Cellulose nanocrystals (CNCs) are bio-based building blocks for sustainable advanced materials with prospective applications in polymer composites, emulsions, electronics, sensors, and biomedical devices. However, their high surface area-to-volume ratio promotes agglomeration, which restrains their performance in size-driven applications, thereby hindering commercial CNC utilization. In this regard, ultrasonication is commonly applied to disperse CNCs in colloidal suspensions; however, ultrasonication methodology is not yet standardized and knowledge of the effects of ultrasound treatments on CNC size distribution is scarce. The major goals of this study were attributed to targeted breakage of CNC agglomerates and clusters by ultrasound. The evolution of particle size distribution and potential de-sulfation by ultrasonication as well as the long-term stability of ultrasonicated CNC suspensions were investigated. Colloidal suspensions of sulfated CNCs were isolated from cotton α-cellulose. Effects of ultrasonication on particle size distribution were determined by asymmetrical flow field-flow fractionation (AF4) coupled with on-line multi-angle light scattering and ultraviolet spectroscopy. These results were complemented with off-line dynamic light scattering. High ultrasound energy densities facilitated cumulative dispersion of CNC clusters. Consequently, the mean rod length decreased logarithmically from 178.1 nm at an ultrasound energy input of 2 kJ g⁻¹ CNC to 141.7 nm (− 20%) at 40 kJ g⁻¹ CNC. Likewise, the hydrodynamic diameter of the particle collective decreased logarithmically from 94.5 to 73.5 nm (− 22%) in the same processing window. While the rod length, below which 95 wt% of the CNCs were found, decreased from 306.5 to 231.8 nm (− 24%) from 2 to 40 kJ g⁻¹ CNC, the shape factor of the main particle fraction ranged from 1.0 to 1.1, which indicated a decreasing number of dimers and clusters in the particle collective. In summary, progressing ultrasonication caused a shift of the particle length distribution to shorter particle lengths and simultaneously induced narrowing of the distribution. The suspension’s electrical conductivity concurrently increased, which has been attributed to faster diffusion of smaller particles and exposure of previously obscured surface charges. Colloidal stability, investigated through electrical AF4 and electrophoretic light scattering, was not affected by ultrasonication and, therefore, indicates no de-sulfation by the applied ultrasound treatment. Occurrence of minor CNC agglomeration at low ultrasound energy densities over the course of 6 months suggest the effect was not unmitigatedly permanent.

纤维素纳米晶体 (CNC) 是可持续先进材料的生物基构建块，在聚合物复合材料、乳液、电子产品、传感器和生物医学设备中具有前瞻性应用。然而，它们的高表面积与体积比促进了团聚，这限制了它们在尺寸驱动应用中的性能，从而阻碍了 CNC 的商业应用。在这方面，超声波处理通常用于在胶体悬浮液中分散 CNCs；然而，超声波处理方法尚未标准化，并且关于超声波处理对 CNC 尺寸分布的影响的知识很少。这项研究的主要目标归因于通过超声有针对性地破坏 CNC 附聚物和簇。研究了粒径分布的演变和超声处理的潜在脱硫作用以及超声处理的 CNC 悬浮液的长期稳定性。从棉花 α-纤维素中分离出硫酸化 CNCs 的胶体悬浮液。通过不对称流场-流动分级 (AF4) 结合在线多角度光散射和紫外光谱测定超声处理对粒度分布的影响。这些结果与离线动态光散射相辅相成。高超声能量密度促进了 CNC 簇的累积分散。因此，当超声能量输入为 2 kJ g 时，平均杆长从 178.1 nm 对数减少 从棉花 α-纤维素中分离出硫酸化 CNCs 的胶体悬浮液。通过不对称流场-流动分级 (AF4) 结合在线多角度光散射和紫外光谱测定超声处理对粒度分布的影响。这些结果与离线动态光散射相辅相成。高超声能量密度促进了 CNC 簇的累积分散。因此，当超声能量输入为 2 kJ g 时，平均杆长从 178.1 nm 对数减少 从棉花 α-纤维素中分离出硫酸化 CNCs 的胶体悬浮液。通过不对称流场-流动分级 (AF4) 结合在线多角度光散射和紫外光谱测定超声处理对粒度分布的影响。这些结果与离线动态光散射相辅相成。高超声能量密度促进了 CNC 簇的累积分散。因此，当超声能量输入为 2 kJ g 时，平均杆长从 178.1 nm 对数减少 高超声能量密度促进了 CNC 簇的累积分散。因此，当超声能量输入为 2 kJ g 时，平均杆长从 178.1 nm 对数减少 高超声能量密度促进了 CNC 簇的累积分散。因此，当超声能量输入为 2 kJ g 时，平均杆长从 178.1 nm 对数减少^-1 CNC 至 141.7 nm (- 20%) 在 40 kJ g ^-1 CNC。同样，在相同的处理窗口中，粒子集合的流体动力学直径从 94.5 纳米到 73.5 纳米（- 22%）呈对数下降。而杆长（低于 95 wt% 的 CNCs 被发现）从 306.5 nm (- 24%) 从 2 kJ g ^{-1 减少}到 40 kJ g ^-1CNC，主要粒子分数的形状因子范围从 1.0 到 1.1，这表明粒子集合中二聚体和簇的数量减少。总之，进行超声处理导致颗粒长度分布向更短的颗粒长度移动，同时导致分布变窄。悬浮液的电导率同时增加，这归因于较小颗粒的更快扩散和先前模糊的表面电荷的暴露。通过电 AF4 和电泳光散射研究的胶体稳定性不受超声波处理的影响，因此表明应用的超声波处理没有脱硫。