Yang Mengmei, Zuo Songlin, Hu Xin
College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, China.
Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, Nanjing Forestry University, Nanjing, 210037, China.
Small. 2023 Nov;19(44):e2303310. doi: 10.1002/smll.202303310. Epub 2023 Jul 7.
The stability and transformation of nanomaterial aqueous suspensions are essential for their applications. Preparation of high-concentration carbon nanomaterials suspensions remains challenging due to their nonpolar nature. Herein, 200 mg mL carbon nanomaterial aqueous suspensions are achieved by using graphite-like crystalline nanosheets (GCNs) with high hydrophilicity. Furthermore, these high-concentration GCN aqueous suspensions spontaneously transform into gels when induced by mono-, di-, and trivalent metal salt electrolytes at room temperature. Theoretical calculation of potential energy by DLVO theory reveals that the gelatinized GCNs is a new and metastable state between two usual forms of solution and coagulation. It is shown that the gelation of GCNs is due to the preferential orientation of nanosheets in an edge-edge arrangement, which differs from the case of solution and coagulation. High-temperature treatment of GCN gels produces metal/carbon materials with pore structures. This work provides a promising opportunity to create various metal/carbon functional materials.
纳米材料水悬浮液的稳定性和转变对其应用至关重要。由于其非极性性质，制备高浓度碳纳米材料悬浮液仍然具有挑战性。在此，通过使用具有高亲水性的类石墨晶体纳米片（GCNs）实现了200 mg/mL的碳纳米材料水悬浮液。此外，这些高浓度的GCN水悬浮液在室温下受到一价、二价和三价金属盐电解质诱导时会自发转变为凝胶。通过DLVO理论对势能进行理论计算表明，凝胶化的GCNs是介于溶液和凝聚两种常见形式之间的一种新的亚稳态。结果表明，GCNs的凝胶化是由于纳米片以边-边排列的优先取向，这与溶液和凝聚的情况不同。对GCN凝胶进行高温处理可产生具有孔结构的金属/碳材料。这项工作为制备各种金属/碳功能材料提供了一个有前景的机会。
