Xu Yongjian, Gao Minlan, Zhang Yongqi, Ning Lulu, Zhao Deqing, Ni Yonghao
College of Light Industry and Energy, Shaanxi University of Science & Technology, Xi'an, Shaanxi 710021, China.
College of Bioengineering, Sichuan University of Science and Engineering, YiBin 644000, China.
ACS Nano. 2022 Jun 28;16(6):8928-8938. doi: 10.1021/acsnano.1c11167. Epub 2022 Jun 10.
Cellulose nanomaterials, such as cellulose nanocrystals (CNCs), have received enormous attention in various material research fields due to their unique properties and green/sustainable nature, among other qualities. Herein, we report hollow-type annular cellulose nanocrystals (HTA-CNCs), which are generated by following a high-intensity ultrasonic treatment. The advanced aberration-corrected transmission electron microscopy results reveal that HTA-CNCs exhibit ring structures with a typical diameter of 10.0-30.0 nm, a width of 3.0-4.0 nm, and a thickness of 2.0-5.0 nm, similar to those of elementary crystallites. The X-ray diffraction measurements show that the as-prepared HTA-CNCs maintain the cellulose I structure. The changes in structure and hydrogen-bonding characteristics of HTA-CNCs are further determined based on the FT-IR results after deconvolution fitting, showing that three types of hydrogen bonds decrease and the content of free OH increases in HTA-CNCs compared with those in the original CNCs. Furthermore, molecular dynamics simulation is carried out to support the experimental study. The formation of HTA-CNCs might be attributed to the structural change and entropy increase. The hollow-type annular CNCs may have broad value-added applications as cellulose nanomaterials in different fields.
纤维素纳米材料，如纤维素纳米晶体（CNCs），因其独特性能以及绿色/可持续特性等诸多品质，在各种材料研究领域受到了广泛关注。在此，我们报道了中空型环形纤维素纳米晶体（HTA-CNCs），其是通过高强度超声处理制备而成的。先进的像差校正透射电子显微镜结果表明，HTA-CNCs呈现出典型直径为10.0 - 30.0 nm、宽度为3.0 - 4.0 nm以及厚度为2.0 - 5.0 nm的环形结构，与初级微晶的结构相似。X射线衍射测量结果显示，所制备的HTA-CNCs保持纤维素I结构。基于去卷积拟合后的傅里叶变换红外光谱结果，进一步确定了HTA-CNCs的结构和氢键特性变化，结果表明与原始CNCs相比，HTA-CNCs中三种类型的氢键减少，游离OH的含量增加。此外，进行了分子动力学模拟以支持实验研究。HTA-CNCs的形成可能归因于结构变化和熵增加。作为纤维素纳米材料，中空型环形CNCs在不同领域可能具有广泛的增值应用。
