Some of the most popular cellulose derivatives exhibit charged functional groups, either cationic (generally, quaternary ammonium moieties) or anionic (most typically, carboxylate groups). Noticeably, the second most successful cellulosic derivative in the world, in terms of market share, is the salt of a negatively charged polymer: sodium carboxymethyl cellulose. However, many of the applications that have long been proposed by researchers have never proven feasible on a large scale. In light of this, the present review critically discusses the current and potential applications of anionic and cationic cellulose derivatives: (i) coagulation-flocculation or direct flocculation processes, for which the limited molecular weight of cellulose derivatives is a key limitation; (ii) thickening and rheology modification in general, where polymer-water interactions play a major role; (iii) stabilization of colloids or emulsions, in such way that the repulsive electrostatic forces prevent aggregation unlike coagulation-flocculation; (iv) adsorption of cations by anionic cellulose, of anions by cationic cellulose, and adsorption mediated by other mechanisms; (v) encapsulation of bioactive compounds for drug delivery or other purposes; (vi) filtration by means of cellulose-based membranes, and (vii) production of antimicrobial materials by exploiting the interactions between cationic cellulose and the phospholipid bilayer of microorganisms. We highlight the recent trends and, closely related to them, the knowledge gaps in the literature on anionic and cationic derivatives. For instance, the survey remarks on the increasing popularity of anionic or cationic nanocellulose (generally, as nanofibers or nanocrystals), progressively outweighing both conventional fibers and soluble derivatives.

一些最流行的纤维素衍生物表现出带电的官能团，阳离子（通常是季铵部分）或阴离子（最典型的是羧酸盐基团）。值得注意的是，就市场份额而言，世界上第二大最成功的纤维素衍生物是带负电荷的聚合物的盐：羧甲基纤维素钠。然而，研究人员长期以来提出的许多应用从未被大规模证明是可行的。鉴于此，本综述批判性地讨论了阴离子和阳离子纤维素衍生物的当前和潜在应用：（i）凝结-絮凝或直接絮凝过程，纤维素衍生物的有限分子量是关键限制；(ii) 一般的增稠和流变改性，聚合物与水的相互作用起主要作用的地方；(iii) 胶体或乳液的稳定化，与凝结-絮凝不同，静电排斥力可防止聚集；(iv) 阴离子纤维素吸附阳离子，阳离子纤维素吸附阴离子，以及其他机制介导的吸附；(v) 用于药物输送或其他目的的生物活性化合物的封装；(vi) 通过基于纤维素的膜进行过滤，以及 (vii) 通过利用阳离子纤维素与微生物磷脂双层之间的相互作用来生产抗菌材料。我们强调了最近的趋势，以及与它们密切相关的阴离子和阳离子衍生物文献中的知识缺口。例如，