Biocompatible and Smart Composites from Cellulose, Wool, and Phase-Change Materials Encapsulated in Natural Sporopollenin Microcapsules
Biocompatible and Smart Composites from Cellulose, Wool, and Phase-Change Materials Encapsulated in Natural Sporopollenin Microcapsules
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DOI：
10.1021/acssuschemeng.0c02001
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发表时间：
2020-07-13
影响因子：
8.4
通讯作者：
Tran, Chieu D.
中科院分区：
文献类型：
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作者：
Becherini, Stefano;Mitmoen, Mark;Tran, Chieu D.
对天然花粉粒进行清洗，去除所有胞外和胞内的物质，得到孢子花粉外胚囊（SECs）。sec是一种空的微胶囊，具有直径约为200纳米的孔洞网络，它们保持完整。各种物质，包括相变材料（PCMs），如正十八烷（C18），正二十烷（C20， EIS），正十二烷（C22），或它们的混合物（C18 + C22），可以被封装到sec的空腔中。[EIS（或PCMs）@SEC]包封效率至少为76%。sec是健壮且非常稳定的。它们在相变期间保护封装的EIS，因此它们保留了相变特性，并保护它们免受腐蚀环境和高温的影响。因此，[EIS@SEC]可以加入纤维素（CEL）和角蛋白（KER，来自羊毛）复合材料中，使用简单的离子液体丁基甲基咪唑氯[BMIM+Cl-]作为唯一溶剂合成[CEL + KER + EIS@SEC]复合材料。[CEL + KER + EIS@SEC]复合材料中的EIS的行为与单独的EIS相似。加热时熔化，冷却时结晶。这些相变产生的能量使[CEL + KER + EIS@SEC]复合材料像其他pcm一样，通过释放能量来加热周围环境，相反，通过吸收能量来加热周围环境，从而冷却周围环境。[CEL + KER + EIS@SEC]复合材料的潜热储存和释放效率估计约为80%。经过200次加热-熔化循环后，[CEL + KER + EIS@SEC]复合材料的DSC曲线保持不变。这表明sec实际上完全有效地保留了封装的EIS并保护它不泄漏。[CEL + KER + EIS@SEC]复合材料坚固耐用，具有较强的机械性能，并具有抗菌活性。这使得它们优于目前可用的其他微封装pcm。此外，复合材料具有可持续性和生物相容性，因为它们由天然丰富的材料（纤维素、羊毛、天然花粉粒和蜡）合成，采用绿色可回收的合成方法。更重要的是，事实是，不仅单个PCM（如EIS），而且两种不同PCM（如（C22 + C18）的混合物）的混合物可以同时封装到SEC中。这些功能使[CEL + KER + EIS@SEC]复合材料非常适合作为高性能材料，用于治疗感染烧伤伤口的敷料，服装的智能纺织品，智能建筑材料和任何给定温度下的能量存储。
Natural pollen grains were cleaned to remove all external and internal cytoplastic materials to produce sporopollenin exine capsules (SECs). SECs are empty microcapsules with extensive networks of holes that are similar to 200 nm in diameter, which remain intact. Various substances including phase-change materials (PCMs) such as n-octadecane (C18), n-eicosane (C20, EIS), n-docosane (C22), or a mixture of them (C18 + C22) can be encapsulated into the cavity of SECs. [EIS (or PCMs)@SEC] was obtained with an encapsulation efficiency of at least 76 wt %. SECs are robust and very stable. They protect encapsulated EIS during phase transitions, so they retain their phase change property and guard them against corrosive environments and elevated temperatures. [EIS@SEC] can therefore be incorporated into cellulose (CEL) and keratin (KER, from wool) composites using butylmethylimmidazolium chloride [BMIM+Cl-], a simple ionic liquid, as a sole solvent to synthesize [CEL + KER + EIS@SEC] composites. EIS in the [CEL + KER + EIS@SEC] composites behaves similarly to EIS alone. It will melt when heated and crystallize when cooled. Energy resulting from these phase transitions allows [CEL + KER + EIS@SEC] composites, like other PCMs, to warm their surroundings by releasing energy and, conversely, to cool their surroundings as they heat up by absorbing energy. The latent heat storage and release efficiency of the [CEL + KER + EIS@SEC] composites is estimated to be about 80%. After going through the heating-melting cycle 200 times, the DSC curves of the [CEL + KER + EIS@SEC] composites remained the same. This indicates that SECs are in fact fully and effectively retaining the encapsulated EIS and protecting it from leaking out. The [CEL + KER + EIS@SEC] composites are robust, have strong mechanical properties, and possess antibacterial activity. This makes them superior to other microencapsulated PCMs that are currently available. Furthermore, the composites are sustainable and biocompatible as they are synthesized from naturally abundant materials (cellulose, wool, natural pollen grains, and wax) using a green and recyclable synthesis. More importantly, the fact is that not only individual PCM such as EIS but also a mixture of two different PCMs such as a mixture of (C22 + C18) can be simultaneously encapsulated into the SEC. These features enable the [CEL + KER + EIS@SEC] composites to be uniquely suited as high-performance materials for such uses as dressings to treat infected burn wounds, smart textiles for clothing, smart building materials, and energy storage at any given temperature.