Observations on Spatial Specificity in the Modification of Porous Graphene Layers

TL;DR

Researchers developed a way to selectively modify the edges of pores in graphene sheets, which could lead to advanced membranes for water filtration and other applications.

Contribution

The study demonstrates spatially selective functionalization of graphene pore edges using SIPGP, enabling tunable and targeted modification.

Findings

Polymer chains are selectively grafted along the pore edges of graphene using SIPGP.

The spatial selectivity is confirmed by polymer rims observed in atomic force microscopy.

Pore dimensions and polymer rim height can be tuned by adjusting reaction conditions.

Abstract

Self‐initiated photografting and photopolymerization (SIPGP) is a simple one‐step polymerization process that can yield dense polymer layers on various surfaces, including pristine graphene. This process, however, has so far not been managed to be site selective. Herein, SIPGP is used to selectively functionalize the edges of pores in chemical vapor‐deposited porous graphene sheets. The pore edges formed during the graphene fabrication serve as directing reactive sites for the functionalization process. By polymerizing styrene monomers from the pore edges using a radical‐mediated process, polymer chains are preferentially grafted along and from the pore edges of the graphene. The spatial selectivity of the process is unambiguously demonstrated by the presence of a polymer rim around the pores in the atomic force microscopy data. The height of these polymer rims and the pore dimensions are measured, demonstrating the tunability of these characteristics by changing the reaction conditions (varying polymerization time from 0 to 24 h). The precise selectivity and controllability of the SIPGP process for the pore edges are potentially interesting for using porous graphene as functional membranes in different technological applications such as Per‐ and Polyfluoroalkyl substances (PFAs) ‐free waterproof membrane or state‐of‐the‐art membranes for water desalination.

Exploiting the reactive defects at the pore edges, the possibility of regional‐specific functionalization is conclusively shown. This approach is simple, scalable, and facilitates the reinforcement of porous graphene. This targeted modification along the pore edges can lead to specific tailoring of the pore properties, offering the potential to fabricate the “ultimate graphene membrane.”© 2025 WILEY‐VCH GmbH

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