NER: Ordered liquid crystal nano-colloids

NER：有序液晶纳米胶体

• 批准号: 0508137
• 负责人: John West
• 金额: $ 10万
• 依托单位: Kent State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2007-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0508137&HistoricalAwards=false
• 关键词: NER; Ordered; liquid; crystal; nano

Complex three dimensional structures of nanoparticles can be produced in liquid crystals. Our preliminary research demonstrates that a moving liquid crystal to isotropic phase boundary collects and pushes and periodically deposits nanoparticles. By adjusting a variety of conditions, such as the rate of the phase transition, the alignment of type of liquid crystal, the size and shape of particles, we can produce a wide variety of three dimensional structures. We have also found that application of external fields and in particular patterned external fields can be combined with the phase transition to produce very complex structures. This proposal outlines an aggressive research project to explore the basic mechanisms of these newly discovered phenomena potential to produce complex three dimensional structures. This project is most closely related to the Nanoscale Structures, Novel Phenomena and Manufacturing Processes at the Nanoscale, while having relevance for the Nanoscale Devices and System Architecture theme.We propose to deploy the unique research strengths at the Liquid Crystal Institute (Kent State University, Ohio) to rapidly result in new electro-optical materials and establish a theoretical base to understand this complex process We will focus on precisely controlling the position of nano-particles dispersed in liquid crystalline matrices. Particles dispersed in the liquid crystal phase produce distortions in the liquid crystal director and introduce defects in the liquid crystal phase. The added energy found in these distortions and defects provide the forces that move the nanoparticles. In order to minimize the free energy of the system, particles will share defects and tend to form organized structures. These structures will tend to reside at defect lines and planes separating liquid crystal domain providing the simplest mechanism to produce complex three dimensional structures.Anchoring at the particle surface can induce a gradient in the magnitude of the nematic order parameter in their neighborhood, leading to an attractive short-range interaction between particles. More complex interactions arise from restrictions of thermal fluctuations in the director field near the particle surfaces. By modulating these complex systems of energies we have the potential to precisely control the placement of nano-particles.As an example of the power of this new approach we will build complex three dimensional photonic crystals that arrange particles of different sizes and physical properties in ordered arrays. For example we can segregate particles of different types: ferro-electric, ferro-magnetic, and carbon nanotubes. The elastic, electro-, magneto-, and nonlinear optical properties of these suspensions will be investigated experimentally and theoretically as a function of the physical properties, concentration, size, and shape of the particles. These complex arrays can be used to produce new optical devices, artificial muscles, responsive membranes and biological sensors.Intellectual meritThe result of our research will be a new set of tools researchers can use to build nano-particle structures and create entirely new affects. We will also expand our general understanding of the liquid crystal phase. For example, we have already found that the movement of nanoparticles at the isotropic interface provides new insight into the properties of this complex boundary.Broader impactWe will utilize our existing Industrial Partnership Program to assure that our results are quickly transmitted to the marketplace. Through the LCI summer internship program and the KSU REU program we will reach out to undergraduate students and through our established education outreach program we will interact with K-12 students in the area.

纳米颗粒的复杂三维结构可以在液晶中产生。 我们的初步研究表明，一个移动的液晶各向同性相界收集和推动，并定期沉积纳米粒子。通过调节各种条件，例如相变的速率、液晶类型的取向、颗粒的大小和形状，我们可以产生各种各样的三维结构。我们还发现，施加外部场，特别是图案化的外部场，可以与相变相结合，以产生非常复杂的结构。该提案概述了一个积极的研究项目，以探索这些新发现的现象的基本机制，这些现象可能产生复杂的三维结构。本计画与奈米结构、奈米新现象及奈米制程相关，并与奈米元件及系统架构相关，建议利用液晶研究所的研究优势，（肯特州立大学，俄亥俄州）迅速产生新的电-光学材料，并建立一个理论基础，以了解这一复杂的过程，我们将专注于精确控制分散在液晶矩阵中的纳米粒子的位置。分散在液晶相中的颗粒在液晶指向矢中产生畸变并在液晶相中引入缺陷。在这些扭曲和缺陷中发现的额外能量提供了移动纳米颗粒的力。为了使系统的自由能最小化，粒子将共享缺陷并倾向于形成有组织的结构。这些结构将倾向于驻留在分离液晶畴的缺陷线和平面上，提供了产生复杂三维结构的最简单机制。在颗粒表面的聚集可以在其邻域中诱导有序参数的大小的梯度，导致颗粒之间有吸引力的短程相互作用。更复杂的相互作用来自于粒子表面附近指向矢场中的热涨落的限制。通过调节这些复杂的能量系统，我们有可能精确地控制纳米粒子的位置。作为这种新方法的力量的一个例子，我们将构建复杂的三维光子晶体，将不同尺寸和物理性质的粒子排列成有序阵列。例如，我们可以分离不同类型的粒子：铁电，铁磁和碳纳米管。这些悬浮液的弹性，电，磁，和非线性光学性质将实验和理论上作为一个功能的物理性质，浓度，尺寸和形状的颗粒。这些复杂的阵列可以用来制造新的光学器件、人造肌肉、响应膜和生物传感器。智力价值我们的研究成果将是一套新的工具，研究人员可以用它来构建纳米颗粒结构，创造全新的影响。我们还将扩展我们对液晶相的一般理解。例如，我们已经发现纳米粒子在各向同性界面上的运动，这为了解复杂边界的性质提供了新的视角。更广泛的影响我们将利用现有的工业合作伙伴计划，确保我们的结果迅速传递到市场。通过LCI暑期实习计划和KSU REU计划，我们将接触本科生，并通过我们既定的教育推广计划，我们将与该地区的K-12学生互动。