P2 “Enamel”: Natural enamel and water-glass based composites – decoding structure-function relationship regarding fatigue resistance of two complementary systems

P2“牙釉质”：天然牙釉质和水玻璃基复合材料 â 解码两个互补系统的抗疲劳性的结构-功能关系

• 批准号: 535548918
• 负责人: Professorin Dr.-Ing. Claudia Fleck
• 金额: --
• 依托单位: Fachgebiet Werkstofftechnik
• 依托单位国家: 德国
• 项目类别: Research Units
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/535548918?language=en
• 关键词: P2; Enamel; Natural; enamel; water

Enamel is the hardest material in the human body and forms the outermost protection of teeth. It has a complex hierarchical structure based on 95% hydroxyapatite (HA) nanofiber crystallites bundled to rods that are oriented into different directions. A small amount of organic matrix accumulates at sites of low mineral density, e.g. between crystals and prisms. The micro- and nanoarchitecture of natural tooth enamel and the arrangement of inorganic nanocrystals in a low amount of organic matrix contribute significantly to the outstanding fatigue resistance that enables lifelong function. Nevertheless, under certain conditions, crack formation and propagation can affect and damage the natural tooth enamel. Little is known, however, about the long-time fatigue behavior of enamel. Sodium-silicate solution (“water-glass”, WG), is a versatile, inorganic material with tuneable (visco-)elastic properties. Its chemistry and the adjustable water content allow manufacturing of WG based composites by a variety of processing routes. In combination with (bio-) polymers WG can be used to process organic-inorganic model structures with varying mineral content. It is therefore an ideal precursor for nanocomposites inspired by the complex fiber-based composite structure of enamel. The aim of this project is to transfer natural enamel architecture to WG-based composite structures, from the nano- to the macro-scale, while exploiting the versatility of WG processing. We will combine 3D-printing, electrospinning and electro-writing techniques to reach versatile novel processing routes. Tailoring the interface between the polymer and inorganic phases will further be inspired by the experience from dental applications and inorganic materials. This will be an asset contributing also to the other FOR projects. By investigating fatigue behavior and resistance of natural enamel and WG-based composites we will identify structural strategies and features that contribute to fatigue resistance in a similar or different way and how this affects longevity. To understand the relative contribution of the hierarchical nano- and microstructure on the long-time fatigue resistance of enamel and of 2D and 3D WG-based composites, we will perform fatigue tests on macro-specimens in a chewing simulator, and on the micro- and nanoscale with cyclic nanoindentation in the central fatigue lab. Important facets throughout the project are water content and temperature, influencing processing and properties of the WG-based composites, as well as water content, composition of the environmental medium and temperature during specimen preparation and fatigue testing of specimens of both material groups. Thus, together with the other FOR members, we will contribute to develope reliable specimen preparation and fatigue testing procedures for biological and bio-inspired nanocomposites.

牙釉质是人体内最坚硬的物质，形成牙齿的最外层保护。它具有复杂的分层结构，基于95%的羟基磷灰石（HA）微晶，这些微晶捆绑成不同方向的棒。少量的有机基质聚集在低矿物密度的部位，例如晶体和棱柱之间。天然牙釉质的微观和纳米结构以及无机纳米晶体在少量有机基质中的排列显著有助于实现终身功能的出色抗疲劳性。然而，在某些条件下，裂纹的形成和扩展会影响和损坏天然牙釉质。然而，人们对牙釉质的长期疲劳行为知之甚少。硅酸钠溶液（“水玻璃”，WG）是一种具有可调（粘）弹性的多用途无机材料。其化学性质和可调节的含水量允许通过各种加工路线制造WG基复合材料。与（生物）聚合物结合，WG可用于处理具有不同矿物质含量的有机-无机模型结构。因此，它是纳米复合材料的理想前体，其灵感来自于搪瓷的复杂纤维基复合结构。该项目的目的是将天然搪瓷结构转移到WG基复合结构，从纳米到宏观尺度，同时利用WG加工的多功能性。我们将联合收割机3D打印、静电纺丝和电写入技术相结合，以实现多功能的新型加工路线。定制聚合物和无机相之间的界面将进一步受到牙科应用和无机材料经验的启发。这将是一项资产，也有助于其他森林项目。通过研究天然牙釉质和WG基复合材料的疲劳行为和抵抗力，我们将确定以相似或不同方式有助于抗疲劳性的结构策略和特征，以及这如何影响寿命。为了了解分层纳米和微观结构对釉质和2D和3D WG基复合材料的长期抗疲劳性的相对贡献，我们将在咀嚼模拟器中对宏观试样进行疲劳测试，并在中央疲劳实验室中使用循环纳米压痕对微观和纳米尺度进行疲劳测试。整个项目的重要方面是水含量和温度，影响WG基复合材料的加工和性能，以及水含量，环境介质的成分和样品制备过程中的温度以及两种材料组的样品的疲劳测试。因此，与其他FOR成员一起，我们将为生物和生物启发的纳米复合材料开发可靠的样品制备和疲劳测试程序做出贡献。