- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
A simple layer-stacking technique to generate biomolecular and mechanical gradients in photocrosslinkable hydrogels
摘要： Physicochemical and biological gradients are desirable features for hydrogels to enhance their relevance to biological environments for three-dimensional (3D) cell culture. Therefore, simple and efficient techniques to generate chemical, physical and biological gradients within hydrogels are highly desirable. This work demonstrates a technique to generate biomolecular and mechanical gradients in photocrosslinkable hydrogels by stacking and crosslinking prehydrogel solution in a layer by layer manner. Partial crosslinking of the hydrogel allows mixing of prehydrogel solution with the previous hydrogel layer, which makes a smooth gradient profile, rather than discrete layers. This technique enables the generation of concentration gradients of bovine serum albumin in both gelatin methacryloyl (GelMA) and poly(ethylene glycol) diacrylate hydrogels, as well as mechanical gradients across a hydrogel containing varying gel concentrations. Fluorescence microscopy, mechanical testing, and scanning electron microscopy show that the gradient profiles can be controlled by changing both the volume and concentration of each layer as well as intensity of UV exposure. GelMA hydrogel gradients with different Young’s moduli were successfully used to culture human fibroblasts. The fibroblasts migrated along the gradient axis and showed different morphologies. In general, the proposed technique provides a rapid and simple approach to design and fabricate 3D hydrogel gradients for in vitro biological studies and potentially for in vivo tissue engineering applications.
关键词： 3D cell culture,Gelatin methacryloyl,Photocrosslinkable hydrogel,Poly(ethylene glycol) diacrylate,Gradient
更新于2025-11-21 11:24:58
-
Transparent Platinum Counter Electrode Prepared by Polyol Reduction for Bifacial, Dye-Sensitized Solar Cells
摘要： Pt catalytic nanoparticles on F-doped SnO2/glass substrates were prepared by polyol reduction below 200 °C. The polyol reduction resulted in better transparency of the counter electrode and high power-conversion efficiency (PCE) of the resultant dye-sensitized solar cells (DSSCs) compared to conventional thermal reduction. The PCEs of the DSSCs with 5 μm-thick TiO2 photoanodes were 6.55% and 5.01% under front and back illumination conditions, respectively. The back/front efficiency ratio is very promising for efficient bifacial DSSCs.
关键词： dye-sensitized solar cell,platinum,bifacial,ethylene glycol,counter electrode
更新于2025-11-21 11:01:37
-
Development of Graphitic Domains in Carbon Foams for High Efficient Electro/Photo-to-Thermal Energy Conversion Phase Change Composites
摘要： In this research work, hierarchical porous carbon foams (CFs) with high surface area and three dimensionally (3D) interconnected macro/meso/microporous structures were prepared through pyrolysis of stabilized poly(acrylonitrile-co-divinylbenzene) P(AN-co-DVB) polyHIPE foams at 900 °C under nitrogen atmosphere. The prepared CFs revealed high surface area (540 m2 g-1), semi-ordered nanoporosity, high electrical conductivity (470 S m-1) and high graphitization degree. Further, HR-TEM observation of CFs revealed the formation of graphitic domains in the structures. The obtained CFs were employed for encapsulation of phase change materials (PCMs) e.g. paraffin (PA) and polyethylene glycol (PEG). The prepared PCMs composites revealed the excellent reversible thermal/chemical stability after frequent 200 heating/cooling cycles. Black CF/PA and CF/PEG composites can be promising structures to driven either by applying a small voltage (3-3.6 V) with high electric-to thermal efficiency (up to 85%) or by irradiating with sunlight with high photo-to thermal efficiency (up to around 91%).
关键词： paraffin and poly ethylene glycol,carbon foam,phase change materials
更新于2025-09-23 15:23:52
-
Highly Responsive PEG/Gold Nanoparticle Thin Film Humidity Sensor via Inkjet Printing Technology
摘要： In this study, a highly responsive humidity sensor is developed by printing gold nanoparticles (GNP) grafted with a hygroscopic polymer. These GNPs are inkjet printed to form a uniform thin film over an interdigitated electrode with controllable thickness by adjusting the printing parameters. The resistance of the printed GNP thin film decreases significantly upon exposure to water vapor and exhibits a semi-log relationship with relative humidity (RH). The sensor can detect RH variations from 1.8% to 95% with large resistance changes up to 4 order of magnitude with no hysteresis and small temperature dependence. In addition, with a thin thickness, the sensor can reach absorption equilibrium quickly with response and recovery times of ≤1.2 and ≤3 seconds, respectively. The fast response to humidity changes also allows the GNP thin film sensor to distinguish signals from intermittent humidification/dehumidification cycles with a frequency up to 2.5 Hz. The printed sensors on flexible substrates show little sensitivity to bending deformation and can be embedded in a mask for human respiratory detection. In summary, this study demonstrates the feasibility of applying printing technology for the fabrication of thin film humidity sensors, and the developed methodology can be further applied to fabricate many other types of nanoparticle based sensor devices.
关键词： inkjet printing,respiratory monitoring,Humidity sensor,gold nanoparticle,poly(ethylene glycol)
更新于2025-09-23 15:23:52
-
Influence of silicon dioxide medium on the structural and electrical properties of nickel zinc ferrite
摘要： Nickel zinc ferrite [(Ni 0:65 Zn 0:35 Fe 2 O 4)x / (SiO 2)1(cid:0)x where, x = 1.0, 0.85, 0.65, 0.50, 0.35, and 0.15] is synthesized using the glyoxylate precursor method. The synthesis, characterization, and electrical study of nickel zinc ferrites/SiO 2 powder with low dielectric constant, very low conductivity, and loss tangent with low frequency dispersion, suitable for good insulators, is reported here. X-ray diffraction, TGA, and FT-IR studies are employed for identifying crystalline phases and structure. Crystallite size is calculated by the Scherrer formula and Williamson–Hall equation and found to fall in the range of 4.9–25 nm. TEM of the samples shows spherical particles of uniform size distribution and the spotty rings of SAED patterns are analyzed for identifying the crystal planes. The study confirms a simple and efficient way to synthesize single-phase nickel zinc ferrite (NZFO) spherical particles of nano size ( (cid:25) 15 nm at 1000 ? C) with lower particle agglomeration in comparison to any other methods. Electrical studies are carried out using an LCR meter. The observed value of dielectric constant falls in the range of 10–80, loss tangent in the range of 0.05–0.4, and electrical conductivity in the range of 10 (cid:0)4 to 10 (cid:0)7 mho m (cid:0)1 . These values are respectively functions of temperature, frequency, and the ferrite content in ferrite/SiO 2 samples. A proper selection of ferrite concentration in the silica medium enables one to prepare NZFO/SiO 2 material of very low loss tangent with dielectric constant in the range of 10–80.
关键词： tetraethyl orthosilicate,dielectric constant,Nickel zinc ferrite,dielectric conductivity,loss tangent,ethylene glycol
更新于2025-09-23 15:21:21
-
Novel lanthanidomesogens based on poly(ethylene glycol) cholesterol ether: Liquid crystal phase behavior and luminescence properties
摘要： Biocompatible systems with luminescent properties attract significant interest as they are broadly used in bioanalysis and medical diagnostics. This paper describes new lanthanide liquid crystals based on an oxyethylated amphiphile with a cholesterol fragment (CholEO10). The complex of physicochemical methods (polarizing optical microscopy (POM), X-ray powder diffraction, FTIR-spectroscopy and luminescent analysis) was used to study liquid crystalline, structural and optical properties of these new biomesogens. Their phase behavior was compared with the behavior a lanthanum-containing analogue without a cholesterol fragment in its structure. A rigid hydrophobic fragment was found to exert a strong influence on lyotropic mesomorphism in aqueous media. The phase transition from a lamellar mesophase to a hexagonal one was observed with decrease of the CholEO10/La3+ complex concentration and addition of water. The study of luminescent properties of CholEO10/Ln3+ complexes, where Ln3+ is Dy3+, Tb3+, or Eu3+, revealed that their characteristic emission occurs in the yellow, green and red spectral ranges. Optical characteristics of new mesogens were estimated. Mesogenic CholEO10/Tb3+ and CholEO10/Eu3+ complexes demonstrate longer lifetime of their excited state as compared with the C12EO10/Ln3+/H2O complex.
关键词： Cholesterol derivatives,Liquid crystals,Luminescence,Poly(ethylene glycol),Lanthanide
更新于2025-09-23 15:21:21
-
Stretchable Hole Extraction Layer for Improved Stability in Perovskite Solar Cells
摘要： Flexibility and stretchability of solar cells are crucial factors for enhancing their real-life application for wearable devices. Although poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has been conventionally employed as a hole extraction layer (HEL) in flexible organic or perovskite solar cells, the inherent stretchability of PEDOT:PSS has yet to be convinced. Here, we report a highly stretchable and mechanically stable PEDOT:PSS-based thin film and its application on flexible perovskite solar cells. We synthesized a chemically linked copolymer, P(SS-co-TFPMA), consisting of PSS and tetrafluoropropylmethacrylate (TFPMA), followed by graft-copolymerization with poly(ethylene glycol) methyl ether methacrylate (PEGMA) to form a P(SS-co-TFPMA)-g-PEGMA dopant for the PEDOT HEL. The PEDOT:P(SS-co-TFPMA)-g-PEGMA (PEDOT:PTP) copolymer solution has excellent homogeneity and high phase stability and its developed HEL film exhibits outstanding stretching capability. After stretching of 300%, PEDOT:PTP films sustain conductivity of over 80% of its original conductivity whereas the conventional PEDOT:PSS films completely lose their conductivity after the strain of 300 %. In addition, the PEDOT:PTP incorporated flexible perovskite solar cells exhibited improved mechanical stability compared with the unassisted cells, retaining 92% of the initial power conversion efficiency after 1500 bending cycles at a 7 mm radius.
关键词： PEDOT:PTP,Stretchable,PEDOT:PSS,Hole extraction layer,Flexible,poly(ethylene glycol)methylacrylate
更新于2025-09-23 15:21:01
-
Poly(ethylene glycol)a??poly(propylene glycol)a??poly(ethylene glycol) and polyvinylidene fluoride blend doped with oxydianiline-based thiourea derivatives as a novel and modest gel electrolyte system for dye-sensitized solar cell applications
摘要： Unique symmetrical thiourea derivatives with an oxydianiline core were synthesized using cost-effective and simple methods. A new gel electrolyte system was prepared using these thiourea additives along with a highly conductive PEG–PPG–PEG block copolymer, PVDF, and an iodide/triiodide redox couple. The PEG units present in the electrolyte are well-known for their intense segmental motion of ions, which can degrade the recombination rate and favour the charge transfer. The thiourea additives interacted well with the redox couple to limit iodine sublimation and their adsorption induced a negative potential shift for TiO2. The highest efficiency attained by utilizing such gel polymer electrolytes was 5.75%, especially with 1,10-(oxybis(4,1-phenylene))bis(3-(6-methylpyridin-2-yl) thiourea) (OPPT), under an irradiation of 100 mW cm?2. The electrochemical impedance spectroscopy, UV-vis absorption spectroscopy, differential scanning calorimetry, and FTIR spectroscopy data of such gel polymer electrolytes favoured the PCE order of the additives used in DSSCs. The improvement in the DSSC performance with symmetrical thioureas having electron-rich atoms was practically attributed to the reduction of back electron transfer, dye regeneration, and hole transport.
关键词： Poly(ethylene glycol),poly(ethylene glycol),dye-sensitized solar cell,polyvinylidene fluoride,poly(propylene glycol),oxydianiline-based thiourea derivatives,gel electrolyte system
更新于2025-09-23 15:19:57
-
Chemical Synthesis and Characterization of Poly(poly(ethylene glycol) methacrylate)-Grafted CdTe Nanocrystals via RAFT Polymerization for Covalent Immobilization of Adenosine
摘要： This paper describes the functionalization of poly(poly(ethylene glycol) methacrylate) (PPEGMA)-grafted CdTe (PPEGMA-g-CdTe) quantum dots (QDs) via surface-initiated reversible addition–fragmentation chain transfer (SI-RAFT) polymerization for immobilization of adenosine. Initially, the hydroxyl-coated CdTe QDs, synthesized using 2-mercaptoethanol (ME) as a capping agent, were coupled with a RAFT agent, S-benzyl S'-trimethoxysilylpropyltrithiocarbonate (BTPT), through a condensation reaction. Then, 2,2'-azobisisobutyronitrile (AIBN) was used to successfully initiate in situ RAFT polymerization to generate PPEGMA-g-CdTe nanocomposites. Adenosine-above-PPEGMA-grafted CdTe (Ado-i-PPEGMA-g-CdTe) hybrids were formed by the polymer shell, which had successfully undergone bioconjugation and postfunctionalization by adenosine (as a nucleoside). Fourier transform infrared (FT-IR) spectrophotometry, energy-dispersive X-ray (EDX) spectroscopy, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy results indicated that a robust covalent bond was created between the organic PPEGMA part, cadmium telluride (CdTe) QDs, and the adenosine conjugate. The optical properties of the PPEGMA-g-CdTe and Ado-i-PPEGMA-g-CdTe hybrids were investigated by photoluminescence (PL) spectroscopy, and the results suggest that they have a great potential for application as optimal materials in biomedicine.
关键词： poly(poly(ethylene glycol methacrylate),CdTe quantum dots,adenosine,SI-RAFT,covalent immobilization
更新于2025-09-19 17:15:36
-
Amino-Functionalized Single-Walled Carbon Nanotubes-Integrated Polyurethane Phase Change Composites with Superior Photothermal Conversion Efficiency and Thermal Conductivity
摘要： The development of organic phase change materials (PCMs) with good shape stability, superior photothermal conversion efficiency, and high thermal conductivity is critical for practical photothermal utilizations. Herein, novel form-stable solar-thermal conversion and storage materials (SPCMs) with superior photothermal conversion efficiency and thermal conductivity were successfully synthesized by introducing amino-functionalized single-walled carbon nanotubes (SWNTs?NH2) into poly(ethylene glycol)-based polyurethane PCM. Differential scanning calorimetry (DSC) and thermal conductivity test results showed the SPCMs possessed relatively high phase change enthalpies in the range of 124.0?126.1 J/g and that the introduction of SWNTs?NH2 effectively enhanced the thermal conductivities of SPCMs. Sunlight irradiation experiments showed that the introduction of SWNTs?NH2 into PEG-based polyurethane PCM significantly improved the solar-thermal conversion and storage efficiency of SPCMs from 44.8% to 89.3%. The light irradiation cycling tests and thermogravimetric (TG) analyses indicated that the SPCMs exhibit satisfactory reversible stability and thermal stability. Moreover, SPCMs with SWNTs?NH2 added exhibited much higher solar-thermal conversion and storage efficiency and better reversible stability than SPCM with SWNTs added. In conclusion, the synthesized SPCMs show considerable potential for solar-thermal conversion and storage applications.
关键词： Poly(ethylene glycol),Solar-thermal conversion,Thermal energy storage,Single-walled carbon nanotubes,Phase change materials
更新于2025-09-19 17:13:59