Gel‐Locked Lamellar Membranes: Overcoming the Limitations of Permeance, Selectivity, and Stability

Nanosheets‐stacked lamellar membranes with unique 2D nanochannels are promising platform to achieve ultrafast molecule sieving over conventional membranes in numerous separation applications. Despite significant successes in material design and structure optimization, existing lamellar membranes remain challenging to achieve boosted permeance, selectivity, and stability simultaneously, owing to their limited nanochannel chemistry and unstable nanochannel architecture. Herein, a new class of gel‐locked lamellar membranes (GLLMs) that feature versatile gel‐decorated nanochannel chemistry and gel‐crosslinked lamellar nanochannel architecture are discovered by an original photothermal‐triggered confined gelation (PTCG) approach. In the PTCG, the photothermal‐enabled localized heating from nanosheets is leveraged to trigger rapid and efficient generation of free radicals in their vicinity, allowing for precisely confining polymerization and gelation into lamellar nanochannels. With this method, a series of GLLMs are constructed by easily devising functional monomers and nanosheets and exhibit ultrastable nanochannel architecture with antiswelling ability in many harsh conditions. It is demonstrated that the GLLMs with customized gel‐decorated nanochannels showcase boosted permeance and selectivity over conventional lamellar membranes in many separation scenarios such as isotopic separation, optical resolution, organic solvent nanofiltration, and CO2/CH4 separation. The findings represent a paradigm shift in exploiting a family of advanced lamellar membranes with broader applications.