Webber Thomas R, Shannon Declan P, Gordon Leo W, Nordness Oscar A, Moon Joshua D, Clément Raphaële J, Freeman Benny D, Segalman Rachel A, Hawker Craig J, Han Songi
Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA 93106-5080.
Materials Department, University of California Santa Barbara, Santa Barbara, CA 93106-5050; Materials Research Laboratory, University of California Santa Barbara, Santa Barbara, CA 93106-5121.
J Polym Sci (2020). 2025 Aug 19. doi: 10.1002/pol.20250191.
Poly(ethylene glycol) (PEG)-based materials, like PEG-diacrylate (PEGDA), are prized for their hydrophilic, inert properties, and leveraged in hydrogels and as membrane mimics. While network chemistry is often tuned for selective transport and antifouling, fundamental understanding of water dynamics at the network surface and impact on bulk transport is limited. We utilize Overhauser dynamic nuclear polarization (ODNP) to measure nanoscale water diffusivity near a tethered spin label at the water-polymer surface and compare to bulk water diffusivity from pulsed field gradient (PFG) NMR. active ester chemistry, spin labels and varied sidechain chemistries are introduced, modulating network hydrophilicity. Tuning network hydration through crosslinker content and functional groups further impacts water diffusivity. Results show rapid nanoscale water transport at the polymer surface, reflecting network volumetric water content, with further modulation by sidechain functionality. These findings demonstrate PEGDA's utility as a membrane mimic and the critical impact of network chemistry on water transport.
基于聚乙二醇（PEG）的材料，如聚乙二醇二丙烯酸酯（PEGDA），因其亲水性、惰性特性而备受青睐，并被用于水凝胶和作为膜模拟物。虽然网络化学通常针对选择性传输和抗污进行调整，但对网络表面水动力学及其对整体传输影响的基本理解仍然有限。我们利用奥弗豪泽动态核极化（ODNP）来测量水-聚合物表面连接自旋标记附近的纳米级水扩散率，并与脉冲场梯度（PFG）核磁共振测得的体相水扩散率进行比较。引入了活性酯化学、自旋标记和不同的侧链化学，调节网络亲水性。通过交联剂含量和官能团调节网络水合作用进一步影响水扩散率。结果表明，聚合物表面存在快速的纳米级水传输，反映了网络的体积含水量，并受到侧链功能的进一步调节。这些发现证明了PEGDA作为膜模拟物的实用性以及网络化学对水传输的关键影响。
