IRDL UMR CNRS 6027, Université de Bretagne Occidentale, UFR Sciences et Techniques, 6, Avenue Victor Le Gorgeu CS 93837, 29238 Brest Cedex 3, France.
IRDL UMR CNRS 6027, Université de Bretagne Sud, Centre de Recherche C. Huygens, Rue de Saint-Maudé, BP 92116 56321 Lorient Cedex, France.
Carbohydr Polym. 2019 May 1;211:315-321. doi: 10.1016/j.carbpol.2019.01.099. Epub 2019 Feb 10.
The structure and rheology of TEMPO-oxidized cellulose nanofibrils (CNF) suspensions and hydrogels, used as precursors in the elaboration of bio-based aerogels for thermal insulation applications, were studied as a function of CNF volume fraction and ionic strength. The CNF geometry and rigidity were evaluated using AFM observations. Viscometric measurements, performed at very low CNF concentrations, highlighted the prominent role played by electroviscous effects, which can be modulated by ionic strength. Oscillatory measurements on semi-dilute CNF suspensions revealed the formation of a three-dimensional hydrogel network above a percolation fraction, which was shown to depend on the ionic strength. The rheological properties of CNF hydrogels were shown to depend on CNF fraction and ionic strength. In deionized water, the existence of two different concentration regimes was discussed in terms of network structural characteristics and CNF interactions.
TEMPO 氧化纤维素纳米纤维（CNF）悬浮液和水凝胶的结构和流变特性，作为用于隔热应用的生物基气凝胶制备的前体，研究了其作为 CNF 体积分数和离子强度函数的特性。使用 AFM 观察评估了 CNF 的几何形状和刚性。在非常低的 CNF 浓度下进行的粘度测量突出了电动效应的重要作用，而电动效应可以通过离子强度来调节。半浓 CNF 悬浮液的振荡测量揭示了在超过渗透分数时形成三维水凝胶网络，并且表明该网络取决于离子强度。CNF 水凝胶的流变性能取决于 CNF 分数和离子强度。在去离子水中，根据网络结构特征和 CNF 相互作用，讨论了两个不同浓度区的存在。
