Optical Fibre Technology Centre and School of Molecular and Microbial Biosciences, University of Sydney, New South Wales 2006, Australia, and School of Physical and Chemical Sciences, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia.
ACS Appl Mater Interfaces. 2009 Jan;1(1):197-203. doi: 10.1021/am800059c.
Nuclear magnetic resonance was used to probe the distribution of water and ionic species in a microstructured poly(methyl methacrylate) (PMMA) polymer optical fiber (MPOF), with a plan to assess the suitability of these fibers for aqueous chemosensing. The NMR spectra and the measurements of proton spin relaxation in hydrated fibers demonstrated the presence of two distinct pools of water: water residing in the microstructure channels and the hydration water residing in the polymer matrix of the fiber. No facile chemical exchange between these two pools was present. The NMR peaks of the two pools of water were separated by 1.53 ppm. Relaxation measurements of the fiber samples doped with aqueous copper sulfate showed that charged ions freely entered the microstructure channels but were completely excluded from the polymer matrix of the fiber. Measurements of the apparent diffusion coefficient of water along the axial direction of the fiber showed that water molecules moved unimpeded along the channels. This is the first reported magnetic-resonance study of microstructured optical fibers. The findings suggest that microstructured PMMA fibers are compatible with ionic aqueous solutions and could provide a robust and durable platform for chemical-sensing applications.
核磁共振被用于探测微结构聚甲基丙烯酸甲酯（PMMA）聚合物光纤（MPOF）中水分子和离子种类的分布，旨在评估这些光纤在水相化学传感方面的适用性。水合纤维的核磁共振谱和质子自旋弛豫测量表明，存在两种不同的水分子池：一种是位于微结构通道中的水分子，另一种是位于纤维聚合物基质中的水合水分子。这两种水分子池之间没有容易发生的化学交换。这两个水分子池的 NMR 峰分离为 1.53ppm。对掺杂硫酸铜水溶液的纤维样品进行弛豫测量表明，带电荷的离子可以自由进入微结构通道，但完全被纤维聚合物基质排斥。对纤维轴向方向上水分子的表观扩散系数的测量表明，水分子可以沿着通道无障碍地移动。这是首次对微结构光纤进行磁共振研究。研究结果表明，微结构 PMMA 光纤与离子型水溶液兼容，可为化学传感应用提供一种坚固耐用的平台。
