三聚氰胺甲醛树脂壁微胶囊的研究进展

三聚氰胺甲醛树脂综合性能优异,近年来在微胶囊壁材领域得到了广泛应用。综述了以三聚氰胺甲醛树脂为壁材的微胶囊材料的研究现状。重点阐述了微纳米级相变储能材料、阻燃材料、有机颜料、自修复材料被三聚氰胺甲醛树脂微胶囊化后形貌及性能的变化。简要介绍了三聚氰胺甲醛树脂在微胶囊化农药、高能炸药、电子器件等材料的应用,同时总结了空心三聚氰胺甲醛树脂微胶囊最新的制备技术。展望了以三聚氰胺甲醛树脂为壁材的微胶囊在制备技术和性能改进上的可能的研究趋势。     

磁性显示微胶囊的同轴双喷头法制备

利用微胶囊技术,以海藻酸钠和明胶为壁材,四氧化三铁的混合溶液为芯材,采用同轴双喷头法制备了磁性显示微胶囊。考察了芯材溶液压强、壁材溶液压强、芯材溶液搅拌速度、喷头高度和喷头角度对微胶囊合格率的影响。结果表明,最佳制备参数为芯材压强175 kPa,壁材压强300 kPa,芯材溶液搅拌速度600 r/min,喷头高度40 cm,喷头角度35°。在最佳条件下制备出的磁性显示微胶囊粒径主要分布在100～250μm,内外表面光滑,囊壁透明,分散性好,形态完整,具有良好磁响应性。     

多彩液晶微胶囊的制备及性能研究

采用手性剂掺杂向列相混合液晶制备出具备类似胆甾相液晶温变显色性能的液晶混合物。通过控制向列相液晶中手性剂的添加量,调节混合液晶的颜色,制备出系列室温下呈颜色转变的液晶混合物。在此基础上,探究3种不同添加剂对混合液晶显色性能的影响,确定具备最佳温变显色性能的液晶混合物配方。以上述液晶混合物为芯材、异佛尔酮二异氰酸酯(IPDI)为壁材,采用界面聚合法在不同反应条件下制备出一系列液晶微胶囊,并确定最佳反应条件。结果表明:最佳反应条件下,制备的液晶微胶囊粒径范围在50～105μm之间,平均粒径在68.06μm左右,囊芯材料含量约占35%。液晶微胶囊呈规则球形,粒径比较均匀,具有良好的温变显色性能,且热稳定性较高,热分解温度达330℃以上。     

可逆示温微胶囊的制备及性能研究

采用油相分离法,以示温变色材料CoCl2·6H2O为芯材料,乙基纤维素、聚乙烯为壳材料,Span80为乳化剂,环己烷(HC)为溶剂,制备了可逆示温微胶囊.利用扫描电子显微镜、光学显微镜和热台偏光显微镜对可逆示温微胶囊进行了结构表征与性能分析,对所制备可逆示温微胶囊材料的耐疲劳性、耐溶剂性以及与高分子材料的相容性进行了研究,并重点就可逆示温微胶囊在油墨中的制备工艺、对油墨性能的影响进行了深入的研究与讨论.结果表明,所制备的微胶囊粒径均匀,平均粒径为4.5 μm.所制备的可逆示温丝网油墨具有优良的性能.     

一步法制备明胶-阿拉伯树胶电子墨水微胶囊

采用硬脂酸对TiO2纳米颗粒进行表面改性处理,以明胶-阿拉伯树胶为壁材,通过 一步复凝聚法制备了白色电子墨水微胶囊.傅立叶变换红外光谱仪及动态光散射仪分析表明,改性后的TiO2在四氯乙烯中具有良好的分散性.对分散体系进行微胶囊化处理后,颗粒能够均匀而稳定地分布在微胶囊内.调节明胶-阿拉伯胶用量、滴酸速度及浓度等,获得了无粘连、囊壁光滑、厚度可控的微胶囊.在10 V/靘的直流电场作用下,胶囊内改性TiO2纳米颗粒表现出良好的电场响应可逆移动特征.     

明胶-阿拉伯树胶电子墨水微胶囊显示性能优化

以明胶-阿拉伯树胶为壁材,四氯乙烯为分散介质,硬脂酸改性的TiO2为显示颗粒,采用复合凝聚法制备了红白显示的电子墨水微胶囊。详细讨论了TiO2用量对反射性能的影响,讨论了Span80用量对分散体系稳定性的影响。结果表明:随着电荷控制剂Span80用量的增加,颗粒的Zeta电势和电泳淌度随之增加,使得分散体系的稳定性增加。当Span80浓度为3.0%时,分散体系长时间放置,无沉降发生。制备的微胶囊涂膜后,器件的对比度及分辨率均得到了良好改善。同时,驱动电压可达2.5 V/μm,响应时间降低到150ms。     

微胶囊相变材料制备条件的优化

考察了乳化剂用量和搅拌速度对微胶囊相变材料制备的影响,通过测试证明：当乳化剂用量为9.4~9.8mL,搅拌速度为300r/min时,在三聚氰胺：甲醛=1：2.5,石蜡为10g,温度为80℃的条件下,制备得到的微胶囊相变材料包膜性能和分散性能较好。     

工艺参数对可逆示温微胶囊性能影响的研究

以乙基纤维素和聚乙烯为壳材料,热敏变色材料氯化钴为芯材料,Span80为乳化剂,采用油相分离法,对热敏变色材料氯化钴进行高分子材料包覆,制备了polyethylene/ethyl cellulose(PE/EC)可逆示温微胶囊.研究了壳材料用量、乳化剂用量、搅拌速率、相分离时间和环己烷用量等工艺参数对微胶囊的形成状态、包裹率等的影响规律,研究结果表明,工艺参数对微胶囊的变色温度影响不显著;随着相分离时间的增加,微胶囊的包裹率增大;随着搅拌速率的增加,微胶囊的包裹率呈先增大再降低的趋势.利用扫描电镜(SEM)和光学显微镜(OM)进行表征.微胶囊化的最佳试验条件为核壳比为1∶1, 相分离时间为3 h～4 h,搅拌速率为900 r/min.所制备的微胶囊极大地提高了可逆示温材料的变色灵敏性、环境适应性与高分子材料的相容性,具有良好的应用前景.     

原位沉积法制备脲醛树脂电子墨水微胶囊

以溶有油溶蓝的四氯乙烯为油相,以甲醛和尿素溶液为水相,分别利用明胶和聚乙烯醇作为改性剂,在不同pH条件下,利用一步原位沉积法制备出脲醛树脂微胶囊,方便快捷。用AJX-02型光学显微镜对微胶囊表面形貌、球形度、分散度及粒径进行表征。对合成的微胶囊分散液进行离心分离,计算包封率。结果表明,用聚乙烯醇作为改性剂,pH=2.0,乳化时间为60 min时制备出来的微胶囊表面光滑、球形度好,粒径分布在40～500μm范围内,平均粒径为320μm,脲醛树脂的包封率达到92%。     

新型热红外复合隐身涂层的研究

本文介绍了红外隐身技术实现的基本原理,探讨了新型热红外复合隐身涂层的制备工艺和初步性能测试,即发射率、降温性能、隔热性能的测试.作为降温材料,相变微胶囊的大规模制备,使得新型热红外隐身涂层的实现有了可能.实验结果为红外复合隐身涂料的实用化研究提供了重要参考.     

石蜡微胶囊化及其红外伪装隐身性能研究

用石蜡和脲醛树脂制备微胶囊相变材料,测试了微胶囊的各种性能,并对其在红外伪装隐身上的应用进行了研究．结果表明微胶囊相变材料既能够有效地模拟真目标的红外热特征,也能有效地遮蔽目标的红外热特征,具有红外隐真—示假的双重功能．     

Hydrogel Microcapsules with a Thin Oil Layer: Smart Triggered Release via Diverse Stimuli

A hydrogel microcapsule with an intermediate thin oil layer is presented to achieve smart release of a broad range of cargoes triggered via diverse stimuli. A microfluidic technique is used to produce triple emulsion droplets with a thin oil layer that separates the innermost aqueous phase from the hydrogel prepolymer phase, which transforms into a hydrogel shell via photopolymerization. The intermediate oil layer within the hydrogel microcapsule acts as an effective diffusion barrier, allowing encapsulation of various small cargoes within a porous hydrogel shell until a stimulus is applied to destabilize the oil layer. It is demonstrated that diverse stimuli including chemical dissolution, mechanical stress, and osmotic pressure can be utilized to release the encapsulated cargo on-demand. In addition, osmotic pressure and the hydrogel shell thickness can be independently tuned to control the onset time of release as well as the release behavior of multi-cargo encapsulated hydrogel microcapsule. The release can be either simultaneous or selective.     

Self‐Healing of an Epoxy Resin Using Scandium(III) Triflate as a Catalytic Curing Agent

A novel Lewis acid‐catalysed self‐healing system is investigated for implementation into epoxy‐based fibre reinforced polymer (FRP) composite materials. The catalyst, scandium(III) triflate, is selected using a qualitative approach and subsequently embedded with pre‐synthesised epoxy‐solvent loaded microcapsules, into an epoxy resin. Healing is initiated when microcapsules are ruptured at the onset of crack propagation. The epoxy monomer healing agent contained within actively undergoes ring‐opening polymerisation (ROP) on contact with the locally dispersed catalyst, forming a new polymer to bridge the two fractured crack planes. Self‐healing performance is quantified using a tapered double cantilever beam (TDCB) test specimen and the effects of microcapsule content and healing temperature and time are all independently considered. As an initial ‘proof of concept’ study, results show that a material recovery value of greater than 80% fracture strength is achieved for this novel Lewis acid‐catalysed self‐healing epoxy resin.     

Insights into Hierarchical Structure–Property–Application Relationships of Advanced Bacterial Cellulose Materials

Bacterial cellulose (BC) is an environmentally friendly biomaterial that is widely investigated because it possesses a unique hierarchical nanofiber network structure as well as extraordinary performance. In this review, the formation of the BC hierarchical nanofiber network structure from the perspective of biosynthesis is illustrated based on its basic chemical and crystal structure. Moreover, the design and processing of BC-based advanced materials through biosynthesis, physical, and/or chemical modification are also reviewed. The intrinsic characteristics of BC, derived from its hierarchical structure, are analyzed to understand its structure–property–application relationships. The applications of advanced BC-based materials are reviewed, such as high-strength structural materials utilizing the properties of nanofibers, energy conversion and storage, bioelectronic interfaces, environmental remediation, and thermal management applications utilizing the ion transport properties and 3D network structures of these materials. In addition, the authors also offer their opinions and potential future research directions for sustainably developing BC-based materials.     

GMM执行器电磁仿真与位移输出实验研究

超磁致伸缩执行器(GMA)具有驱动结构简单,响应快,输出力大等特点,在高性能电能-机械能与电能-液压能能量转换领域中具有广泛应用。该文分析了影响GMA位移输出的各个因素,首先介绍了GMA的工作原理及结构,随后对GMA进行电磁场仿真,比较不同线圈长度对GMA内部磁场强度分布的影响。最后搭建实验平台,分析了不同骨架材料、材料的不同处理方式及不同的预压力对GMA输出性能的影响。该文为设计高性能GMA提供参考准则,并总结出不同条件下GMA输出性能的优劣,为提高GMA性能及其结构优化提供可靠方案。     

Calcium Phosphate Microcapsules as Multifunctional Drug Delivery Devices

More challenging active pharmaceutical ingredients are entering the market, spurring the introduction of novel drug delivery strategies that necessitate a paradigm shift from exhausted excipients to materials with combined actions and multiple functionalities. In this study, an inorganic calcium phosphate microparticle with a hollow internal structure is introduced as a biocompatible and multifunctional microcapsule: the template inverted particle (TIP). A robust process is presented to create a unique particle geometry, which is characterized by a particle size of 20 µm and a hollow cavity enclosed by a specially engineered porous shell. This study focuses on the characterization of TIP as an excipient for the design of solid dosage forms. The cavities in the particle centers serve as an encapsulation space, resulting in boosted water uptake capacity of 5.3 cm³ g⁻¹. Benefiting from the material's high wettability and water uptake rates, TIP tablets immediately disperse in the oral cavity. Mechanistic studies reveal a viscoelastic behavior of empty TIP microcapsules in accordance with the Kelvin–Voigt model of a parallel spring-dashpot configuration. The unique particle geometry is maintained during compaction thanks to its exceptional structural integrity. This study demonstrates how multifunctional TIP microcapsules can be applied as a pharmaceutical drug delivery device.     

Recent Progress of Bismuth Effect on All-Inorganic Lead-Free Metal Halide Derivatives: Crystals Structure,Luminescence Properties,and Applications

Bismuth (Bi³⁺)-included lead-free metal halide (LFMH) materials attract much attention in lighting, display, photodetectors, X-ray detectors, and photovoltaic fields, due to the tunable luminescence and optoelectronic performance in response to crystal and electronic structure, morphology, and particle sizes. This review summarizes Bi³⁺-included LFMH materials about their preparation approach, crystal and electronic structure properties, luminescence performance, and emerging applications. Notably, Bi³⁺ ions not only can act as framework cation to construct stable LFMH structure, but can also incorporate into LFMH materials as activators or sensitizers to generate remarkable luminescence tuning and band engineering. The Bi³⁺ effect on the luminescence and optoelectronic properties of LFMH materials, including, promotion of exciton localization, enhancement of light absorption in near-ultraviolet region, action as sensitizer ions to transfer energy to rare earth or transition metal ions and emission of highly-efficient light is systematically summarized. The proposed structure-luminescence relationship offers guidance for the optimization of current Bi³⁺-included LFMH materials and the exploitation of new LFMH derivatives.     

红外探测II类超晶格技术概述(一)

本文简单归纳总结了红外探测II类超晶格材料的发展历史、基本理论、相比MCT材料的优势和材料的基本结构。通过设计6.1系超晶格材料适当的层厚和不同层间应力匹配的界面可以构筑灵活合理的能带结构,打开设计各种符合器件性能要求的新材料结构的可能性(如各种同质结p-i-n结构,双异质结DH、异质结W、M、N、BIRD、CBIRD、p-π-M-N、pBiBn、nBn、XBp、pMp等结构),还可以在一个焦平面阵列(FPA)像元上集成吸收层堆栈实现集成多色/多带探测。T2SL探测器可以满足实现大面阵、高温工作、高性能、多带/多色探测的第三代红外探测器需求,尤其在长波红外(LWIR)和甚长波红外(VLWIR)及双色/多带探测上可以替代MCT。     

Toward High Performance Thiophene‐Containing Conjugated Microporous Polymer Anodes for Lithium‐Ion Batteries through Structure Design

Poly(thiophene) as a kind of n‐doped conjugated polymer with reversible redox behavior can be employed as anode material for lithium‐ion batteries (LIBs). However, the low redox activity and poor rate performance for the poly(thiophene)‐based anodes limit its further development. Herein, a structure‐design strategy is reported for thiophene‐containing conjugated microporous polymers (CMPs) with extraordinary electrochemical performance as anode materials in LIBs. The comparative study on the electrochemical performance of the structure‐designed thiophene‐containing CMPs reveals that high redox‐active thiophene content, highly crosslinked porous structure, and improved surface area play significant roles for enhancing electrochemical performances of the resulting CMPs. The all‐thiophene‐based polymer of poly(3,3′‐bithiophene) with crosslinked structure and a high surface area of 696 m² g^?1 exhibits a discharge capacity of as high as 1215 mAh g^?1 at 45 mA g^?1, excellent rate capability, and outstanding cycling stability with a capacity retention of 663 mAh g^?1 at 500 mA g^?1 after 1000 cycles. The structure–performance relationships revealed in this work offer a fundamental understanding in the rational design of CMPs anode materials for high performance LIBs.     

深低温SiC空间反射镜背部与侧面支撑结构对比

在深低温下的反射镜及其支撑结构设计中,温度变化作用下的面形精度是空间反射镜性能的重要影响因素。以温度变化作用下的面形RMS为性能指标,基于碳化硅反射镜不同支撑结构和不同材料搭配形式下对空间反射镜的面形变化进行对比研究。首先,在深低温下对背部支撑和侧面支撑的以下两种情况进行仿真分析:(a)反射镜和支撑结构都用碳化硅制造;(b)反射镜用碳化硅制造,支撑结构用其他材料制造。仿真分析得到在(a)条件下背部支撑结构能获得更好的面形,在(b)条件下,侧面支撑结构能获得更好的面形;然后对侧面支撑结构中不同材料搭配情况下对面形精度的影响进行研究,对面形RMS与反射镜材料的线膨胀系数,支撑结构材料的线膨胀系数和反射镜材料与支撑结构材料的线膨胀系数之差的绝对值之间的关系用多元线性回归方法进行统计分析,研究其影响程度,分析得到线膨胀系数之差的绝对值对面形精度RMS的影响更大。研究取得的成果和研究思路对今后的深低温光学反射镜及其支撑结构设计提供参考。