Photo-induced crosslinking of water-soluble polymers with a new photobase generator

A strong bicyclic guanidine base, 1,5,7-triaza-bicyclo[4.4.0]dec-5-ene (TBD), is photo-generated from its tetraphenylborate salt (TBD·HBPh₄) and can effectively catalyze the transesterification reaction between the ester and hydroxy groups in polymers. Accordingly, with TBD·HBPh₄ as a photobase generator, a water-soluble polymer blend, namely poly(1-vinylpyrrolidone-co-2-dimethylaminoethyl methacrylate) and 2-hydroxyethyl cellulose, has been developed as a potential eco-friendly photoresist. This photoresist system uses only water as a solvent and as a developer, rather than organic solvents and aqueous alkaline developers. The effects of the amount of photobase generator, polymer composition and photolithographic conditions on the photo-induced crosslinking and patterning of water-soluble polymers were studied.     

Two‐component photoresists containing thermally crosslinkable photoacid generators

Bis{4‐[2′‐(vinyloxy)ethoxy]phenyl}‐4‐methoxyphenylsulfonium triflate (TPS‐2VE‐Tf) and tris{4‐[2′‐(vinyloxy)ethoxy]phenyl}sulfonium triflate (TPS‐3VE‐Tf) were synthesized as thermally crosslinkable photoacid generators (PAGs) and used in a two‐component chemically amplified photoresist system. The photoresist films formulated with poly(p‐hydroxystyrene) (PHS) as a binder polymer and a thermally crosslinkable PAG are insolubilized in aqueous base by prebaking due to the thermal crosslinking reaction between PHS and the PAG. The insolubilization temperature of the resists and conversion of vinyl ether groups are greatly influenced by the PAG concentration and prebaking temperature, respectively. Upon exposure to deep UV and subsequent postexposure bake, the crosslinks are cleaved by photogenerated acid, leading to effective solubilization of the exposed areas. Photoresists containing TPS‐2VE‐Tf and TPS‐3VE‐Tf exhibited sensitivities of 12 and 45 mJ/cm², respectively. Positive‐tone images were obtained using a 2.38 wt% aqueous tetramethylammonium hydroxide developer.     

Synthesis and characterization of liquid crystal photoresist

A thermotropic liquid crystal polymer with photosensitive groups (liquid crystal photoresist), copoly(4-methoxyphenyl) 4′-(2″-acroloyloxy ethoxy) benzoate (MPAEB)-4-vinylbenzyl cinnamate (VBC) was prepared, and its thermal behavior was characterized by a differential scanning calorimetry. The copolymer exhibited a liquid crystal mesophase between approximately 70°C and 120°C. In the mesophase, poly(MPAEB-VBC) (85/15) had a higher photo-crosslinking ability than that at room temperature and at 140°C, where the copolymer exhibited the isotropic phase. It was found that the liquid crystal photoresist had a high crosslinking ability owing to alignment of its photosensitive groups. © 1994 John Wiley & Sons, Inc.     

The free radical polymerization of vinyl monomers in the presence of carbon black

The polymerization of vinyl monomers has been carried out in the presence of furnace blacks using initiators such as 2,2′-azobisisobutyronitrile (AIBN) and benzoyl peroxide (Bz₂O₂) in nitrogen or oxygen atmosphere. The results indicate that free radicals form by the decomposition of initiators reacting with carbon blacks to give active sites on their surface which then capture either the free radicals or the growing polymer radicals. Using the monomers with negative e values, such as styrene and vinyl acetate, a marked retardation was observed in Bz₂O₂-initiated polymerization in the presence of furnace blacks, while a moderate inhibition was found in the polymerization initiated by AIBN. The polymerization reaction using Bz₂O₂ was found to be very sensitive to oxygen in the presence of furnace blacks and the involvement of oxygen was found to promote grafting onto the surface of carbon black by the growing polymer radicals, consequently giving polymer-grafted particles while hindering the formation of homopolymers. Furthermore, the reaction of Bz₂O₂ with the surface of furnace blacks in oxygen atmosphere has been studied in carbon tetrachloride at 45°C. The resulting carbon blacks show an increase in the number of surface quinone groups with an increase in reaction time.     

The competitive reactions of initiator fragments and growing polymer chains against the surface of carbon black

The reactivity of free radicals generated by the thermal decomposition of 2,2′-azobisisobutyronitrile (AIBN) is compared with that of the free radicals from 2,2′-azobis-2,4-dimethyl valeronitrile in nitrogen atmosphere at 60°C, and the reaction mode of the free radicals with carbon black surface is discussed. Also bulk polymerization of vinyl monomers such as styrene and methyl methacrylate was performed in the presence of furnace black in nitrogen at 60°C using AIBN as initiator. Typical retardation is found in the course of conversion of methyl methacrylate into the polymer, whereas inhibition is observed in the conversion of styrene which results in an induction period of the reaction. In addition, inhibition by carbon black is also found in the copolymerization of methyl methacrylate with a small amount of styrene. On the basis of the results of the conversions of different kinds of monomers, competitive reactions of 2-cyano-2-propyl radicals from AIBN and growing polymer radicals are suggested to occur preferentially on the surface of carbon black. The results are supported by the observation of the stability of the dispersion of the resulting carbon black in adequate solvents and also by gas chromatographic analysis of the pyrolysis products of the polymers bound to the surface of carbon black.     

Einfluß der Stabilisatorkonzentration auf die Oxidationsgeschwindigkeit vernetzter Polydiene

The oxidation rate V_ox of unfilled vulcanizates with different network structures was investigated as a function of the concentration of added antioxidants with the general formula AH, namely 2,2′-methylene-bis(6-tert-butyl-4-methylphenol), N-phenyl-2-naphthylamine and N,N′-diphenyl-p-phenylenediamine. The oxidation rate can be described by the empirical equation: Using a?ines x has a value of 1, for the bisphenol a value of 0.5 was found. The first term is caused? by a chain termination reaction in which a peroxy radical abstracts the reactive hydrogen of AH. The second term relates to O₂ attack on antioxidant, probably with formation of free radicals. This reaction is dependent on oxygen pressure and in the case of 2,2′ -methylene-bis(6-tert-butyl-4-methylphenol) of minor importance. The term c is dependent on network structure but its contribution to v_ox is negligible     

Optimisation of the synthesis of a water-soluble sulfur black dye

A water-soluble sulfur black dye containing carboxylic acid groups was prepared by reducing C.I. Sulfur Black 1 to its leuco form followed by reaction with chloroacetic acid. In conducting this reaction, variables studied included the order of adding reactants, the amount of Na₂S and chloroacetic acid employed, and the time and temperature of the reaction. It was found that the carboxylic acid group content and reaction yield were maximized by controlling the amount of Na₂S and chloroacetic acid employed, and by conducting the reaction for 2 h at 60 °C.     

水溶液型醋酸钴催化剂的工业运用研究

本文介绍了水溶液型醋酸钴催化剂在仪化年产33万t的PTA装置上的试用情况,试用过程中发现催化剂中黑色沉淀物可以抑制PX氧化主反应,促进燃烧副反应,影响产品质量和装置正常操作。     

Plasma-assisted supercritical carbon dioxide removal process for photoresist stripping applications

Because of increasing interest in environmentally benign fabrication process, the use of dry cleaning processes to remove residues of metal, photoresists, organic moieties and particles from surfaces has grown as a research area. In this study, we designed series of systematic approaches to understand the properties of the hard-baked photoresist on glass substrates. We focused on the effects of de-bonding photoresists on the surface by using a plasma-assisted supercritical carbon dioxide removal process with various control parameters. Changes in the surface morphology of plasma de-bonded photoresists were observed and analyzed. A weight-loss method was used to evaluate quantitatively the efficiency of photoresist stripping by SCCO₂. Compared to the blank experiment (SCCO₂ process only), the photoresist residue reduces to 14.7% from 76.3%. This study demonstrates the possibility of incorporating plasma pretreatment into the supercritical carbon dioxide removal process for photoresist stripping applications.     

Effect of temperature on the SU-8 photoresist filling behavior during thermal nanoimprinting

SU-8 photoresist is an ideal thermal-imprinting polymer, which has been widely used in micro-nano devices in recent years. However, the research on the filling behavior of SU-8 photoresist during thermal nanoimprinting is not complete. In this paper, the stress relaxation curves and shear stress/rate flow curves were measured to analyze the temperature dependent rheological properties of SU-8 photoresist. The filling behavior of SU-8 photoresist was discussed based on thermal imprinting results at various temperatures. High-precision nanochannels were fabricated with replication error of 2.8% at optimized thermal imprinting temperature of 85°C and duration of 10 min, which paves the way for high-precision fabrication of SU-8-based micro-nanofluidic chips.     

光刻胶用环化聚异戊二烯的研制

研究了顺１，４聚异戊二烯在二甲苯溶剂中在酸性复合催化剂ＳｎＣｌ４／ＰＴＳＡ存在下的环化反应。发现复合催化剂可在较低的温度下引发聚异戊二烯的环化反应，且可抑制聚合物的降解反应，找到了复合催化剂的最佳组成。制得了适用于光刻胶制造的环化聚异戊二烯。     

Crystallography and Structure–Property Relationships in 2,2′,2″,2′′′,4,4′,4″,4′′′,6,6′,6″,6′′′‐Dodecanitro‐1,1′ : 3′1″ : 3″,1′′′‐ Quaterphenyl (DODECA)

X‐ray crystallographic study of 2,2′,2″,2′′′,4,4′,4″,4′′′,6,6′,6″,6′′′‐dodecanitro‐1,1′ : 3′1″ : 3″,1′′′‐quaterphenyl (DODECA) has been carried out. Nonbonding interatomic distances of oxygen atoms inside of all the nitro groups are shorter than those corresponding to the intermolecular contact radii for oxygen. By means of the DFT B3LYP/6‐31(d, p) method a difference of 136 kJ mol⁻¹ between the X‐ray and DFT structures of DODECA was found. The bearer of the highest initiation reactivity in its molecule in solid phase should be the nitro group at 4′′′‐position, in contrast to those at 2′‐ or 2″‐positions in its isolated molecule. The most reactive nitro group in the DODECA molecule can be well specified by the relationship between net charges on nitro groups and charges on their nitrogen atoms, both of them for the X‐ray structure. The ¹⁵N chemical shift, corresponding to this nitro group for the initiation by impact and shock, correlates very well with these shifts of the reaction centers of the other six “genuine” polynitro arenes.     

甲基丙烯酸酯类光刻胶成膜树脂的合成与性能研究

以甲基丙烯酸(MAA)、甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)为单体,偶氮二异丁腈为引发剂,采用溶液自由基聚合方法,合成了甲基丙烯酸酯类光刻胶成膜树脂,研究了合成工艺对产物分子量及分子量分布的影响,并对其在光刻胶中的应用性能,如碱溶性、涂膜表面干燥性、感度和分辨率等进行了初步考察。结果表明,在引发剂用量为单体用量的0.6%~1%、反应温度80~85℃、3次进料条件下,制得的聚合物的重均分子量为44 341~53 696,分子量分布为3.66~5.69,由单体质量比MAA∶MMA∶BA为25∶50∶25的成膜树脂配制的光刻胶,分辨率达35μm。     

A Simple Strategy to Achieve Mussel‐Inspired Highly Effective Antibacterial Coating

Although significant progress has been made in the preparation of mussel‐inspired antibacterial coatings, continual challenges still remain in pursuing more facile and simpler fabrication methods to construct more robust and effective coatings. In this study, quaternized catechol (QCat), which is synthesized via a simple quaternization reaction from two commercially available materials, 2‐chloro‐3′,4′‐dihydroxyacetophenone and N,N‐dimethyldodecylamine, is used as a reactive antimicrobial agent to fabricate mussel‐inspired antibacterial coatings. Specifically, QCat reacts with branched polyethyleneimine (PEI) in Tris‐HCl solution through a cross‐linking reaction between amino and catechol groups to form a homogeneous coating on various substrates via a simple co‐deposition process. The formed PEI/QCat coating exhibits highly effective antimicrobial activity against both Staphylococcus aureus and Escherichia coli and good adhesion on glass, metal, and plastic substrates. Such a simple fabrication process makes it a potential candidate for industrial and medical applications.     

酚醛-重氮萘醌正性抗蚀剂溶解抑制机理

本文综述了酚醛-重氮萘醌正性抗蚀剂的溶解抑制机理，主要包括(1)分子间氢键作用机理；(2)偶联反应机理；(3)两步即静态、动态溶解抑制机理；(4)表面沉积溶解抑制机理；(5)酚醛树脂的分子溶解及相关的抑制机理．     

Electrospray Deposition of Photoresist: A Low Impact Method for the Fabrication of Multilayered Films

Electrospray deposition has been investigated as a substitute for photoresist spin coating. The morphology of Microposit S1813 photoresist films has been studied as a function of several spray conditions including resist concentration, substrate surface, and flow rate. Film morphology is controlled by three process parameters: the surface energy determines the equilibrium conditions of resist on the substrate; the viscosity and volume flux determine the relaxation time for the depositing resist solution after impact on the substrate. Electrosprayed photoresist films have been used for photolithographic patterning and it has been demonstrated that electrospray deposition is an effective method for deposition of photoresist on top of fragile, thin films, which can be used for multilayered thin film fabrication.

     

纤维素低氧环境下热解特性和糖类生成机制

在最小化二次反应的金属网反应器下对微晶纤维素进行低氧热解实验。采用带有脉冲安培检测的高性能阴离子交换色谱法(HPAEC-PAD)的Dionex ICS-6000离子色谱(IC)对热解后的产物水溶性中间态活性纤维素(WSIAC)和水溶性初生焦油(WSPT)的组成和分布进行分析。重点关注纤维素热解过程中几种脱水糖和糖聚物的生成转化规律。实验发现氧气通过促进中间态纤维素的生成来提前纤维素的分解。氧化气氛下,聚合度越高的脱水糖稳定性越差。氧气的存在一方面促进纤维二聚糖和纤维三聚糖生成,另一方面,它们的破碎或其他分解反应也在一定程度下受到氧气影响。     

Hydrothermal synthesis of α-MnO2/MIL-101(Cr) composite and its bifunctional electrocatalytic activity for oxygen reduction/evolution reactions

An α-MnO₂/MIL-101(Cr) composite catalyst was synthesised using a hydrothermal process. In this composite, α-MnO₂ nanoparticles are embedded in an MIL-101(Cr) matrix with abundant micropores and a high specific surface area, which improves the reactant's accessibility to catalytically active sites, resulting in a significant improvement in oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in an alkaline electrolyte. The strong interactions between α-MnO₂ nanoparticles and MIL-101(Cr) matrix result in a high structural stability and therefore excellent activity stability.     

铬铁酸浸液除铁过程的草酸亚铁回收及铁黑颜料制备

对铬铁酸浸液除铁所得草酸亚铁进行氧气氧化-氨浸处理,回收除铁剂草酸盐并用其制备氧化铁黑颜料. 考察了氨水用量、反应温度、液固比、反应时间、氧气流量、反应液pH值及晶化温度等对C2O42-浸出率和氧化铁黑质量的影响. 结果表明,反应液经60℃晶化处理后,在反应温度80℃、氨水与草酸亚铁摩尔比为3、液固比5 mL/g、氧气流量0.1 L/min、pH值6.9~7.4、反应时间3 h的条件下,C2O42-的浸出接近100%,得到的氧化铁黑质量与国产722氧化铁黑产品相当.     

Anwendung von Ethoxyquin zur Qualitätserhaltung pflanzlicher Produkte

Application of Ethoxyquin for the Quality Preservation of Plant Products The use of the antioxidant ethoxyquin in plant products leads to ethoxyquin residues and many degradation and reaction products. The compound M₁, probably a primary reaction product, was identified as 1,1′,2,2′-tetrahydro-2,2,2′,2′,4,4′-hexamethyl-6,6′-diethoxy-1,8′-biquinoline by means of UV, IR and ¹H-NMR spectroscopy and by mass spectrometry. Two other degradation products were found to be oligomeric or polymeric compounds which, beside the ethoxyquin monomer, also contained structural elements formed by oxidative ring cleavage of the heterocycle. The predominating reaction, however, is the covalent binding of ethoxyquin to lignin. Regarding the mechanism of action of ethoxyquin, these studies have shown that ethoxyquin acts not only as a radical scavenger, but that it also binds oxygen by varying reactions.