Designing Semipermeable Hydrogel Shells with Controlled Thickness through Internal Osmosis in Triple-Emulsion Droplets

Hydrogel shells that compartmentalize the water core from the aqueous surrounding provide molecular selectivity on size and charge in transmembrane transport. It is highly demanding to produce thin hydrogel shells to minimize diffusion length and maximize core volume. Here, internal osmosis in water-in-oil-in-water-in-oil (W/O/W/O) triple-emulsion droplets is used to produce thin hydrogel shells enclosing a large water core. The triple-emulsion droplets are prepared to have an ultrathin middle oil layer using a capillary microfluidic device. The innermost water droplet has a higher osmolarity than the outer water layer containing photopolymerizable hydrogel precursors, which pumps water from the outer layer to the core through the ultrathin oil layer by the osmosis. Therefore, the outer layer gets thinner and hydrogel precursors are enriched while the size of the triple-emulsion droplets remains unchanged. Through photopolymerization of precursors and phase transfer from oil to water, hydrogel shells enclosing water core are produced in the water environment; the oil layer is ruptured for molecular exchange through the shells. The thickness and composition of the hydrogel shells are precisely controllable by the osmotic conditions. The shells show a high permeation rate due to the thinness as well as controlled cut-off threshold of permeation for neutral and charged molecules.     

Preparation and characterization of polyurethane microcapsules containing n‐octadecane with styrene‐maleic anhydride as a surfactant by interfacial polycondensation

A series of polyurethane microcapsules containing a phase change material (PCM) of n‐octadecane was successfully synthesized by an interfacial polymerization in aqueous styrene‐maleic anhydride (SMA) dispersion with diethylene triamine (DETA) as a chain extender reacting with toluene‐2,4‐diisocyanate (TDI). The average diameter of microPCMs is in the range of 5–10 μm under the stirring speed of 3000–4000 rpm. Optical and SEM morphologies of microPCMs had ensured that the shell was regularly fabricated with the influence of SMA. FTIR results confirmed that the shell material was polyurethane and the SMA chains associated on core material reacted with TDI forming a part of shell material. The shell thickness was decreasing in the range of 0.31–0.55 μm with the molar ratio of DETA/TDI from 0.84 to 1.35 and the weight of core material increasing from 40 to 80% (wt %). By controlling the weight ratio of PCM as 40, 50, 60, 70, and 80% in microPCMs, it was found using DSC that the T_m and T_c of microPCMs were in the range of 29.8–31.0^oC and 21.1–22.0°C and an obvious phase change had been achieved nearly the same temperature range of that of PCM. The results from release curves of microPCM samples prepared by 1.4, 1.7, and 2.0 g of SMA indicated the release properties were affected by the amount of the dispersant, which attributed to the emulsion effect and shell polymerization structure. The above results suggest that the shell structure of microPCMs can be controlled and the properties of microPCMs determined by shell will perform proper practical usage. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4996–5006, 2006     

缓香型玉米醇溶蛋白微胶囊乳液的制备及应用

为改善皮革的特殊气味并提升其应用性能,该研究以玉米醇溶蛋白（Zein）、艾叶香精（AAE）以及普兰尼克F127等为原料,通过反溶剂法制备缓香型玉米醇溶蛋白微胶囊（AAE@ZMs）乳液,再将AAE@ZMs乳液与成膜剂己内酰胺改性酪素复配后应用于皮革涂饰。结果表明,Zein与F127、AAE和戊二醛通过化学交联和氢键相互作用,同时F127和AAE可使Zein中的氨基酸重排并发生荧光猝灭;制得的AAE@ZMs乳液中微胶囊平均粒径约为298.6 nm且具有较好的分散性和稳定性;AAE@ZMs的包覆率和负载率分别可以达到73.2%和5.8%,在良溶剂中释放120 h时的AAE累积释放率约为83.1%。将AAE@ZMs应用于皮革涂饰后,涂饰革样中AAE的释放周期为6周,对金黄色葡萄球菌和大肠杆菌均具有较好的抑制效果,同时涂饰革样还展现出较好的机械性能。     

不同分散染料微胶囊的制备及应用

采用原位聚合法进行双层造壁，对不同结构的分散染料进行胶囊化。将分散染料高速均化后，在pH=4～6时加入TMM，65℃保温1．5小时，再滴加一定量PEHMM，在75℃时保温2.5小时进行双层造壁、C.I.分散橙30染料胶囊的粒径平均值为13．53μm，中值8．732μm；C.I．分散蓝56微胶囊粒径平均值为36.3μm，中值24.87μm。胶囊染色结果显示：这两只染料性能优于传统染料，染色后其废液的吸光度分别为0.021和0.003，比传统染色废水的1.286和0.786低很多。     

离子取代凝胶——ACA离子取代动力学模型

用动边界模型描述了海藻酸-壳聚糖-海藻酸(ACA)离子取代凝胶对2价离子的取代动力学过程.模型具有较好的可靠性，ACA离子取代凝胶对2价离子的取代属于颗粒扩散控制.ACA离子取代凝胶对Pb²⁺的反应级数是0.76.     

热敏微胶囊热响应特性研究

将热敏微胶囊作为基本显影单元,影像稳定性和分辨率得到了提高,影像形成速度也更符合数字化成像的要求。本文结合热敏技术、微胶囊技术,将染料前体微胶囊化,制备出粒径在1μm以下的热敏微胶囊。测量了囊壁的玻璃化温度,对显影后的影像进行了对比,测量了不同显影温度下的影像密度,分析了影像密度随显影温度变化的关系。     

Synthesis and characterization of polyurea microcapsules containing essential oils with antigerminative activity

In this paper we report on the preparation and characterization of polyurea‐based microencapsulated systems, containing essential oils as core materials, for potential applications in controlled‐release formulations of agrochemicals. Microcapsules were synthesized by interfacial polymerization in o/w emulsion between polyfunctional isocyanates and diamines, to investigate the effect of the monomer kind on the morphology and properties of the produced samples. The synthetic conditions that gave the best results were used to microencapsulate four essential oils, able to interfere with the seed germination and radicle elongation of some test plants. The produced samples were characterized, with the aim to analyze their morphology and to verify the effectiveness of essential oil microencapsulation. Moreover, preliminary bioassay based on seed germination and subsequent radical growth were carried out to study the effects of the microencapsulated essential oils. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

复凝聚法制备农药微胶囊剂的研究

以壳聚糖和木质素磺酸钠为囊材,以三氟氯氰菊酯为囊芯,采用复凝聚法制备了微胶囊。考察了壳芯质量比、温度、搅拌速度、对包药率的影响,确定最佳工艺条件,并对其性能进行了研究。     

一种蓝色电泳液微胶囊的制备与表征

采用十八胺对酞青蓝BGs进行化学修饰,以Span-80为稳定剂,四氯乙烯为分散介质,制备了分散性和稳定性良好的电泳显示液.用该电泳液作囊芯,以尿素和甲醛进行界面反应形成囊壁,制备了蓝色电子墨水微胶囊,讨论了搅拌速度、酸化时间和固化条件等对微胶囊形貌与物理性质的影响.所制备微胶囊呈规则球形,表面光滑,囊壁结构致密,平均粒径为100 μm,包覆率达89%.采用红外光谱、光学显微镜和电泳实验等方法,研究微胶囊结构及电场响应,蓝色电泳液微胶囊在电场作用下具有明显可逆移动响应.     

Glycyrrhetinic Acid Liposomes Encapsulated Microcapsules from Microfluidic Electrospray for Inflammatory Wound Healing

In diabetic wound healing, M1 macrophage accumulation and elevated inflammation are prevalent issues. Intelligent delivery systems that can sustainably release antioxidizing and anti-inflammatory ingredients are expected for effective wound healing. Herein, a novel glycyrrhetinic acid (GA) liposomes encapsulated microcapsules delivery system that has desired features for inflammatory wound repair is presented. As the bacteria could break down the alginate shells, the GA liposomes could be controllably released from the microcapsules, which promotes M2 macrophage polarization and regulate their responses in the inflammatory wound microenvironment. Based on these, it is demonstrated that the GA liposomes encapsulated microcapsules delivery system exhibits an anti-inflammatory and immunomodulatory effect for diabetic wound healing in a full-thickness defect model in diabetic rats. These results indicate that the immunomodulatory capabilities of the microcapsules can be unitized for efficient wound repair, and such a delivery system is valuable for clinical wound healing applications.