Li Yuxin, Zhao Jinping, Zhang Jianduo, Gong Xinyu, Zhou Jin, Zhang Ning, Su Yang
Institute of Materials Research, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, P. R. China.
School of Chemistry and Chemical Engineering, Shandong University of Technology, Zibo, P. R. China.
Nat Commun. 2025 Jun 23;16(1):5363. doi: 10.1038/s41467-025-60680-x.
Artificial stimulus-responsive membranes, particularly those responsive to different solvents, have important applications in complex and graded separation systems. Inspired by natural lipid membrane that alters mass transport behavior in response to interactions with various solvents, we report that incorporating porous graphene (PG) into graphene oxide (GO) membrane enables smart and switchable molecular sieving reversibly responsive to solvent types. The membrane shows high permeance for water and methanol, 45.52 and 13.56 L m h bar, respectively, and its molecular weight cut-off (MWCO) at ~319 g mol in water, similar to pristine GO membrane, reversibly switches to 960 g mol in methanol which is not observed in either pristine GO or graphene membrane. We accounted this switching to the change of transport pathways. In water, the GO-GO nanochannel is dominant, providing similar molecular sieving to pristine GO. In methanol, the GO-PG nanochannel becomes favorable because a strong solvent adsorption on the nanochannel surface, coupled with a weak solvent network under nanoconfinement, promotes a significant interlayer expansion, reducing the transport resistance and enabling larger, switched MWCO. This switchable sieving behavior is further demonstrated for efficient graded separation of ternary solution of solutes with various molecular weights.
人工刺激响应膜，特别是那些对不同溶剂有响应的膜，在复杂的分级分离系统中具有重要应用。受天然脂质膜在与各种溶剂相互作用时改变传质行为的启发，我们报道将多孔石墨烯（PG）掺入氧化石墨烯（GO）膜中可实现对溶剂类型可逆响应的智能且可切换的分子筛作用。该膜对水和甲醇具有高渗透率，分别为45.52和13.56 L m h bar，其在水中的截留分子量（MWCO）约为319 g mol，与原始GO膜相似，在甲醇中可逆地切换至960 g mol，这在原始GO膜或石墨烯膜中均未观察到。我们将这种切换归因于传输途径的变化。在水中，GO - GO纳米通道占主导，提供与原始GO相似的分子筛作用。在甲醇中，GO - PG纳米通道变得更有利，因为纳米通道表面的强溶剂吸附，加上纳米限域下的弱溶剂网络，促进了显著的层间膨胀，降低了传输阻力并实现了更大的、切换后的MWCO。这种可切换的筛分行为在对具有各种分子量的溶质的三元溶液进行高效分级分离中得到了进一步证明。
