Many efforts have been made to isolate native nanocrystals from raw materials in the last two decades, such as cellulose nanocrystals (CNCs), but existing methods still suffer from low yields, complicated synthesis processes, and nonuniform sizes of obtained CNCs. This study concerns a facile, self‐terminating, and efficient method for the formation of uniform CNCs in high yields during the periodate oxidation process within Pickering emulsions. A biphasic system containing hexane with dissolved hexylamine and an aqueous solution of sodium periodate (NaIO₄) was used as the reaction medium. Regulated by hexylamine, owing to its limited solubility in water, the pH value of the aqueous phase was enhanced to around 9.8, leading to the precipitation of sodium orthoperiodate (Na₂H₃IO₆) nanoplates and thus the formation of the initial Pickering emulsions. During the gradual formation of cellulose nanofibers and then CNCs, CNCs were attracted to stabilize the interface of the Pickering emulsions, which prevented further decomposition of CNCs by the oxidizing agent in aqueous suspensions. Thus, this isolation strategy secured the efficient separation of CNCs based on their own particular amphiphilic properties and achieved a high yield of up to 56 wt %.

中文翻译：

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在Pickering乳液中通过高碘酸氧化有效，自终止地分离纤维素纳米晶体

在过去的二十年中，已经进行了许多努力来从原材料中分离天然纳米晶体，例如纤维素纳米晶体（CNC），但是现有方法仍然存在产量低，合成工艺复杂以及所获得的CNC晶体尺寸不均匀的问题。这项研究涉及一种在Pickering乳液中的高碘酸盐氧化过程中以高收率形成均匀CNC的简便，自终止且有效的方法。将包含己烷与溶解的己胺和高碘酸钠（NaIO ₄）水溶液的双相系统用作反应介质。受己胺调节，由于其在水中的溶解度有限，水相的pH值提高到9.8左右，导致原高铁酸钠（Na ₂ H₃ IO ₆）纳米板，从而形成了最初的Pickering乳液。在逐渐形成纤维素纳米纤维然后形成CNC的过程中，吸引CNC来稳定Pickering乳液的界面，这防止了CNC在水溶液悬浮液中被氧化剂进一步分解。因此，这种分离策略确保了基于CNCs自身特殊的两亲特性的有效分离，并实现了高达56 wt％的高收率。