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Poly(aryl amino ketone)-based materials with excellent electrochromic and electrofluorochromic behaviors
摘要： In recent years, electrochromic materials have attracted much attention for application in many fields, such as smart windows, mirrors, optical displays, and camouflage materials. Due to the advantages of short switching time, easy color-tuning, and high optical contrast ratio, polymer materials have great value for this research. In this work, a series of nonconjugated poly(aryl amino ketone) (PAAK)-based materials with carbazol-9-yl triphenylamine (CzTPA) units were designed and synthesized. These polymers were first used to research electrochromism (EC) and electrofluorochromism (EFC). In spite of the fact that they are nonconjugated polymers, they still exhibited some exciting electrochromic and electrofluorochromic performances, such as good switching time (the fastest speed can reach 1.91 s for coloring and 0.66 s for bleaching), high optical contrast (PAAK-tBu-CzTPA's highest Δ%T is 87% at 730 nm) and rapid fluorescence response (1.42 s for quenching).
关键词： Poly(aryl amino ketone)s,Electrofluorochromic,Electrochromic
更新于2025-09-23 15:21:21
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Mathematical modeling of heat distribution on carbon fiber Poly(ether-ether-ketone) (PEEK) composite during laser ablation
摘要： Since large amounts of energy are transferred precisely to the material in a very short time, laser and material parameters strongly affect the laser process quality. Mathematical modeling of heat distribution during cavity formation on carbon fiber reinforced PEEK composite material was performed. The temperature distribution equation has been obtained by the Fourier method. At the first stage, 1 J energy laser beam was sent onto the material and the cavity on the composite material was obtained. The constants in the temperature distribution equation obtained by making measurements over the cavity were found. Then the cavities were created with 2, 3 and 4 J laser beams to prove its reliability of the model. The results obtained from the measurement on the cavities and calculated from the temperature distribution equation were compared. Since the unidirectional carbon fibers were used, the obtained cavities have an elliptical shape. Verification experiments were carried out using two different heat conduction constants for in direction along fibers and perpendicular to carbon fibers. Experimental results and the mathematical model are in good agreement.
关键词： Mathematical modeling,Fourier method,Laser ablation,Fiber reinforced composites,Poly(ether-ether-ketone) (PEEK)
更新于2025-09-23 15:21:01
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Advances in Contact Angle, Wettability and Adhesion || Laser Surface Engineering of Polymeric Materials for Enhanced Mesenchymal Stem Cell Adhesion and Growth
摘要： Owing to them being relatively inexpensive and easy to manipulate, polymers are becoming more widely used within the biomedical industry for several different applications. As an example, because of its high wear resistance, low moisture absorption and high chemical resistance, poly(ether ether ketone) is commonly used as a biomaterial in the healthcare and biomedical industries. However, poly(ether ether ketone) surface properties are not optimum for efficient or enhanced bio-functionality, leading it to have somewhat inferior wettability and adhesion characteristics. On account of this, many researchers are now looking to employ surface engineering techniques to improve and enhance the surface properties of poly(ether ether ketone), enhancing its biomimetic nature and improving the bio-adhesion properties. This chapter discusses the importance of Mesenchymal Stem Cells (MSCs), the biological applications of poly(ether ether ketone) and the application of lasers for surface engineering of poly(ether ether ketone) for modifying mesenchymal stem cell response. Through the application of CO2 laser surface engineering it has been shown that laser surface engineering can have a positive effect on the rate of human mesenchymal cell growth, highlighting the opportunities for the healthcare and biomedical industries to adopt such technique. In addition, discussion of including poly(ether ether ketone) and other polymer materials as bio-composite materials for future research is introduced for enhancing material properties.
关键词： surface modification,surface engineering,poly(ether ether ketone),Mesenchymal stem cells,polymeric biomaterials,bio-engineering,laser treatment
更新于2025-09-11 14:15:04
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A facile synthesis of graphene nanoribbon-quantum dot hybrids and their application for composite electrolyte membrane in direct methanol fuel cells
摘要： In this work, we report the concept of synthesizing graphene nanoribbon-graphene quantum dot (GNR-GQD) hybrids with even grafting of GQD on GNR sheet in a facile single step process under ultrasonication in chlorosulfonic acid. Further, diazotization route is followed for the preparation of 4-benzenediazonium sulfonate precursor to sulfonate both GNR and GQD to form sulfonated graphene nanoribbons-sulfonated graphene quantum dots (sGNR-sGQD) nanohybrids. Synergistic and structure dependent effect of nanohybrids is seen via its dispersion in sulfonated poly(ether ether ketone) (sPEEK) to form nanocomposite membrane. sPEEK/sGNR-sGQD (1.5 wt. %) nanocomposite membrane shows remarkable direct methanol fuel cell (DMFC) performance compared to pristine sPEEK and Nafion 117 with 40 % increment in peak power density along with higher durability up to 100 h due to better physicochemical properties like water uptake, ion exchange capacity, proton conductivity, and reduced methanol crossover to suggest its potential which includes diverse membrane applications.
关键词： Graphene nanoribbon-graphene quantum dot hybrids,Nanohybrids,Nanocomposite membrane,Sulfonated poly(ether ether ketone),Direct methanol fuel cell
更新于2025-09-10 09:29:36
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Photocatalytic C(sp3)-H activation towards α-methylenation of ketones using MeOH as 1C source steering reagent
摘要： Unprecedented direct access to terminal enones via α-methylenation of aryl ketones to form C=C bond is achieved under visible-light conditions using methanol as one carbon source substrate and solvent as well. The reaction involves Cu@g-C3N4-catalysed in situ oxidation of methanol into formaldehyde followed by dehydrative cross aldol type reaction. Various aryl ketones react efficiently with MeOH, producing α,β-unsaturated carbonyl compounds only in 4-8 h at room temperature in excellent yield (84-97%). Operational simplicity, wide substrate scope, ambient reaction conditions, visible-light photocatalysis and novel application of MeOH as methylene donor substrate are the salient features making the envisaged protocol mild, efficient and green alternative to the existing methods for synthesis of such fine chemicals.
关键词： g-C3N4,1 C source,Ketone,Visible-light,Terminal enone
更新于2025-09-04 15:30:14