Myelin Figures: Non-equilibrium organization of amphiphiles induced by hydration

髓磷脂图：水合诱导的两亲物的非平衡组织

• 批准号: 2104123
• 负责人: Atul Parikh
• 金额: $ 49.14万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2104123&HistoricalAwards=false
• 关键词: Myelin; Figures; Non; equilibrium; organization

Non-Technical Abstract: Oil and water do not mix. But many ordinary soaps and detergent negate this proverbial expression by allowing the two substances to mix. Called surfactants, these soft and fragile materials interact with water (or oil) in complex, subtle, and nuanced manners. Their dissolution in water is often accompanied by the formation of unusual structures that extend far beyond the sizes of molecules producing a dynamic mosaic that characterize the surfactant-laden aqueous phase. One such example is the formation of a class of finger-like cylindrical protrusions called myelin figures, tens of micrometers in diameters and hundreds of micrometers in length, which appear when a dry mass of surfactant meets water. This project involves controlled laboratory experiments to study their formation, direct their growth, and exploit their morphologies to produce novel nanomaterials. The findings of the project should benefit many areas of applications, including food, cosmetics, soap, and dispersion technologies. The project includes the training and participation of a graduate student and a post-doc in the scientific process. It also engages undergraduate students and underrepresented groups in STEM through the Vertically-Integrated Program, which offers Science & Society credits and opportunities for laboratory research over multiple years on a single, consolidated project.Technical Abstract: The equilibration of complex fluids is often accompanied by unusual instabilities as they progress toward equilibrium. This is perhaps best exemplified by myelinic instabilities, which emerge when an insoluble surfactant meets water. The individual myelins ¬– cylindrical smectic liquid crystals tens of micrometers in diameter and hundreds of micrometers in length – grow sinuously, by a two-dimensional reptation-like motion, which tightly juxtapose with their neighbors; elongate, cooperatively; and, often fold morphologically, into symmetry-breaking helical shapes. This project seeks to understand their formation mechanisms, control their spatial organization, investigate their responsiveness to environmental perturbations, and exploit their nanometer scale confinements to template synthesis of nanostructures. It experimentally tests the hypothesis that the intrinsically non-equilibrium process of amphiphilic hydration can be controllably tuned to lift equilibrium constraints, dial-in structural instabilities, and kinetically trap long-lived metastable states within the free energy landscape that characterizes the hydration process. It also seeks to exploit myelin figures as self-organizing dynamic templates to synthesize nanoscale materials into hierarchical, extended, and complex superlattices. Using a combination of microscopy based quantitative measurements, the planned research activities include(1) develop methods to control the spatial organization of myelin figures (taming the chaos); (2) characterizing phase-separating mixtures of amphiphiles within myelin morphologies (introducing chemical diversity); (3) accessing higher-order, symmetric breaking organization of myelin figures by coupling physical-chemical stress from their local microenvironment (shape-shifting myelins); and (4) templating synthesis of nanomaterials by exploiting myelinic confinement (templated nanosynthesis). The effort should yield new insights into non-equilibrium routes for controlling supramolecular organization and novel approaches for synthesis-with-design.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术摘要：油和水不能混合。但许多普通的肥皂和洗涤剂通过允许这两种物质混合而否定了这一谚语。这些柔软易碎的材料被称为表面活性剂，它们与水（或油）以复杂、微妙和微妙的方式相互作用。它们在水中的溶解通常伴随着不寻常结构的形成，这些结构远远超出分子的大小，产生动态马赛克，这是负载表面活性剂的水相的特征。其中一个例子就是形成一种像手指一样的圆柱形突起，称为髓鞘图，直径数十微米，长度数百微米，当干燥的表面活性剂遇到水时就会出现。该项目包括受控的实验室实验来研究它们的形成，指导它们的生长，并利用它们的形态来生产新的纳米材料。该项目的研究结果将有利于许多应用领域，包括食品、化妆品、肥皂和分散技术。该项目包括一名研究生和一名博士后在科学过程中的培训和参与。它还通过垂直整合计划（vertical - integrated Program）吸引STEM领域的本科生和代表性不足的群体，该计划为一个单一的综合项目提供科学与社会学分和多年的实验室研究机会。技术摘要：复杂流体在趋于平衡的过程中往往伴随着不寻常的不稳定性。髓鞘不稳定性也许是最好的例子，当不溶性表面活性剂遇到水时，就会出现髓鞘不稳定性。单个髓鞘——直径数十微米、长度数百微米的圆柱形近晶液晶——以一种二维重复运动的方式蜿蜒生长，它们与相邻的髓鞘紧密并列；拉长,合作;并且，通常在形态上折叠成打破对称的螺旋形状。该项目旨在了解它们的形成机制，控制它们的空间组织，研究它们对环境扰动的响应，并利用它们在纳米尺度上的局限性来合成纳米结构模板。实验验证了两亲水化过程的内在非平衡过程可以被可控地调整，以解除平衡约束，调节结构不稳定性，并在表征水化过程的自由能环境中动态捕获长寿命的亚稳态。它还试图利用髓磷脂图形作为自组织动态模板，将纳米级材料合成成分层的、扩展的和复杂的超晶格。利用结合显微镜的定量测量，计划的研究活动包括：(1)开发控制髓鞘图形空间组织的方法（驯服混乱）；(2)表征髓鞘形态中两亲分子的相分离混合物（引入化学多样性）；(3)通过耦合来自局部微环境（形状变化的髓磷脂）的物理化学应力，获得髓磷脂图形的高阶对称断裂组织；(4)利用髓鞘约束进行纳米材料模板合成（模板纳米合成）。这一努力将对控制超分子组织的非平衡途径和设计合成的新方法产生新的见解。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Nonequilibrium Self-Organization of Lipids into Hierarchically Ordered and Compositionally Graded Cylindrical Smectics

• DOI: 10.1021/acs.langmuir.1c02576
• 发表时间: 2022-01-12
• 期刊: LANGMUIR
• 影响因子: 3.9
• 作者: Ho, James C. S.;Su, Wan-Chih;Liedberg, Bo
• 通讯作者: Liedberg, Bo