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.

这项研究的目标是开发一种简单的方法来大面积制造不对称纳米孔，这反过来将被用于受阻传输的基础研究。这项研究将使用一种新的脉冲等离子体增强化学气相沉积(PECVD)来数字操作模型支架的开口。脉冲PECVD已被设计为原子层沉积(ALD)的一种替代方案，用于自限幅薄膜生长(即1？/PULSE)。通过控制操作条件，可以设计一致性程度，实现对孔道闭合的数字控制，而不会牺牲底层支架的高孔隙率/渗透率。由此形成的纳米孔的明确几何形状将作为阻碍传输的基础研究的模型系统。具有良好特性的蛋白质和无机量子点将作为模型溶质进行探索。表面效应通常在所讨论的长度尺度上占主导地位。这一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进行研究。这些基本原则已经在使用阳极氧化氧化铝支架的初步工作中得到了验证。然而，这些研究也表明，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的纳米材料科学中心合作，使用电子束光刻技术制造的均匀硅载体将弥补这一限制。这一提议的学术价值在于纳米孔的制造、薄膜沉积和纳米尺度的传输现象。现有的纳米孔合成方法使用的是不适合大规模制造的高能束流技术。PI的方法采用标准集成电路(IC)制造技术，并在常温下进行。将开发特征尺度模型来模拟脉冲PECVD的孔洞闭合，并用横截面显微镜进行验证。由此产生的纳米孔将具有定义良好的圆柱形几何形状，为严格评估受阻传输的理论模型创造了一个理想的平台。将使用渗透率和溶质排斥的实验测量来测试和改进对纳米尺度传输的理解。更广泛的影响，大面积合成定义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，由此产生的通道将成为纳米流体实验研究的理想平台。纳米流体与带电物种(如离子和DNA)的电操纵相结合，为传统IC技术提供了一种潜在的替代方案。使用硅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传统电子和微流控部件的集成。更广泛的影响还包括对博士生的培训和本科生研究人员在具有重大技术重要性的领域的参与。PI和他的学生将继续与CSM K-12外联小组合作，为学生人数较少的学区开发与膜和水净化有关的教师工作坊材料。