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Effects of HEC Concentration on Silicon Polishing
摘要： Hydroxyethyl cellulose (HEC) is believed to effectively reduce haze level in silicon final polishing. We find that the removal rate(RR) and roughness of the polishing are very sensitive to the concentration of HEC, which can be divided into two concentration ranges. Its machanism is not only absorption occurence on silicon surface but also related to HEC colloid properties. Evidence has shown that HEC covers on the surface of silica sol, and there are three forms of coverage depending on the concentration, which have different effects on the interface between silicon and abrasive during polishing. Combined with steric hindrance, a possible polishing model is discussed based on the existence of HEC which is verifed by coeffiecient of friction force(CoF) according to HEC concentration. The results not only provide guidance for effective silicon polishing, but also imply that colloidal properties of additives with surface activity should be considered in other polishing systems.
关键词： Silicon wafer,Hydroxyethyl cellulose(HEC),Chemical-mechanical polishing(CMP)
更新于2025-09-10 09:29:36
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Recent advances in the manipulation of circularly polarised light with cellulose nanocrystal films
摘要： Significant advances have been made to control the iridescence and the selective reflection of left circularly polarised (LCP) light, and transmission of right circularly polarised (RCP) light of solid films prepared from cellulose nanocrystals (CNCs). However the manipulation of the photonic properties of the CNCs films, which reflect both RCP and LCP light is less investigated. Solid films prepare from natural sources as CNCs have advantageous characteristics that are absent in other synthetic structures, such as wide availability and renewability. Here we review and compare recent research activity involving the production and characterization of photonic band gap structures resulting from an anisotropic layer inserted between two cholesteric layers with different helical pitches but the same handedness. We make connections between systems existing in Nature and synthetic ones with the hope of advancing in the production and manipulation of CNCs-based photonic structures.
关键词： Cellulose nanocrystals,Photonics,Circularly polarised light,Bio-inspired materials,Iridescence,Liquid crystals
更新于2025-09-10 09:29:36
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Lectins at Interfaces—An Atomic Force Microscopy and Multi-Parameter-Surface Plasmon Resonance Study
摘要： Lectins are a diverse class of carbohydrate binding proteins with pivotal roles in cell communication and signaling in many (patho)physiologic processes in the human body, making them promising targets in drug development, for instance, in cancer or infectious diseases. Other applications of lectins employ their ability to recognize specific glycan epitopes in biosensors and glycan microarrays. While a lot of research has focused on lectin interaction with specific carbohydrates, the interaction potential of lectins with different types of surfaces has not been addressed extensively. Here, we screen the interaction of two specific plant lectins, Concanavalin A and Ulex Europaeus Agglutinin-I with different nanoscopic thin films. As a control, the same experiments were performed with Bovine Serum Albumin, a widely used marker for non-specific protein adsorption. In order to test the preferred type of interaction during adsorption, hydrophobic, hydrophilic and charged polymer films were explored, such as polystyrene, cellulose, N,-N,-N-trimethylchitosan chloride and gold, and characterized in terms of wettability, surface free energy, zeta potential and morphology. Atomic force microscopy images of surfaces after protein adsorption correlated very well with the observed mass of adsorbed protein. Surface plasmon resonance spectroscopy studies revealed low adsorbed amounts and slow kinetics for all of the investigated proteins for hydrophilic surfaces, making those resistant to non-specific interactions. As a consequence, they may serve as favorable supports for biosensors, since the use of blocking agents is not necessary.
关键词： lectin,gold,adsorption,bovine serum albumin,polystyrene,surface plasmon resonance spectroscopy,cellulose thin film
更新于2025-09-10 09:29:36
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Effects of laser surface texturing on tribological properties of Ti-6Al-4V in hydroxyethyl-cellulose water-based lubrication
摘要： Purpose – This paper aims to investigate the effect of laser surface texturing on the tribological performance of Ti-6Al-4V disks sliding against Si3N4 balls under hydroxyethyl-cellulose water-based lubrication. The friction coefficients and wear losses of textured and untextured disks were measured and compared. The results indicate that the texture patterns can lead to reduction of friction and wear in the condition of water-based lubrication. Design/methodology/approach – Solutions of hydroxyethyl cellulose were used as water-based lubricants. To find the optimal laser texturing parameters for the best performance enhancement, three line-like patterns were fabricated onto the disks and three machining parameters were used for each type of pattern. Tribological tests were conducted in rotation sliding with ball-on-disk contact configuration on UMT-2. Findings – A higher density of texture lines leads to a larger friction and wear reduction. Compared with untextured disks, the friction coefficient is reduced from 0.043 to 0.028 for textured disks. Some unworn parts were detected in the contact region of the balls against textured disks, which were not found on the balls against untextured disks. The worn surfaces indicated that periodic geometry of the contact track was rebuilt during run-in period, which was beneficial for the formation of lubricant films. Originality/value – In this work, laser surface texturing was used to reduce the friction and wear of Ti-6Al-4V specimens in water-based lubrication, which can be used to improve the tribological performance of Ti-6Al-4V components in mechanical equipment.
关键词： Ti-6Al-4V alloy,Hydroxyethyl-cellulose,Friction reduction,Laser surface texturing,Water-based lubrication
更新于2025-09-09 09:28:46
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Dual-emitting film with cellulose nanocrystal-assisted carbon dots grafted SrAl2O4, Eu2+, Dy3+ phosphors for temperature sensing
摘要： In this study, we synthesized a novel dual-emitting fluorescent phosphor from cellulose nanocrystal (CNC)-assisted carbon dots (CDs)-grafted SrAl2O4, Eu2+, Dy3+ (SAO) through a facile core-shell process. The CNC-CDs-coated SAO presents excellent scattered dual-emission and improved water resistance without destruction of the SrAl2O4 crystals. The phosphors were then reacted with coupling amino-silane and assembled with nanofibrillated cellulose skeletons to create flexible isotropic films. The obtained phosphors and hybrid films were characterized via electron microscopy, photoluminescence analysis, and X-ray photoelectron spectroscopy. The results demonstrate that the optical signals of phosphors can be controlled by CDs content. The assembled cellulose films exhibit strong temperature responses, high light-induced scattering, and good flexibility. The luminescent emission of films is highly sensitive to surrounding temperature variation (243 to 383 K) and good linearity behavior was obtained for such a sensitive sensor. Such flexible nanofibrillated cellulose films are excellent candidates for temperature sensor devices in industrial applications.
关键词： Cellulose,fluorescence,film,carbon dots,temperature
更新于2025-09-09 09:28:46
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Disappearance of Reflection Color by Photopolymerization of Lyotropic Cholesteric Liquid Crystals from Cellulose Derivatives
摘要： In this communication, we report on the disappearance of reflection color by photopolymerization of an acrylate monomer in lyotropic cholesteric liquid crystals from a cellulose derivative for color image applications. When a hydroxypropyl cellulose (HPC) derivative possessing propionyl side chains (HPC-Pr) was homogeneously dissolved in a liquid monomer of 4-hydroxybutyl acrylate (4HBA), we obtained lyotropic cholesteric liquid crystals (HPC-Pr_4HBA) with a Bragg reflection peak in the visible wavelength range. Such reflection wavelength was controllable by not only temperature, but also concentration of HPC-Pr in 4HBA. We found that Bragg reflection peak of lyotropic HPC-Pr_4HBA mixture disappears by photopolymerization of 4HBA, thereby leading to the fabrication of a photolithographic color image. This report provides promising clues to fabricate intriguing photonic devices adopted with cellulose derivatives by utilizing such Bragg reflection characteristics.
关键词： Color image,Cholesteric liquid crystals,Lyotropic liquid crystals,Cellulose,Bragg reflection,Photopolymerization
更新于2025-09-09 09:28:46
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Effects of mechanical stretching, desorption and isotope exchange on deuterated eucalypt wood studied by near infrared spectroscopy
摘要： Deuterium exchange combined with near infrared spectroscopy was used to study the roles of accessible and inaccessible cellulose in the load transfer of eucalyptus wood. Monitoring the drying process helped to assign bands of deuterated wood samples. Polarized NIR spectra of protonated and deuterated samples confirmed that inaccessible hydroxyl groups in eucalyptus wood were preferably oriented in the longitudinal direction. The spectral changes on NIR spectra caused by mechanical strain could be highlighted by averaging loading and unloading cycles to compensate for effects of desorption and isotope re-exchange due to environmental fluctuations. After deuteration, the bands affected by mechanical strain at around 6420, 6240 and 4670 cm-1, which had been assigned to hydroxyl groups in cellulose, remained at these positions, suggesting the inaccessible cellulose fraction was the main load-bearing component in wood. A small band at around 4700 cm-1 responding to mechanical strain, becoming visible in the deuterated spectra, indicated that accessible hydroxyls also contributed to the load transfer. Furthermore, the measurements confirmed previous reports of moisture adsorption of wood under tensile stress.
关键词： accessibility,tensile strain,deuterium oxide,cellulose,Eucalyptus regnans,dichroic ratio,hydroxyl groups
更新于2025-09-04 15:30:14
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Multivalent Biopolymer Capped Gold Nanoparticles as Stable and Non-Specific Endocytosis-Free Cell Labeling Agents
摘要： In this study, we report that carboxymethyl cellulose (CMC) is a stable capping agent for cellular labeling with gold nanoparticles (AuNPs). AuNPs were easily capped with CMC by simply mixing them and removing any unbound CMC by centrifugation. The CMC-capped AuNPs showed high stability in the presence of up to 100 mM of NaCl and (cid:1)-mercaptoethanol. Structural analysis of CMC-capped AuNPs revealed that multiple binding of CMC on AuNPs resulted in the stable protection. For specific cell labeling, anti-CD44 antibody was conjugated to CMC-capped AuNPs. Cellular labeling performance of the antibody-conjugated AuNPs was verified by adding these nanoparticles to HeLa cell containing culture. We observed light scattering spots from AuNPs inside HeLa cells, which were incubated with the antibody-conjugated AuNPs without non-specific endocytosis. However, clusters of citrate-capped AuNPs were found to be entrapped inside the cells through receptor-mediated endocytosis. In addition, no cytotoxicity was observed, confirming that CMC-capped AuNPs are useful as stable and biocompatible cell-labeling agents.
关键词： Endocytosis,Gold Nanoparticle,Darkfield,Carboxymethyl Cellulose,Cancer,Cellular Labeling Agent,CD44
更新于2025-09-04 15:30:14
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Usage of Cellulose Diacetate as Sorption Material for Fluorescent Analysis of PAH
摘要： Solid-phase matrices made of cellulose diacetate (CDA) as films and fibers were prepared. The CDA film matrices were found to be characterized by a negative value of the surface potential (–32 ± 2 mV) while the fibers had positive ones (+419 ± 1 mV). The possibility of using these matrices as sorption materials for luminescence analysis of polycyclic hydrocarbons in water-ethanol and micellar media is shown. Modification of such polymeric CDA matrices with surfactants of various natures improves their sorptive capacity and hydrocarbon recovery, and increases the sensitivity of luminescent analysis.
关键词： Ethanolic media,Surfactants,Fluorescent analysis,Polycyclic aromatic hydrocarbons,Cellulose diacetate,Aqueous micellar solutions
更新于2025-09-04 15:30:14
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Flexible photochromic cellulose triacetate based bionanocomposites modified with sol-gel synthesized V2O5 nanoparticles
摘要： Transparent and flexible bionanocomposites with photochromic properties based on cellulose triacetate (CTA) and sol-gel synthesized V2O5 nanoparticles were prepared. Poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) (EPE) triblock copolymer was added to achieve nanostructured materials and simultaneously control the dispersion of synthesized V2O5 nanoparticles. Investigated bionanocomposites were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), atomic force microscopy (AFM), tensile tests, and UV-Vis spectroscopy. FTIR results confirmed the presence of hydrogen bonds in the bionanocomposites. The miscibility between components improved with the increase of sol-gel content resulting in a decrease of the Tg and Tm of CTA phase as indicated by DSC results. Addition of EPE triblock copolymer enhanced the photochromic properties of bionanocomposites reducing the time of recovery to the initial state after 5 min of UV light irradiation. The biocompatibility of pure CTA and EPE/CTA blends as well as the photochromic properties provided by synthesized V2O5 nanoparticles make their transparent and flexible bionanocomposites ideal for possible future applications.
关键词： vanadium oxide,cellulose triacetate,photochromic properties,bionanocomposites,sol-gel
更新于2025-09-04 15:30:14