Lewis Lev, Hatzikiriakos Savvas G, Hamad Wadood Y, MacLachlan Mark J
Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada.
Chemical and Biological Engineering, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
ACS Macro Lett. 2019 May 21;8(5):486-491. doi: 10.1021/acsmacrolett.9b00140. Epub 2019 Apr 8.
Gels are attractive for applications in drug delivery, tissue engineering, and 3D printing. Here, physical colloidal gels were prepared by freeze-thaw (FT) cycling of cellulose nanocrystal (CNC) suspensions. The aggregation of CNCs was driven by the physical confinement of CNCs between growing ice crystal domains. FT cycling was employed to form larger aggregates of CNCs without changing the surface chemistry or ionic strength of the suspensions. Gelation of CNC suspensions by FT cycling was demonstrated in water and other polar solvents. The mechanical and structural properties of the gels were investigated using rheometry, electron microscopy, X-ray diffraction, and dynamic light scattering. We found that the rheology could be tuned by varying the freezing time, the number of FT cycles, and concentration of CNCs in suspension.
凝胶在药物递送、组织工程和3D打印应用中具有吸引力。在此，通过对纤维素纳米晶体（CNC）悬浮液进行冻融（FT）循环制备了物理胶体凝胶。CNC的聚集是由生长的冰晶域之间CNC的物理限制驱动的。采用FT循环形成更大的CNC聚集体，而不改变悬浮液的表面化学性质或离子强度。通过FT循环实现的CNC悬浮液的凝胶化在水和其他极性溶剂中得到了证明。使用流变学、电子显微镜、X射线衍射和动态光散射研究了凝胶的力学和结构性质。我们发现，流变学可以通过改变冷冻时间、FT循环次数和悬浮液中CNC的浓度来调节。
