Asymmetric Nanopores for Fundamental Studies of Hindered Transport

用于受阻运输基础研究的不对称纳米孔

• 批准号: 1033203
• 负责人: Colin Wolden
• 金额: $ 29.29万
• 依托单位: Colorado School of Mines
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1033203&HistoricalAwards=false
• 关键词: Asymmetric; Nanopores; Fundamental; Studies; Hindered

1033203Wolden The objective of this research is to develop a simple approach for large area fabrication of asymmetric nanopores, which in turn will be employed for fundamental studies of hindered transport. The research will employ a new variant of pulsed plasma-enhanced chemical vapor deposition (PECVD) to digitally manipulate the openings of model supports. Pulsed PECVD has been engineered as an alternative to atomic layer deposition (ALD) for self-limiting growth of thin films (i.e. 1 Å/pulse). Through control of operating conditions the degree of conformality may be engineered, enabling digital control over pore closure without sacrificing the high porosity/permeability of the underlying supports. The well-defined geometry of the resulting nanopores will serve as model systems for fundamental studies of hindered transport. Well-characterized proteins and inorganic quantum dots will be explored as model solutes. Surface effects often dominate at the length scales in question. This issue will be investigated by using established self-assembly techniques to systematically manipulate the surface termination of both pores and nanoparticles. The basic precepts have been demonstrated in preliminary work using anodized alumina supports. However, these studies also revealed that the pore size distribution in these commercial supports was inadequate for control at the nanoscale. This limitation will be remedied by employing uniform silicon supports fabricated using e-beam lithography through a collaboration with the Center for Nanophase Materials Sciences at ORNL. Intellectual Merit The intellectual merit of this proposal is in nanopore fabrication, thin film deposition, and nanoscale transport phenomena. Existing approaches for nanopore synthesis employ energetic beam technologies that are not amenable to large scale fabrication. The PI's approach employs standard integrated circuit (IC) fabrication techniques and is performed at ambient temperature. Feature scale models will be developed to simulate pore closure by pulsed PECVD, and validated using cross section microscopy. The resulting nanopores will have well-defined cylindrical geometries, creating an ideal platform for rigorous evaluation of theoretical models of hindered transport. Experimental measurements of permeance and solute rejection will be used to test and improve understanding of transport at the nanoscale. Broader Impacts Large area synthesis of well-defined nanopores would be an enabling innovation for the separation of both biological constituents and nanoparticles. Moreover, the resulting channels will serve as an ideal platform for experimental investigations of nanofluidics. The coupling of nanofluidics with electrical manipulation of charged species such as ions and DNA offers a potential alternative to conventional IC technology. The use of silicon wafers as the support structure will facilitate the integration of nanopore arrays with conventional electronic and microfluidic components for Lab-on-a-Chip applications. The broader impacts also include the training of a PhD candidate and the engagement of undergraduate researchers in areas of great technological importance. The PI and his students will continue their work with the CSM K-12 outreach team, developing teacher workshop materials related to membranes and water purification for school districts with large populations of underrepresented students.

小行星1033203 本研究的目的是开发一种简单的方法来大面积制造不对称的纳米孔，这反过来又将用于受阻传输的基础研究。该研究将采用脉冲等离子体增强化学气相沉积（PECVD）的新变体来数字化操纵模型支撑件的开口。脉冲PECVD已被设计为原子层沉积（ALD）的替代方案，用于薄膜的自限制生长（即1 μ m/脉冲）。通过控制操作条件，可以设计保形程度，从而能够对孔隙闭合进行数字控制，而不牺牲下层支撑物的高孔隙度/渗透率。所得到的纳米孔的定义明确的几何形状将作为模型系统的基础研究受阻运输。良好的特征蛋白质和无机量子点将被探索作为模型溶质。表面效应往往在所讨论的长度尺度上占主导地位。这个问题将通过使用已建立的自组装技术来系统地操纵孔和纳米颗粒的表面终止来研究。基本概念已在使用阳极氧化铝载体的初步工作中得到证实。然而，这些研究还揭示了这些商业载体中的孔径分布不足以在纳米级进行控制。通过与ORNL的纳米相材料科学中心合作，使用电子束光刻制造的均匀硅支撑将弥补这一限制。这个建议的智力价值在于纳米孔制造，薄膜沉积和纳米级传输现象。现有的纳米孔合成方法采用不适合大规模制造的高能束技术。PI的方法采用标准集成电路（IC）制造技术，并在环境温度下进行。将开发特征尺度模型以模拟脉冲PECVD的孔隙闭合，并使用横截面显微镜进行验证。由此产生的纳米孔将具有明确定义的圆柱形几何形状，为严格评估受阻传输的理论模型创造了理想的平台。渗透率和溶质排斥的实验测量将用于测试和提高对纳米级传输的理解。大面积合成明确的纳米孔将是分离生物成分和纳米颗粒的一项创新。此外，由此产生的通道将作为一个理想的平台，纳米流体的实验研究。纳米流体与带电物质（如离子和DNA）的电操纵的耦合提供了传统IC技术的潜在替代方案。使用硅晶片作为支撑结构将促进纳米孔阵列与用于芯片实验室应用的常规电子和微流体组件的集成。更广泛的影响还包括博士生的培训和本科生研究人员在具有重大技术意义的领域的参与。PI和他的学生将继续与CSM K-12外展团队合作，为代表性不足的学生人数众多的学区开发与膜和水净化相关的教师研讨会材料。