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Crystallization: The Future is Controllable

结晶：未来可控

基本信息

批准号：
EP/D070228/1
负责人：
Sharon Cooper
金额：
$ 80.44万
依托单位：
Durham University
依托单位国家：
英国
项目类别：
Fellowship
财政年份：
2006
资助国家：
英国
起止时间：
2006 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FD070228%2F1
关键词：
Crystallization Future Controllable

项目摘要

Crystallization is one of the most important processes for the preparation and production of solid materials, including pharmaceuticals and speciality products; over 70% of solids are processed and utilized in their solid forms. Despite this prominence, the crystallization area is arguably one in which the gap between potential and realised goals is widest. Biominerals, such as bones, shells and teeth, exhibit far superior properties than their synthetic counterparts, and yet it should be possible to improve on nature's design strategies since we are not constrained to processing at ambient temperatures and pressures. Substantial improvements in this area are urgently required for the production of crystals with well-defined size, shape and structure that are so necessary for emerging nanotechnologies. Improvements can only be realised through better control over the two processes comprising crystallization: nucleation and growth. Nucleation describes the initial stage of crystallization, whereby the first stable nuclei of the crystallizing phase are formed, whilst crystal growth considers the growth of these stable nuclei to larger dimensions. The aims of this proposal are two-fold. Firstly to perform fundamental studies on model systems to show how crystallization can be controlled at every stage and length scale, and secondly the implementation of these new advances into more complex systems to provide desirable outcomes. These include the production of crystals with well-defined size and shape, and the production of improved bone mimics. We intend to show how controlling crystallization can lead to the production of materials with vastly improved properties, which will ultimately rival those of biominerals.This work will involve the exploitation of key recent discoveries by Dr Cooper. In particular, Dr Cooper has pioneered the use of tunable nucleating systems to provide unprecedented control over nucleation rates. These results are accomplished by using emulsions, which are mixtures of oil droplets in water, or water droplets in oil. Normally, after mixing oil and water together, the two rapidly separate into a layer of oil on top of the water. However, if you add additives, known as surfactants, the small oil droplets can be stabilized and an emulsion is formed, like milk. We use special surfactants in our emulsions that promote nucleation, but only in a limited temperature regime, so that we can effectively switch crystallization on and off. This means we can obtain far greater control over the crystal size and shape, and the rate at which crystals are formed. Our systems can also be used to deliver anomalous effects. For instance, it is widely known that crystallization can occur on cooling a solution. This can be demonstrated readily by dissolving as much sugar as possible in hot water, and then letting the water cool. Using our systems, however, we can achieve crystallization on both heating and cooling.In the crystal growth field, we have used emulsions to create unusual crystal morphologies including porous crystals and crystals with intricate shapes resembling feathers and woven cloth. Such intricately-shaped crystals are normally only seen in biominerals, such as the skeletons produced by sea urchins. These effects are achieved by using oil droplets that adhere onto the growing crystal. If the crystal grows completely around the oil droplets, porous crystals can be produced. The intricately shaped crystals develop if crystal growth proceeds only on each side of the droplets, so that many crystal offshoots grow from the main crystal. The ability to produce such intricate morphologies from simple systems illustrates the effectiveness of crystal growth regulation. The holistic combination of tunable nucleation and growth inhibition via droplet adhesion will help provide the improved crystallization control necessary to achieve superior crystalline materials.

结晶是制备和生产固体材料（包括药品和特种产品）的最重要工艺之一;超过70%的固体以固体形式加工和利用。尽管如此突出，结晶领域可以说是潜在目标和实现目标之间差距最大的领域。生物矿物，如骨骼、贝壳和牙齿，表现出比合成矿物优越得多的上级性能，但由于我们不限于在环境温度和压力下加工，因此应该有可能改进自然界的设计策略。迫切需要在这一领域进行实质性改进，以生产具有明确尺寸、形状和结构的晶体，这对新兴纳米技术是如此必要。改进只能通过更好地控制包括结晶的两个过程来实现：成核和生长。成核描述了结晶的初始阶段，由此形成结晶相的第一稳定核，而晶体生长考虑这些稳定核向更大尺寸的生长。这项建议有两个目的。首先，对模型系统进行基础研究，以展示如何在每个阶段和长度尺度上控制结晶，其次，将这些新进展应用于更复杂的系统，以提供理想的结果。这些包括生产具有明确尺寸和形状的晶体，以及生产改进的骨模拟物。我们打算展示如何控制结晶可以导致生产的材料具有极大的改善性能，这将最终竞争对手的生物矿物质。这项工作将涉及利用库珀博士最近的关键发现。特别是，库珀博士率先使用可调成核系统，以提供前所未有的控制成核率。这些结果是通过使用乳液来实现的，乳液是油滴在水中或水滴在油中的混合物。通常情况下，在油和水混合在一起后，两者迅速分离成水面上的一层油。然而，如果你添加添加剂，称为表面活性剂，小油滴可以稳定和乳液形成，像牛奶。我们在乳液中使用特殊的表面活性剂来促进成核，但仅限于有限的温度范围，因此我们可以有效地开启和关闭结晶。这意味着我们可以更好地控制晶体的大小和形状，以及晶体形成的速度。我们的系统也可以用来提供异常效果。例如，众所周知，结晶可以在冷却溶液时发生。这可以通过将尽可能多的糖溶解在热水中，然后让水冷却来证明。然而，使用我们的系统，我们可以在加热和冷却的情况下实现结晶。在晶体生长领域，我们使用乳液创造了不寻常的晶体形态，包括多孔晶体和具有复杂形状的晶体，如羽毛和编织布。这种形状复杂的晶体通常只在生物矿物中看到，例如海胆产生的骨骼。这些效果是通过使用粘附在生长晶体上的油滴来实现的。如果晶体完全围绕油滴生长，则可以产生多孔晶体。如果晶体生长仅在液滴的每一侧进行，则会形成形状复杂的晶体，因此许多晶体分支从主晶体生长。从简单系统中产生如此复杂形态的能力说明了晶体生长调节的有效性。通过液滴粘附的可调成核和生长抑制的整体组合将有助于提供获得上级结晶材料所需的改进的结晶控制。