simple correlation between the individual color components. Furthermore, it is also possible to target white emission at the nanoscale by adjusting the concentration of the dyes inside single nanotubes in order to obtain optimal color coordinates of ca. 0.3 in the CIE chromaticity diagram.

Fabrication and patterning of stretchable Ag nanowire network films embedded in an elastomeric polymer matrix

Highly transparent, stretchable electrode films were fabricated by embedding Ag nanowire (Ag NW) network in a transparent elastomeric polymer matrix. The Ag NW network was first constructed on a polymethylmethacrylate film using a wet coating process. The obtained Ag NW network was then transferred to the surface of a UV-curable elastomeric polymer film. Transmittance by the resulting film was considerable at over 80 % despite its high conductivity (60Ω/sq). Its mechanical elasticity was outstanding and reached 30 %. The surface of the film was uniform, and it was resistant to oxidation and moisture. We developed a new wet-etching process that enabled patterning with line widths below 15 μm for application to stretchable electronic devices.

Stretchable and colorless freestanding microwire arrays for transparent solar cells with flexibility

Transparent solar cells (TSCs) are emerging devices that combine the advantages of visible transparency and light-to-electricity conversion. Currently, existing TSCs are based predominantly on organics, dyes, and perovskites; however, the rigidity and color-tinted transparent nature of those devices strongly limit the utility of the resulting TSCs for real-world applications. Here, we demonstrate a flexible, color-neutral, and high-efficiency TSC based on a freestanding form of n-silicon microwires (SiMWs). Flat-tip SiMWs with controllable spacing are fabricated via deep-reactive ion etching and embedded in a freestanding transparent polymer matrix. The light transmittance can be tuned from ~10 to 55% by adjusting the spacing between the microwires. For TSCs, a heterojunction is formed with a p-type polymer in the top portion of the n-type flat-tip SiMWs. Ohmic contact with an indium-doped ZnO film occurs at the bottom, and the side surface has an Al2O3 passivation layer. Furthermore, slanted-tip SiMWs are developed by a novel solvent-assisted wet etching method to manipulate light absorption. Finite-difference time-domain simulation revealed that the reflected light from slanted-tip SiMWs helps light-matter interactions in adjacent microwires. The TSC based on the slanted-tip SiMWs demonstrates 8% efficiency at a visible transparency of 10% with flexibility. This efficiency is the highest among Si-based TSCs and comparable with that of state-of-the-art neutral-color TSCs based on organic–inorganic hybrid perovskite and organics. Moreover, unlike others, the stretchable and transparent platform in this study is promising for future TSCs.

Structural and optical properties of LSO scintillator-polymer composite films

Composite films containing homogeneously dispersed scintillation nano-particles of Lu2SiO5:Ce3+, in optically transparent polymer matrix, have been prepared and characterized through X-ray diffraction, Thermogravimetric analysis TGA, electron scanning microscopy morphology SEM and PL photoluminescence. Lu2SiO5:Ce3+ scintillator powder was successfully synthesized via Sol-Gel method. This study is realized with different mass ratios of nano-particles embedded in polystyrene and polylactic acid polymer matrix (5, 10, 15, 20%) to see the influence of nano-particles on the mechanical, structural and optical properties of films. The composites have been prepared with 200 μm thickness. It’s found that the structural proprieties change with mass ratio on each sample. PL photoluminescence show the characteristic Lu2SiO5:Ce3+ emission in the blue region and intensity varied for each film.

High power-output mechanical energy harvester based on flexible and transparent Au nanoparticle-embedded polymer matrix

The blossoming of portable electronics has raised the need to develop high power devices with multifunctionality, such as transparency and flexibility. Herein, for the first time a flexible and transparent crosslinked polyethyleneimine/poly(vinyl alcohol) composite is developed for the fabrication of mechanical energy harvester. The output of the device is markedly enhanced by the introduction of Au nanoparticles (NPs) due to the increase of the composite's dielectric property. With optimal load of AuNPs, the composite based device generates highest surface charge density manifested by maximum surface potential difference. Accordingly, an open-circuit voltage of 161.1 V, a short-circuit current density of 20 mA m−2, and a record-high peak power density of 17.73 W m−2 (16 mW) is achieved. Meanwhile, the device exhibits stability with no significant change in output after five months. Additionally, the charge transfer mechanism involved in the contact electrification process of the investigated composite is discussed. This study successfully demonstrates a promising potential of the composite in mechanical energy harvesting and an effective pathway to boost the output power through the engineering of the bulk dielectric properties.

Transparent polymer sensor for visual and photometrical detection of thiocyanate in oilfield water

A novel colorimetric sensor has been proposed for sensitive and accurate visual and spectrophotometric detection of thiocyanate using polymethacrylate matrix, which also has the potential for use with samples without pretreatment. The determination method is based on shaping of a Fe3+-thiocyanate colored complex into a transparent polymer matrix, followed by measurement of absorbance at 490 nm. The principle of this colorimetric sensor is not ordinary colorimetry, but a new colorimetric strategy that combines solid phase extraction and spectrophotometric determination of thiocyanate following completion of the color change processes. The method ensures determination of 0.8–30.0 mg L−1 of thiocyanate with the detection limit of 0.3 mg L−1. The proposed simple method makes it possible to determine visually in the concentration above 6.0 mg L−1 using a color scale. The test results show that the polymethacrylate matrix can be used for determination of thiocyanate in oilfield water.

Photoluminescence of ZnS:Cu in a Polymethyl Methacrylate Matrix

The method of agents arising directly in the (poly)methyl methacrylate medium is used to synthesize ZnS:Cu quantum dots fixed in an optically transparent polymer matrix. The optical transmittance of the polymer composites in the visible spectral region reaches 92% (at the thickness 5 mm). The photoluminescence of the (poly)methyl methacrylate/ZnS:Cu composite is defined by defects in the crystal structure of ZnS and by the system of energy levels in the band gap of ZnS. The photoluminescence signal depends on the Cu-ion concentration, the reabsorption of radiation in ZnS and (poly)methyl methacrylate, and other factors.

Фотолюминесценция ZnS : Cu в матрице полиметилметакрилата

AbstractThe method of agents arising directly in the (poly)methyl methacrylate medium is used to synthesize ZnS:Cu quantum dots fixed in an optically transparent polymer matrix. The optical transmittance of the polymer composites in the visible spectral region reaches 92% (at the thickness 5 mm). The photoluminescence of the (poly)methyl methacrylate/ZnS:Cu composite is defined by defects in the crystal structure of ZnS and by the system of energy levels in the band gap of ZnS. The photoluminescence signal depends on the Cu-ion concentration, the reabsorption of radiation in ZnS and (poly)methyl methacrylate, and other factors.

Nanodispersion in transparent polymer matrix with high melting temperature contributing to the hybridization of heat-resistant organo-modified nanodiamond

The outermost surface of a nanodiamond was modified with long-chain phosphonic acids. The thermal desorption of the modified chain was suppressed until 350 °C. Nanohybrids of the phosphonic acid-modified nanodiamonds were formed by melt-compounding them with transparent polymers with high melting points over 230 °C. The transparency of the nanohybrids containing the nanodiamonds was maintained and the size of the aggregated nanoparticles on the surface was found to be in the range of 40–70 nm. The melting temperature of the nanohybrid increased compared to that of the matrix polymer, and the D 200 crystallite size also improved. In addition, mechanical properties improved, and thermal degradation temperatures also increased; this is attributed to the good dispersion of the nanodiamonds in the polymer matrix. Furthermore, the nanohybrid exhibited the image projection ability derived from nanodiamonds with high refractive index dispersed in the matrix. Darkening due to carbonization was observed in the nanohybrid consisting of crystalline-fluorinated polymers, but it was overcome by complexing the modified nanodiamond with a fluorinated long-chain phosphonic acid. The desorbed modified chains were assumed to get incorporated into the fluoropolymer with a high molten viscosity and cause carbonization, and it seems that the miscibility of the fluorinated-modified chain resolved this issue.

Scalable Preparation of Gd2O3:Yb3+/Er3+ Upconversion Nanophosphors in a High-Gravity Rotating Packed Bed Reactor for Transparent Upconversion Luminescent Films

Optically transparent upconversion luminescent organic–inorganic nanocomposites are of great significance in many fields. The related key science problems are how to control size and uniformity of upconversion nanophosphors, as well as the dispersity of the upconversion nanophosphors in transparent polymer matrix. In this article, we reported a novel route to prepare Gd2O3:Yb3+/Er3+ nanophosphors by high gravity reactive precipitation along with post hydrothermal and calcination process. A rotating packed bed (RPB) reactor was used to create a high-gravity environment for intensified mixing during the precipitation process of particles. The as-prepared Gd2O3:Yb3+/Er3+ nanoparticles exhibited uniform particle size of <100 nm, which is much smaller than the common route (∼350 nm). After surface modification, they were also homogeneously mixed with commercial polyurethane (PU), forming flexible transparent composites. The transparent film of Gd2O3:Yb3+/Er3+-PU showed bright visible luminescence under near-in...

Photonic nanojet super-resolution in immersed ordered assembly of dielectric microspheres

Specific spatially-localized optical field structure, which is often referred to as a photonic nanojet (PNJ), is formed in the near-field scattering area of non-absorbing dielectric micron-sized particle exposed to an optical radiation. By virtue of the finite-difference time-domain technique we numerically simulate the two-dimensional array of PNJs created by an ordered single-layer microassembly of glass microspheres immersed in a transparent polymer matrix. The behavior of the main PNJ parameters (length, diameter, and intensity) is analyzed subject to the immersion depth of the microparticles and cooperative interference effects of the neighboring microspheres. We show that depending on microassembly configuration, the PNJ quality can be significantly improved; in particular, the PNJ spatial resolution better than λ/5 can be achieved.