Sarker Pranab, Lu Tieyi, Liu Di, Wu Guangyao, Chen Hanning, Jahan Sajib Md Symon, Jiang Shaoyi, Chen Zhan, Wei Tao
Department of Chemical Engineering, Howard University Washington D.C. USA
Department of Chemistry, University of Michigan Ann Arbor Michigan USA
Chem Sci. 2023 Jun 6;14(27):7500-7511. doi: 10.1039/d3sc01977b. eCollection 2023 Jul 12.
Zwitterionic materials have emerged as highly effective ultralow fouling materials for many applications, however the underlying mechanism of fouling resistance remains unclear. Using molecular dynamics simulations and surface-sensitive sum frequency generation vibrational spectroscopy, we studied the hydration behaviors of zwitterionic materials, including trimethylamine--oxide (TMAO) and carboxybetaines of different charge-separation distances, to understand their fouling-resistant mechanism and provide a design principle for improved performance. Our study reveals that the interplay among hydrogen bonding, net charge, and dipole moment is crucial to the fouling-resistant capabilities of zwitterionic materials. Shortening of the zwitterionic spacing strengthens hydrogen bonding with water against biomolecule attachment due to the increased electrostatic and induction interactions, charge transfer, and improved structural stability. Moreover, the shortened charge separation reduces the dipole moment of zwitterionic materials with an intrinsic near-neutral net charge, decreasing their electrostatic and dipole-dipole interactions with biofoulers, and increasing their resistance to fouling. Compared to carboxybetaine compounds, TMAO has the shortest zwitterionic spacing and exhibits the strongest hydrogen bonding, the smallest net charge, and the minimum dipole moment, making it an excellent nonfouling material.
两性离子材料已成为许多应用中高效的超抗污材料，然而其抗污的潜在机制仍不清楚。我们使用分子动力学模拟和表面敏感的和频振动光谱，研究了两性离子材料的水合行为，包括三甲胺氧化物（TMAO）和不同电荷分离距离的羧酸甜菜碱，以了解它们的抗污机制，并为性能改进提供设计原则。我们的研究表明，氢键、净电荷和偶极矩之间的相互作用对两性离子材料的抗污能力至关重要。两性离子间距的缩短增强了与水的氢键作用，以抵抗生物分子的附着，这是由于静电和诱导相互作用、电荷转移以及结构稳定性的提高。此外，缩短的电荷分离降低了具有固有近中性净电荷的两性离子材料的偶极矩，减少了它们与生物污垢剂的静电和偶极-偶极相互作用，并提高了它们的抗污能力。与羧酸甜菜碱化合物相比，TMAO具有最短的两性离子间距，表现出最强的氢键作用、最小的净电荷和最小的偶极矩，使其成为一种优异的非污材料。
