Topo-chemical characterisation of dissolution processes of phosphate glasses

磷酸盐玻璃可以溶解在水溶液中，这对某些应用(如控制释放)来说是一个巨大的优势，但对其他应用(如激光眼镜或光学滤光片)来说却是一个明显的缺点。到目前为止，根据我们目前的知识，定制和控制玻璃溶解只能通过现象学的方法来实现。对溶解机理的更好理解可能会为优化玻璃的结构设计铺平道路，这些结构设计具有定制的溶解度或改善的化学稳定性。在这里，31P溶液核磁共振(核磁共振)波谱将被用来表征溶解过程中形成的磷酸盐碎片，无论是使用原位还是非原位方法。这将使我们深入了解溶液中发生的网络溶解、裂解和水解。修正的基于拓扑学的计算考虑了场强、堆积和中程(立体)效应，已成功地用于描述磷酸盐玻璃的力学性质。这些基于结构的模型将在这里扩展，以允许精确的定量预测和溶解过程的优化。本研究的目的是将实验研究与拓扑学和结构化学模型相结合。这将深入了解磷酸盐玻璃的溶解机理，并随后通过优化玻璃成分和控制溶解过程中的化学参数，开发新的控制和调整玻璃溶解度的策略。

Phosphate glasses can dissolve in aqueous solutions, which is a great advantage for some applications (e.g. controlled release), but a pronounced drawback for others (e.g. laser glasses or optical filters). Tailoring and controlling glass dissolution has so far, based on our current knowledge, been achieved by phenomenological approaches only. An improved understanding of the dissolution mechanism may pave the way towards the structural design of optimised glasses of tailored solubility or improved chemical stability. Here, 31P solution nuclear magnetic resonance (NMR) spectroscopy will be used to characterise phosphate fragments formed during dissolution, either using in situ or ex situ approaches. This will give insight into network dissolution and fragmentation as well as hydrolysis occurring in solution. Modified topology-based calculations, which account for field strength, packing and medium-range (sterical) effects, have been used successfully to describe the mechanical properties of phosphate glasses. These structure-based models will be extended here to allow for precise quantitative prediction and optimisation of the dissolution process. The aim of this study is the combination of experimental investigations with topological and structure-chemical models. This will give insight into the mechanisms of phosphate glass dissolution and, subsequently, allow for the development of new strategies for controlling and tailoring glass solubility, through optimised glass compositions on the one hand and control of chemical parameters during dissolution on the other hand.