- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Photoconductive micro/nano-scale interfaces of a semiconducting polymer for wireless stimulation of neuron-like cells
摘要： We report multiscale structured fibers and patterned films based on a semiconducting polymer, poly(3-hexylthiophene) (P3HT), as photoconductive biointerfaces to promote neuronal stimulation upon light irradiation. The micro/nano scale structures of P3HT used for neuronal interfacing and stimulation include nanofibers with an average diameter of 100 nm, microfibers with an average diameter of about 1 μm, and the lithographically patterned stripes width of 3, 25 and 50 μm, respectively. The photoconductive effect of P3HT upon light irradiation provide electrical stimulation for neuronal differentiation and directed growth. Our results demonstrate that neurons on P3HT nanofibers showed a significantly higher total number of branches while neurons grown on P3HT microfibers had longer and thinner neurites. Such a combination strategy of topographical and photoconductive stimulation can be applied to further enhance neuronal differentiation and directed growth. These photoconductive polymeric micro/nano structures demonstrated their great potential for neural engineering and development of novel neural regenerative devices.
关键词： semiconductors,neurons,polymers,nanostructures,tissue engineering
更新于2025-09-23 15:23:52
-
Circularly Polarized Luminescence from Chiral Conjugated Poly(carbazole-ran-acridine)s with Aggregation-Induced Emission and Delayed Fluorescence
摘要： Pure organic materials with circularly polarized luminescence (CPL) and delayed fluorescence have gained increasing interest from academic and technological areas. To enhance the solid-state emission and exciton utilization in chiral optoelectronic devices, a synthetic strategy to impart conjugated polymers with CPL and aggregation-induced delayed fluorescence was proposed. Herein, two conjugated macromolecules with electron-donating poly(carbazole-ran-acridine) backbones, electron-withdrawing dibenzothiophen-2-yl(phenyl)methanone and chiral alanine moieties were designed and synthesized. Their neat films exhibited strong green emission with quantum yields of 6.7% and 10.3% and delayed fluorescence with lifetime of 1.358 μs and 1.366 μs, respectively. Both Cotton effect and CPL with dissymmetry factor of –2.01 × 10–3 and –1.39 × 10–3 were determined in the solid state. Such unique conjugated polymers were employed as solution-processed emitting layers in organic light emitting diodes, which displayed maximum brightness of 1477 cd/m2 and maximum current efficiency of 2.52 cd/A.
关键词： OLEDs,conjugated polymers,aggregation-induced emission,delayed fluorescence,aggregation-induced delayed fluorescence,circularly polarized luminescence
更新于2025-09-23 15:23:52
-
Chain End-Functionalized Polymer Brushes with Switchable Fluorescence Response
摘要： Herein is described the switchable fluorescence response of poly(methyl methacrylate) (PMMA) brushes. Chain end fluorescein labeled PMMA brushes are prepared by combining surface-initiated atom transfer radical polymerization (SI-ATRP) with a copper-catalyzed alkyne-azide cycloaddition (CuAAC) click reaction. Successful attachment of fluorescein is confirmed by measuring fluorescence of the as-prepared films. Utilizing co-solvency of PMMA in isopropanol-water mixtures, responsive behavior of the end-functionalized brushes is demonstrated by measuring the changes in fluorescence intensity between the swollen and collapsed states.
关键词： fluorescent polymers,polymer brushes,co-solvency,solvent responsiveness
更新于2025-09-23 15:23:52
-
Unprecedented Multicolor Photoluminescence from Hyperbranched Poly(amino ester)s
摘要： A novel kind of water-soluble fluorescent hyperbranched poly(amino ester) (PAE) is prepared through a one-pot polycondensation reaction of citric acid (CA) and N-methyldiethanolamine (NMDEA). The PAE exhibits enhanced and red-shift fluorescence with increasing solution concentration, showing distinct aggregation-induced emission character. Interestingly, the resulting PAE exhibits tunable photoluminescence from blue, cyan, and green to red irradiated by altering the excitation wavelengths. Such unique emission of non-conjugated PAE is attributed to the clustering of ester and tertiary amine groups derived from PAE self-assembly aggregates. Moreover, the fluorescence of PAE is very sensitive to Fe3+ ions. The facile preparation and unique optical features make PAE potentially useful in numerous applications such as multicolor cellular imaging, Fe3+ ions probe, and light-emitting diodes.
关键词： aggregation-induced emission,poly(amino ester)s,water-soluble polymers,hyperbranched,fluorescence
更新于2025-09-23 15:23:52
-
Photoelastic birefringence of copolymers with non-planar structure
摘要： We demonstrate the utility of nonplanar building blocks to tune the polymer photoelastic birefringence and obtain near zero and negative photoelastic coefficients. Photoelastic properties of two novel random copolymers systems: 2-vinlypyridene (2VP)-hydroxyadmantyl methacrylate (HAMA) and vinyl pyrrollidone (VP)-isobornylacrylate (iBOA) were investigated at a function of comonomer composition. Photoelastic coefficient of the copolymers could be facilely tuned by changing the copolymer composition. In particular, we show that negative stress optic coefficient could be obtained from VP - iBOA copolymers and near zero stress optic coefficient could be obtained from 2VP -HAMA copolymers. In addition, we investigate the effect of addition of triethylene glycol (TEG) as a plasticizer on the photoelastic properties for the 2VP-HAMA copolymers. We found that addition of TEG led to a reduction in both the polymer Tg and photoelastic coefficient. Our study indicates that bulky non-planar side groups in the polymer backbone tend to induce negative photoelastic birefringence and can be utilized as important building blocks for the design of optical polymers.
关键词： Optical polymers,Photoelasticity,Birefringence
更新于2025-09-23 15:23:52
-
Optically Responsive, Smart Anti-Bacterial Coatings via the Photofluidization of Azobenzenes
摘要： Antibacterial strategies sans antibiotic drugs have recently garnered much interest as a mechanism by which to inhibit biofilm formation and growth on surfaces due to the rise of antibiotic-resistant bacteria. Based on the photofluidization of azobenzenes, we demonstrate for the first time the ability achieve up to a 4 log reduction in bacterial biofilms by opto-mechanically activating the disruption and dispersion of biofilms. This unique strategy with which to enable biofilm removal offers a novel paradigm with which to combat antibiotic resistance.
关键词： photofluidization,azobenzenes,photoresponsive polymers,antibacterial and antifouling strategies,optically responsive materials,antibacterial coatings,smart materials
更新于2025-09-23 15:23:52
-
Tuneable thermal expansion of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate
摘要： The linear coefficient of thermal expansion for a mixture of poly(3,4-ethylenedioxythiophene) and polystyrene sulfonate (PEDOT:PSS) is calculated using density functional theory and the Debye-Grüneisen model. The linear coefficient of thermal expansion is a key factor in thermal management (thermal conductivity, thermal stress and thermal fatigue) of microelectronic and energy devices, being common applications of the conjugated polymeric PEDOT:PSS system. The obtained value of 53×10-6 K-1 at room temperature can be rationalised based on the electronic structure analysis. The PEDOT and PSS units are bonded by a dipole-dipole interaction between S in PEDOT and H in PSS. A C-C bond in a benzene ring (PSS) or thiophene (PEDOT) is up to 13 times stronger than the S-H bond. By adjusting the population of the S-H bonds by deprotonating PSS, the linear coefficient of thermal expansion can be enhanced by 57%. This allows for tuning the thermal properties of PEDOT:PSS in cutting-edge devices.
关键词： electronic structure,thermal properties,density functional theory,conjugated polymers
更新于2025-09-23 15:23:52
-
Modeling the Diffraction Efficiency of Reflective-Type PQ-PMMA VBG Using Simplified Rate Equations
摘要： A simulation based on the rate equations was performed to analyze the concentration distribution of molecules in phenanthrenequinone (PQ) doped polymethyl methacrylate (PMMA) polymers (PQ-PMMAs) exposed using a two-beam interference configuration. The concentration distributions were used to predict the diffraction efficiency of PQ-PMMA-based volume Bragg gratings (VBGs) by using the transfer matrix method. The simulation results suggest that an intermittent exposure method can promote the diffusion of PQ molecules and increase the final diffraction efficiency. A series of experiments validated our hypothesis that the diffraction efficiency of reflective-type PQ-PMMA VBG can be predicted.
关键词： Bragg gratings,holographic optical components,optical polymers
更新于2025-09-23 15:22:29
-
Efficient separation of photo-generated charges in a ferroelectric molecular wire: nonadiabatic dynamics study on 3,5-dicyano-1,7-dimethylopyrrolo[3,2-f]indole trimer
摘要： In this work we propose and verify computationally a novel idea of spontaneous separation of charges photo-generated in a highly polar molecular 'wire'. The nuclear and electronic structure of the investigated system, so as the evolution of charge carriers, are characterized at the semi-empirical OM2/MRCI level of theory. Results point to the conclusion that 90% of optically prepared excitons break into charge carriers (holes and electrons) localized on the opposite monomeric units of the trimer on the time scale of 30 fs. Our findings can be helpful in design of photoactive and conducting components for molecular photovoltaic applications.
关键词： ferroelectric polymers,nonadiabatic molecular dynamics,molecular photovoltaics,photo-generated charge separation,molecular wire
更新于2025-09-23 15:22:29
-
Porosity Determination of Carbon and Glass Fibre Reinforced Polymers Using Phase-Contrast Imaging
摘要： This paper presents multi-modal image data of different fibre reinforced polymer samples acquired with a desktop Talbot-Lau grating interferometer (TLGI) X-ray computed tomography (XCT) system and compare the results with images acquired using conventional absorption-based XCT. Two different fibre reinforced polymer samples are investigated: (i) a carbon fibre reinforced polymer (CFRP) featuring a copper mesh embedded near the surface for lightning conduction and (ii) a short glass fibre reinforced polymer (GFRP) sample. The primary goal is the non-destructive detection of internal defects such as pores and the quantification of porosity. TLGI provides three imaging modalities including attenuation contrast (AC) due to absorption, differential phase contrast (DPC) due to refraction and dark-field contrast (DFC) due to scattering. In the case of the CFRP sample, DPC is less prone to metal streak artefacts improving the detection of pores that are located close to metal components. In addition, results of a metal artefact reduction (MAR) method, based on sinogram inpainting and an image fusion concept for AC, DPC and DPC, are presented. In the case of the GFRP sample, DPC between glass fibres and matrix is lower compared to AC while DPC shows an increased contrast between pores and its matrix. Porosity for the CFRP sample is determined by applying an appropriate global thresholding technique while an additional background removal is necessary for the GFRP sample.
关键词： Porosity,Carbon and glass fibre reinforced polymers,Talbot-Lau grating interferometer,X-ray computed tomography,Differential phase contrast
更新于2025-09-23 15:22:29