Surfactant Monolayer-assisted Interfacial Synthesis (SMAIS)
On-water chemistry has generated highly crystalline, functional 2D materials through surfactant-monolayer-assisted interfacial synthesis (SMAIS), such as 2D polyimides, 2D polyimines, 2D boronate ester-linked polymers, as well as quasi-2D polyaniline. In this approach, the surfactants at the air-water interface control the morphology and crystallinity of the 2D film with molecular-level precision, by tuning the surface curvature and chemical properties of water surface. Our current research works are to extend this interfacial methodologies/concepts to conjugated bond-forming chemistries (e.g., C-C coupling), which will result in fully conjugated 2D polymers (C-2DP). With this method, we can focus on the mechanisms of crystallization and film formation, structure-property relationships, as well as their performance in functional membranes, organic devices.
 Wang, Z.; Zhang, Z.; Qi, H.; Ortega-Guerrero, A.; Wang, L.; Xu, K.; Wang, M.; Park, S.; Hennersdorf, F.; Dianat, A.; Croy, A.; Komber, H.; Cuniberti, G.; Weigand, J. J.; Kaiser, U.; Dong, R.; Feng, X. On-Water Surface Synthesis of Charged Two-Dimensional Polymer Single Crystals via the Irreversible Katritzky Reaction. Nat. Synth. 2022, 1, 69-76.
 Seki, T.; Yu, X.; Zhang,P.; Yu, C.-C.; Liu, K.; Gunkel, L.; Dong, R.; Nagata, Y.; Feng, X.; Bonn, M. Real-Time Study of on-Water Chemistry: Surfactant Monolayer-Assisted Growth of a Crystalline Quasi-2D Polymer. Chem. 2021, 7, 2548-2550.
 Zhang, T.; Qi, H.; Liao, Z.; Horev, Y. D.; Panes-Ruiz, L. A.; Petkov, P. S.; Zhang, Z.; Shivhare, R.; Zhang, P.; Liu, K.; Bezugly, V.; Liu, S.; Zheng, Z.; Mannsfeld, S.; Heine, T.; Cuniberti, G.; Haick, H.; Zschech, E.; Kaiser, U.; Dong, R.; Feng, X. Engineering Crystalline Quasi-Two-Dimensional Polyaniline Thin Film with Enhanced Electrical and Chemiresistive Sensing Performances, Nat. Commun. 2019, 10, 4225.
 Liu, K.; Qi, H.; Dong, R.; Shivhare, R.; Addicoat, M.; Zhang, T.; Sahabudeen, H.; Heine, T.; Mannsfeld, S.; Kaiser, U.; Zheng, Z.; Feng, X. On-Water Surface Synthesis of Crystalline, Few-Layer Two-Dimensional Polymers Assisted by Surfactant Monolayer, Nat. Chem. 2019, 11, 994-1000.
Copper-Surface Mediated Carbon-Carbon Coupling Reaction (CSMCCR)
Very recently, the sophistication of technologies relying on organic molecules are increasing. Organic-based materials have gone from being mostly used as dyes and drugs to being integrated into complicated organic optoelectronic device, etc. Therefore, constructing materials with high-mass diffusion including particles and charges transfer is very urgent. Today, the covalent organic framework (COF) is a kind of porous crystalline polymers with well-defined periodic chemical and topologic structures, thus regarded as a suitable candidate. However, the powdery nature strongly limits the exploration for thin film devices. Methods to fabricate these films are therefore a necessary step for its utilization. The approach introduced here (Copper-Surface-Mediated Carbon-Carbon Coupling Reaction, CSMCCR) can efficiently boost carbon-carbon coupling reaction for synthesizing high-quality large-area COF films. Specifically, in this method, the copper source serves as both the substrate and the source of catalyst. In an organic base solution, the generated copper ions form a thin diffusion layer of catalytic-active species at the interface. And then the CSMCCR thus only occurs in the confined space, in which the integrity COF films are fabricated along with the completion of C-C coupling process. About the prospect of CSMCCR, we believe it can facilitate the fabrication of high-performance thin film devices and showing the potential in organic electronics.
 Yang, Y.; Schäfer, C.; Börjesson, K. Detachable All-Carbon-Linked 3D Covalent Organic Framework Films for Semiconductor/COF Heterojunctions by Continuous Flow Synthesis. Chem. 2022, 8, 2217-2227.
 Zhang, Z.; Zhang, P.; Yang, S.; Zhang, T.; Löffler, M.; Shi, H.; Lohe, M. R.; Feng, X. Oxidation Promoted Osmotic Energy Conversion in Black Phosphorus Membranes. PNAS. 2020, 117, 13959-13966.
 Zhang, T.; Hou, Y.; Dzhagan, V.; Liao, Z.; Chai, G.; Löffler, M.; Olianas, D.; Milani, A.; Xu, S.; Tommasini, M.; Zahn, D. R. T.; Zheng, Z.; Zschech, E.; Jordan, R.; Feng, X. Copper-Surface-Mediated Synthesis of Acetylenic Carbon-Rich Nanofibers for Active Metal-Free Photocathodes, Nat. Commun. 2018, 9, 1140.
 Zhang, T.; Liao, Z.; Sandonas, L. M.; Dianat, A.; Liu, X.; Xiao, P.; Amin, I.; Gutierrez, R.; Chen, T.; Zschech, E.; Cuniberti, G.; Jordan, R. Polymerization Driven Monomer Passage through Monolayer Chemical Vapour Deposition Graphene. Nat. Commun. 2018, 9, 4051.
 Dong, R.; Zhang, T.; Feng, X. Interface-Assisted Synthesis of 2D Materials: Trend and Challenges. Chem. Rew. 2018, 118, 6189-6235.
Surface-Initiated Schiff-Base-Mediated Aldol Polycondensation (SI-SBMAP)
Polymer films with high grafting density, defined composition and architecture have been synthesized by self-assembled monolayer-assisted surface-initiated polymerization methods, such as: polymer brushes, polyethylene films, metal-organic framework (MOF) films. In this approach, polymerization reactions are induced by obtaining uniform self-assembled monolayers and providing nucleation sites for reactions, resulting in in-situ growth of uniform polymer films on a variety of substrates. Our current research works are to extend this surface-initiated approach/concept to the construction of fully conjugated (C=C) covalent organic framework (COF) films, which will yield in-situ grown, thickness-controllable, continuous, and uniform high-crystallinity and fully conjugated COF films on various substrates. With this method, we can investigate for their performance in functional membranes and organic devices through further device assembly.
 Wang, K.; Yang, H.; Liao, Z; Li, S.; Hambsch, M.; Fu, G.; Mannsfeld, S. C. B.; Sun, Q.; Zhang, T. Monolayer-Assisted Surface-Initiated Schiff-Base-Mediated Aldol Polycondensation for the Synthesis of Crystalline sp2 Carbon-Conjugated Covalent Organic Framework Thin Films. J. Am. Chem. Soc. 2023, 145, 9, 5203-5210.
 Liu, L.; Yin, L.; Cheng, D.; Zhao, S.; Zang, H. Y.; Zhang, N.; Zhu, G. Surface-Mediated Construction of an Ultrathin Free-Standing Covalent Organic Framework Membrane for Efficient Proton Conduction. Angew. Chem. Int. Ed. 2021, 60, 14875-14880.
 Fan, H.; Mundstock, A.; Feldhoff, A.; Knebel, A.; Gu, J.; Meng, H.; Caro, J. Covalent Organic Framework–Covalent Organic Framework Bilayer Membranes for Highly Selective Gas Separation. J. Am. Chem. Soc. 2018, 140, 10094-10098.
 Liang, B.; Wang, H.; Shi, X.; Shen, B.; He, X.; Ghazi, Z. A.; Khan, N. A.; Sin, H.; Khattak, A. M.; Li, L.; Tang, Z. Microporous Membranes Comprising Conjugated Polymers with Rigid Backbones Enable Ultrafast Organic-Solvent Nanofiltration. Nat. Chem. 2018, 10, 961-967.
Surface-Initiated Zero-valent Metal Mediated Controlled Radical Polymerization (SI-Mt0CRP)
Surface-initiated zero-valent metal mediated controlled radical polymerization (SI-Mt0CRP) has become an effective and versatile technique for the preparation of 2D polymer brushes from vinyl monomers on planar substrates. In the SI-Mt0CRP setup, the metal(0) plate (Cu, Fe, Zn or Sn) is placed proximately to an initiator-functionalized plate, and forms a confined polymerization system which considerably simplifies the synthesis of polymer brushes with various architectures or over large areas. In comparison to classical SI-ATRP (catalyzed by metal salts), the SI-Mt0CRP demonstrates oxygen tolerance, highly controllability, good retention of chain-end functionality, and facile recyclability of the metal catalysts (i.e., metal foil/plate). These features make SI-Mt0CRP highly desirable to functionalize materials for targeted applications, ranging from the areas of chemistry and surface science to materials science, nanotechnology, and biomedical engineering.
 Wu, D.; Yin, X.; Zhao, Y.; Wang, Y.; Li, D.; Yang, F.; Wang, L.; Chen, Y.; Wang, J.; Yang, H.; Lu G.; Liu, X.; Liu, F.; Zhang, T. Tinware-Inspired Aerobic Surface-Initiated Controlled Radical Polymerization (SI-Sn0CRP) for Biocompatible Surface Engineering. ACS Macro Lett. 2023, 12, 71-76.
 Yin, X.; Wu, D.; Yang, H.; Wang, J.; Huang, R.; Zheng, T.; Sun, Q.; Chen, T.; Wang, L.; Zhang, T. Seawater-Boosting Surface-Initiated Atom Transfer Radical Polymerization for Functional Polymer Brush Engineering. ACS Macro Lett. 2022, 11, 693-698;
 Zhang, T.; Benetti, E. M.; Jordan, R. Surface-Initiated Cu(0)-Mediated CRP for the Rapid and Controlled Synthesis of Quasi-3D Structured Polymer Brushes, ACS Macro Lett. 2019, 8, 145-153.
 Che, Y.; Zhang, T.; Du, Y.; Ihsan, A.; Claudia, M.; Rainer, J. "On Water" Surface-Initiated Polymerization of Hydrophobic Monomers, Angew. Chem. Int. Ed. 2018, 57, 16380-16384.
 Zhang, T.; Du, Y.; Müller, F.; Amin, I.; Jordan, R. Surface-Initiated Cu(0) Mediated Controlled Radical Polymerization (SI-CuCRP) Using a Copper Plate, Polym. Chem. 2015, 6, 2726-2733.