Amine‐Functionalized Polyglycidyl Methacrylate Microsphere as a Unified Template for the Synthesis of Gold Nanoparticles and Single‐Crystal Gold Plates

Polyglycidyl methacrylate (PGMA) microspheres, crosslinked and surface‐functionalized by amine, can be used as a solid‐state template for the synthesis of gold (Au) crystals in the forms of either nanoparticles (NPs) or plates. It is discovered that the polymer microsphere acts as an internal template to cultivate Au NPs inside the microsphere or an external template to generate the single‐crystal plates depending on the critical concentration (C_cr) of gold ions. The ion–dipole interaction and the structure‐dependent solubility of gold induce two distinct gold nanostructures in the presence of the functionalized polymer microspheres. The catalytic activity and long‐term storage of the developed gold nanostructures that can be easily scaled‐up for mass production through the developed novel methodology is demonstrated.     

Importance of domain purity in semi‐conducting polymer/insulating polymer blends transistors

Printed electronics is a rapidly developing field of research which covers any electronic devices or circuits that can be processed using direct printing techniques. Among those printing techniques, inkjet printing is a technique of increasing interest for organic field‐effect transistors (FETs) due to its fully data driven and direct patterning. In this work, the morphology of semi‐conducting polymer/insulating polymer blends from inkjet printing and their FET properties have been investigated. We attempted to optimize the morphology of the blends by the addition of a co‐solvent to the blend solution prior to film deposition. By varying the boiling temperature of the co‐solvent, blend films are fabricated with varying domain purity and different degree of semi‐conducting polymer ordering. The morphologies of all the as‐cast samples from inkjet printing and subsequently thermally annealed samples are characterized by grazing incidence wide angle x‐ray scattering and small angle neutron scattering. The results indicate that the sample where a low boiling temperature co‐solvent is used exhibits a lower degree of semi‐conducting polymer ordering and less pure domains, resulting in a decrease of hole mobility. The morphologies that are formed when high boiling temperature co‐solvent is used, however, give a higher degree of semi‐conducting polymer ordering along with higher domain purity, significantly improving hole mobility up to 1.44 cm² V^?1 s^?1 at V_DS = 40 V. More importantly, with thermal annealing, all the samples exhibit similar semi‐conducting polymer ordering and domain sizes while the domain purity significantly varies. This work is a unique example that demonstrates the importance of domain purity in the optimization of morphology and FET performance, which is previous unavailable. It also provides a novel process that can efficiently control the morphology of semi‐conducting polymer/insulating polymer mixtures during deposition to maximize FET performance from inkjet printing. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1760–1766     

喷墨打印聚合物薄膜均匀性调控研究进展

聚合物发光显示材料具有发光颜色在全可见光区可调、可溶液简单加工及适用于柔性大面积基底的特点,成为目前研究的热点。 在聚合物发光薄膜图案化技术中,喷墨打印因为具有加工过程简单高效、适用于溶液方式加工、柔性的加工过程等特点而被认为是最具有应用潜力的技术。 高质量聚合物薄膜的制备是高精度发光显示器件制作的关键,但喷墨打印液滴在干燥过程中通常伴随着“咖啡环”现象,造成薄膜不均匀沉积。 因此,消除“咖啡环”现象,实现聚合物薄膜的均匀沉积,是喷墨打印高性能器件的重要研究方向。 本文主要论述了“咖啡环”效应的产生机理,如何抑制喷墨打印聚合物薄膜加工过程中的“咖啡环”效应,最终实现聚合物薄膜均匀性调控。     

喷墨打印技术制备聚合物太阳能电池的研究进展

聚合物太阳能电池具有成本低、质量轻、容易制备大尺寸器件等优势,是太阳能电池研究中最为活跃的领域之一。喷墨打印技术作为新的成膜技术,具有材料利用率高、快速、可柔性加工等优点,已被用于聚合物太阳能电池的制备,发展潜力巨大。综述了聚合物太阳能电池、喷墨打印技术和喷墨打印技术制备聚合物太阳能电池的研究进展,同时对聚合物太阳能电...     

喷墨打印图案化高分子薄膜及其在有机电子器件加工中的应用

喷墨打印技术由于在图案化加工方面的高效、低成本、非接触形式及柔性的加工过程等特点而被应用于有机电子器件的加工中.通过打印功能性高分子溶液,喷墨打印实现了功能高分子薄膜的沉积和图案化,并实现了有机发光二极管、有机薄膜晶体管及其集成器件的加工.对喷墨打印在有机电子器件加工中取得的成果进行了总结,同时综述了高分子溶液喷墨打印过程中存在的基本科学问题和研究现状.     

Sonochemical Degradation of Gelatin Methacryloyl to Control Viscoelasticity for Inkjet Bioprinting

Inkjet printing enables the mimicry of the microenvironment of natural complex tissues by patterning cells and hydrogels at a high resolution. However, the polymer content of an inkjet-printable bioink is limited as it leads to strong viscoelasticity in the inkjet nozzle. Here it is demonstrated that sonochemical treatment controls the viscoelasticity of a gelatin methacryloyl (GelMA) based bioink by shortening the length of polymer chains without causing chemical destruction of the methacryloyl groups. The rheological properties of treated GelMA inks are evaluated by a piezo-axial vibrator over a wide range of frequencies between 10 and 10 000 Hz. This approach enables to effectively increase the maximum printable polymer concentration from 3% to 10%. Then it is studied how the sonochemical treatment effectively controls the microstructure and mechanical properties of GelMA hydrogel constructs after crosslinking while maintaining its fluid properties within the printable range. The control of mechanical properties of GelMA hydrogels can lead fibroblasts more spreading on the hydrogels. A 3D cell-laden multilayered hydrogel constructs containing layers with different physical properties is fabrictated by using high-resolution inkjet printing. The sonochemical treatment delivers a new path to inkjet bioprinting to build microarchitectures with various physical properties by expanding the range of applicable bioinks.     

A responsive poly(N-isopropylacrylamide)/poly(ethylene glycol) diacrylate hydrogel microsphere

A responsive hydrogel microsphere, which is constituted by poly(N-isopropylacrylamide)/poly(ethylene glycol) diacrylate, was fabricated in an aqueous two-phase system based on the polymer–polymer immiscibility. Characteristics of the hydrogel microsphere, such as the particle size and the morphology of freeze-dried or hydrated natural microspheres in water, tetrahydrofuran (THF)/H₂O (1:1 in volume) or acetone/H₂O (1:1 in volume), were investigated. The results showed that the swelling ratio and the particle size of the hydrogel microspheres were highly dependent on solvent composition. In addition, these characteristics were dramatically reduced when THF or acetone was added into the aqueous media. Scanning electron microscopy and environmental scanning electron microscopy micrographs also visually demonstrated that the regular spherical shape of the microspheres in water turned to irregular in shape when the microspheres were immersed in THF/H₂O or acetone/H₂O mixtures instead of pure water.     

Inkjet printed (bio)chemical sensing devices

Inkjet printing has evolved from an office printing application to become an important tool in industrial mass fabrication. In parallel, this technology is increasingly used in research laboratories around the world for the fabrication of entire (bio)chemical sensing devices or single functional elements of such devices. Regularly stated characteristics of inkjet printing making it attractive to replace an alternative material deposition method are low cost, simplicity, high resolution, speed, reproducibility, flexibility, non-contact, and low amount of waste generated. With this review, we give an overview over areas of (bio)chemical sensing device development profiting from inkjet printing applications. A variety of printable functional sensor elements are introduced by examples, and the advantages and challenges of the inkjet method are pointed out. It is demonstrated that inkjet printing is already a routine tool for the fabrication of some (bio)chemical sensing devices, but also that novel applications are being continuously developed. Finally, some inherent limitations of the method and challenges for the further exploitation of this technology are pointed out.     

沉淀聚合制备聚(季戊四醇三丙烯酸酯-苯乙烯)单分散微球及其形成机理

以季戊四醇三丙烯酸酯(PETA)作交联剂,苯乙烯作共聚单体,偶氮二异丁腈作引发剂,在乙醇或其与水的混合溶剂中沉淀聚合制备了交联聚合物微球.研究了反应时间、交联剂用量以及溶剂中水含量对聚合过程及微球的影响.结果表明当PETA用量在单体质量的5%-35%之间且反应时间不低于6h时可制得单分散聚合物微球.当PETA用量低于20%时,所得微球的粒径随PETA用量的增加逐渐减小,粒径分布逐渐变窄;此后继续提高PETA用量,微球粒径又逐渐增大,粒径分布逐渐变宽.向反应介质中加入水,可明显提高微球产率及单体转化率,但其体积分数达30%时,所得微球分散性变宽.在此基础上对微球的形成机理也进行了讨论.     

Picoliter droplet microfluidic immunosorbent platform for point-of-care diagnostics of tetanus

We have developed a sensitive, specific, rapid and low cost picoliter microsphere-based platform for bioanalyte detection and quantification. In this method, a biological sample, biosensing microspheres, and fluorescently labeled detection (secondary) antibodies are co-encapsulated to capture the analyte (here: human anti-tetanus immunoglobulin G) on the surface of the microsphere in microfluidic pL-sized droplets. The absorption of the analyte and detecting antibodies on the microsphere concentrate the fluorescent signal in correlation with analyte concentration. Using our platform and commercially available antibodies, we were able to quantify anti-tetanus antibodies in human serum. In comparison to standard bulk immunosorbent assays, the microfluidic droplet platform presented here reduces the reagent volume by four orders of magnitude, while fast reagent mixing reduces the detection time from hours to minutes. We consider this platform to be a major leap forward in the miniaturization of immunosorbent assays and to provide a rapid and low cost tool for global point-of-care.

Absorbance characterization of microsphere-based ion-selective optodes

Ionophore-based microsphere sensors are characterized here in transmission mode. These sensors contain a lipophilic ionophore for the analyte cation, a chromoionophore for recognizing H⁺, and a lipophilic cation-exchanger. They function on the basis of an ion-exchange equilibration step where an increased concentration of analyte ion leads to increased level of extraction into the bulk of the microsphere, expelling protons in return and deprotonating the chromoionophore. Since the path length is variable across the microsphere, such bead-based sensors are normally characterized in fluorescence mode. In this paper, the response of the sensing microspheres is calculated from the ratio of transmitted light intensities at the absorbance peak maxima of the protonated and unprotonated forms of the chromoionophore. At a fixed position of the particle, the resulting responses are found to be independent of light scattering, incident light intensity and the shape or size of the microsphere. The responses of potassium-selective microspheres obtained by this method agree quantitatively with corresponding fluorescence-based data.     

Gel kinetic characteristics and creep behavior of polymer microspheres based on bulk gel

Abstract

Deep profile control technology of polymer microspheres has become a widely used new method in improving oil recovery in heterogeneous reservoirs. The viscoelastic property of polymer microspheres plays an important role in the deformable migration behavior. In this study, a new method of measuring the viscoelastic properties of polymer microspheres based on bulk gel was proposed. Using mechanical rheometer and microrheometer, the effects on the storage modulus and gel performance were systematically researched. The creep-recovery test was applied to characterize the creep behavior of different polymer microsphere bulk gel. The results show that the storage modulus of polymer microspheres could be controlled by adjusting the agent concentration in the synthetic reaction. Moreover, the kinetic equation of gel time of polymer microspheres bulk gel and reaction temperature was established: ln(GT)?=?3289.18(1/T)-9.33. Elastic strain index was put forward as a new parameter to characterize the viscoelasticity of polymer microsphere in creep-recovery test. Finally, relationship between elastic strain index and storage modulus was constructed and a classification criterion of polymer microspheres with different viscoelasticity was proposed based on a large number of creep-recovery results. The research could provide a good theoretical guidance and technical support for the understanding of viscoelasticity of polymer microspheres.     

Fiber-optic array using molecularly imprinted microspheres for antibiotic analysis

In this article we describe a new class of high-density optical microarrays based on molecularly imprinted microsphere sensors that directly incorporate specific recognition capabilities to detect enrofloxacin (ENRO), an antibiotic widely used for both human and veterinary applications. This approach involves the preparation of highly cross-linked polymer microspheres by thermal precipitation–polymerization in the presence and absence of the target analyte ENRO to generate either molecularly imprinted (MIP) or non-imprinted polymer (NIP) microspheres, respectively. Each polymer type of tailor-made microsphere is fluorescently encoded with either coumarin-30 or tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(ii) dichloride [Ru(dip)₃]Cl₂ to enable the microspheres to be distinguished. The new MIP-based sensing platform utilizes an optical fiber bundle containing approximately 50 000 individual 3.1 μm diameter fibers that are chemically etched to create microwells in which MIP and NIP microspheres can be deposited and imaged using an epi-fluorescence microscope. The method enables multiplexed detection by independently addressing both types of beads through their separate light channels. The unique response to the presence of ENRO is manifested on the basis of a competitive immunoassay. A red-fluorescent dye-tagged ENRO, labeled with BODIPY® TR Cadaverine, competes with ENRO for specific binding sites. The developed immuno-like assay displayed a limit of detection (LOD) of 0.04 μM (10% binding inhibition) and a dynamic range of 0.29–21.54 μM (20–80% binding inhibition). The selectivity of the assay was evaluated by measuring the cross-reactivity of other fluoroquinolones (ciprofloxacin, norfloxacin, danofloxacin, and flumequine) and non-related antibiotics (penicillin G and doxycycline). This work demonstrates, for the first time, the applicability of MIPs, as an alternative to biomolecule receptors, for the development of multiplexed detection fiber-optic microarrays paving the way for a new generation of biomimetic sensors.     

Microencapsulation of bovine hemoglobin with high bio-activity and high entrapment efficiency using a W/O/W double emulsion technique

This study focused on the influences of solvent removal method and wall polymer composition on microspheres characteristics in W/O/W double emulsion procedure. Monomethoxypoly(ethylene glycol)-b-poly- -lactide (PELA) microspheres containing bovine hemoglobin (BHb, a model protein) were prepared by four solvent removal methods, including solvent-evaporation at atmosphere, at reduced pressure, solvent-extraction and solvent-diffusion methods, where the last method used ethyl acetate (EA) as organic solvent and the others used methylene chloride (MC). The bio-activity of encapsulated BHb, encapsulation efficiency, particle size and surface morphology of microspheres were evaluated in relation to the influences of solvent removal method and PELA composition. BHb encapsulated by the W/O/W double emulsion–solvent diffusion method with EA as organic solvent displayed a bio-activity near to that of native BHb. The efficiency of BHb entrapment achieved by this method was much higher than those by other methods (ca. 90% versus 30%). When using this process, the copolymers with MPEG 2000 block (molecular weight of PEG block: 2000 g/mol) yielded much higher efficiencies of BHb entrapment than those with MPEG 5000 block (90% versus 36%). Copolymer composition had less impact on microsphere size, but had a pronounced effect on surface morphology of microspheres. This study suggests that the W/O/W double emulsion–solvent diffusion method with EA as organic solvent is an effective process to prepare microspheres containing therapeutic proteins, and that the PELA copolymers containing MPEG 2000 block are promising wall material for biodegradable microsphere protein delivery system.     

Patterning catalyst via inkjet printing to grow single-walled carbon nanotubes

We demonstrated a method to pattern catalyst via inkjet printing to grow SWNTs, using metal salt solutions as the inks and an ordinary office-use printer. We printed water solutions of cobalt acetate on hydrophilic Si substrates and grew high quality SWNT films.     

作为细胞微载体的明胶基缓释微球的制备

用改良的乳化冷凝法制备载牛血清蛋白(BSA)的大粒径明胶微球. 结果表明, 明胶水溶液的质量分数为25%、水相与油相体积比3∶20、搅拌速度300 r/min、交联剂用0.1 mL质量分数为25%的戊二醛、 表面活性剂用0.1 g span-80为制备平均直径约250 μm明胶微球的理想条件. 所制备微球的后处理方法不同, 则明胶微球的表面形貌也不同, 细胞粘附率不同. 空白明胶微球在体外可以完全降解, 载BSA的明胶微球对BSA具有良好的缓释性, 释放时间可长达30 d. 显微镜观察成纤维细胞在明胶微载体上生长良好.     

Particle size limits for quantitative aerosol analysis using laser-induced breakdown spectroscopy: Temporal considerations

The temporal evolution of the Si atomic emission signal produced from individual silica microspheres in an aerosolized air stream was investigated using laser-induced breakdown spectroscopy (LIBS). Specifically, the temporal evolution of Si emission from 2.47 and 4.09-micrometer-sized particles is evaluated over discrete delay times ranging from 15 to 70 µs following plasma initiation. The analyte signal profile from the microspheres, taken as the silicon atomic emission peak-to-continuum ratio, was observed to follow the same profile of silicon-rich nanoparticles over the range of delay times. The ratio of analyte signals for the 2.47 and 4.09-micrometer particles was observed to be approximately constant with plasma decay time and less than the expected mass ratio, leading to the conclusion that further vaporization and enhanced analyte response do not continue with increasing delay times for these microsphere sizes. While recent research suggests that the temporal component of analyte response is important for quantitative LIBS analysis, the current study does confirm earlier research demonstrating an upper size limit for quantitative aerosol particle analysis in the diameter range of 2 to 2.5 µm for silica microspheres.     

纳米粒子的制备及其在打印印刷领域的应用

本文简要介绍了几类纳米粒子的制备及其在打印印刷领域的应用.包括无机纳米粒子复合材料用于绿色打印制版、聚合物乳胶纳米粒子用于喷墨打印制备光子晶体、金属纳米粒子用于印刷电路以及纳米材料用于3D打印,并展望了其发展前景.     

Preparation of quantum dots encoded microspheres by electrospray for the detection of biomolecules

In this paper, a novel method based on the electrospray technique has been developed for preparation of quantum dot (QD)-encoded microspheres for the fist time. By electrospraying the mixture of polymer solution and quantum dots solution (single-color QDs or multi-color QDs), it is accessible to obtain a series of composite microspheres containing the functional nanoparticle. Poly(styrene-acrylate) was utilized as the electrospray polymer materials in order to obtain the microsphere modified with carboxyl group on the surface. Moreover, to test the performance of the QD-encoded microsphere in bioapplication, it is carried out that immunofluorescence analysis between antigens of mouse IgG immobilized on the functional microsphere and FITC labeled antibodies of goat-anti-mouse IgG in experiment. To the best of our knowledge, this is the first report of QD-encoded microspheres prepared by electrospray technology. This technology can carry out the one-pot preparation of different color QD-encoded microspheres with multiple intensities. This technology could be also suitable for encapsulating other optical nanocrystals and magnetic nanoparticles for obtaining multifunctional microspheres. All of the results in this paper show that the fluorescence beads made by electrospray technique can be well applied in multiplex analysis. These works provide a good foundation to accelerate application of preparing microspheres by electrospray technique in practice.     

Inkjet printing of well-defined polymer dots and arrays

Inkjet printing represents a highly promising polymer deposition method, which is used for, for example, the fabrication of multicolor polyLED displays and polymer-based electronics parts. The challenge is to print well-defined polymer structures from dilute solution. We have eliminated the formation of ring stains by printing nonvolatile acetophenone-based inks on a perfluorinated substrate using different polymers. (De)pinning of the contact line of the printed droplet, as related to the choice of solvent, is identified as the key factor that determines the shape of the deposit, whereas the choice of polymer is of minor importance. Adding 10 wt % or more of acetophenone to a volatile solvent (ethyl acetate)-based polymer solution changes the shape of the deposit from ring-like to dot-like, which may be due to the establishment of a solvent composition gradient. Arrays of closely spaced dots have also been printed. The size of the dots is considerably smaller than the nozzle diameter. This may prove a potential strategy for the inkjet printing of submicrometer structures.