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 ∼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.

中文翻译：

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天然孢粉微胶囊中的纤维素，羊毛和相变材料的生物相容性和智能复合材料

清洁天然花粉粒以去除所有外部和内部细胞增生物质，以产生孢粉素外膜胶囊（SEC）。SEC是空的微囊，带有直径约200 nm的完整的孔洞网络，这些孔洞保持完整。各种物质，包括相变材料（PCM），例如正十八烷（C18），正二十烷（C20，EIS），n-二十二烷（C22）或它们的混合物（C18 + C22）可以封装到SEC腔中。以至少76wt％的包封效率获得了[EIS（或PCM）@SEC]。SEC既强大又非常稳定。它们在相变过程中保护封装的EIS，因此保留了相变特性，并防止腐蚀环境和高温。因此，可以使用氯化丁基甲基咪唑鎓盐[BMIM ⁺ Cl- ]将[EIS @ SEC]掺入纤维素（CEL）和角蛋白（羊毛的KER）复合材料中^。]，一种简单的离子液体，是合成[CEL + KER + EIS @ SEC]复合材料的唯一溶剂。[CEL + KER + EIS @ SEC]复合材料中的EIS的行为类似于单独的EIS。加热时会熔化，冷却时会结晶。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的环境，相反，当它们通过吸收能量而变热时，则可以冷却周围的环境。[CEL + KER + EIS @ SEC]复合材料的潜热存储和释放效率估计约为80％。经过200次加热熔融循环后，[CEL + KER + EIS @ SEC]复合材料的DSC曲线保持不变。这表明SEC实际上可以完全有效地保留封装的EIS并防止其泄漏。[CEL + KER + EIS @ SEC]复合材料坚固耐用，具有很强的机械性能，并具有抗菌活性。这使它们优于目前可用的其他微囊PCM。此外，这种复合材料具有可持续性且具有生物相容性，因为它们是使用绿色且可回收的合成材料从天然丰富的材料（纤维素，羊毛，天然花粉粒和蜡）合成的。更重要的是，事实是，不仅单个PCM（例如EIS）而且两个不同PCM的混合物（例如（C22 + C18）的混合物）都可以同时封装到SEC中。这些功能使[CEL + KER + EIS @ SEC]复合材料特别适合用作高性能材料，例如用于治疗受感染烧伤伤口的敷料，用于服装的智能纺织品，用于智能建筑材料的材料，