原位调控细菌纤维素微凝胶孔径构建抗高表活“岛-链”动态触变性网络

In Situ Regulation of Bacterial Cellulose Microgel Pore Size for Constructing an Anti-High-Surfactant

关键词:  细菌纤维素  孔径调控  岛-链网络  流变行为  抗表面活性剂  悬浮稳定性

Key Words:Bacterial cellulose  Pore size regulation  Island-chain network  Rheological behavior  Surfactant resistance  Suspension stability

摘要:针对高浓度表面活性剂体系中功能性粒子易沉降的难题,本研究提出通过原位调控细菌纤维素微凝胶(BC-Microgel)的孔结构,构建抗表面活性剂去缔合作用的“岛-链”动态网络。通过引入碳酸钙(CaCO?)作为造孔剂,系统探究其含量(15–120 mg/100 mL)与粒径(500 nm–100 μm)对BC-Microgel孔径及纤维形貌的双向调控规律。实验表明,30 mg/100 mL CaCO?(粒径15 μm)可诱导形成平均孔径3.17 μm的均匀多孔结构,显著增强羟丙基甲基纤维素(HPMC)与微凝胶的物理缠结,使复合体系屈服应力(0.89 Pa)和触变环面积(0.58 Pa?s-1⁾较未添加碳酸钙体系提升近3倍,有效抑制表面活性剂(AEO 20 wt%)对传统悬浮剂的去缔和效应。进一步研究表明,原位添加可溶性淀粉可增宽BC纤维带(SEM验证),赋予体系高频剪切下的弹性主导特性,而原位添加壳聚糖因静电交联引发BC-Microgel局部结构不均,导致触变响应波动。悬浮实验证实,优化体系可稳定承载密度1.26 g/cm3的Fe?O?微球,且在4–55℃内保持悬浮稳定性。本研究为高表活体系中功能粒子的可控悬浮提供了基于生物基材料的设计策略,揭示了孔径-缠结协同机制对动态网络构建的关键作用。

Abstract:To address the challenge of functional particle sedimentation in high-concentration surfactant systems, this study proposes a strategy for constructing an "island-chain" dynamic network resistant to surfactant-induced dissociation by in situ regulation of the pore structure of bacterial cellulose microgel (BC-Microgel). Calcium carbonate (CaCO?) was introduced as a pore-forming agent to systematically investigate the dual regulation effects of its concentration (15–120 mg/100 mL) and particle size (500 nm–100 μm) on the pore size and fiber morphology of BC-Microgel. Experimental results demonstrated that 30 mg/100 mL CaCO? (15 μm particle size) induced the formation of a uniform porous structure with an average pore size of 3.17 μm, significantly enhancing the physical entanglement between hydroxypropyl methylcellulose (HPMC) and the microgel. This optimization increased the yield stress (0.89 Pa) and thixotropic loop area (0.58 Pa?s^-1) of the composite system by nearly threefold compared to the CaCO?-free system, effectively suppressing the de-entanglement effect of surfactants (20 wt.% AEO) on traditional suspending agents. Further studies revealed that in situ addition of soluble starch broadened BC fiber bundles (SEM-verified), endowing the system with elasticity-dominated behavior under high-frequency shear, whereas in situ addition of chitosan caused local structural heterogeneity in BC-Microgel due to electrostatic crosslinking, leading to fluctuating thixotropic responses. Suspension experiments confirmed that the optimized system stably supported Fe?O? microspheres (density: 1.26 g/cm3) with maintained suspension stability across 4–55°C. This work provides a bio-based material design strategy for controllable particle suspension in high-surfactant systems and elucidates the critical role of pore-entanglement synergy in dynamic network construction.