Self‐Assembly‐Induced Colloidal Covalent Organic Frameworks Toward Photocatalytic H 2 Evolution: A Surfactant‐Free Concept

Covalent Organic Frameworks (COFs) are promising materials for photocatalytic applications due to their tunable optoelectronic properties. However, their rapid precipitation in solution limits their processability and functionality. In this study, the new concept of Self-Assembly-Induced Colloidal COFs SAI2COF is investigated by in situ stabilization of a donor-acceptor TtaTpa COF with a macromolecular blocking agent, i.e., Poly(2-(DiMethylAmino)Ethyl Methacrylate) (PDMAEMA), to control particle morphology, dispersion, and colloidal stability. Three synthesis strategies are explored to introduce the blocking agent at different stages of COF formation. Kinetic monitoring via UV-vis spectroscopy demonstrated that PDMAEMA slows COF growth, delaying precipitation while preserving crystallinity and light absorption properties. Morphological analyses revealed that stabilization strategies significantly influence particle surface characteristics, yielding colloidally stabilized COFs. Aqueous redispersion experiments confirmed that COFs synthesized via these strategies can be stabilized in a water medium. This approach offers an original surfactant-free pathway toward the development of stable colloidal COFs for photocatalytic hydrogen production.