使用可调的纳米孔阻断率来研究胶体分散体
Use of tunable nanopore blockade rates to investigate colloidal dispersions
摘要：
弹性体膜中的可调纳米孔已被用于研究离子电流阻断速率对水性悬浮液中颗粒的浓度和电泳迁移率的依赖性。已经测试了一系列纳米颗粒尺寸、材料和表面功能。利用压力驱动的流动通过一个孔，发现100 nm羧基化聚苯乙烯颗粒的阻滞率与跨膜压力（控制在0 ~ 1.8 kPa之间）和颗粒浓度（在7 x 10^8 ~ 4.5 x 10^10 mL^-1之间）成线性比例。这个结果可以用能斯特-普朗克输运理论精确地模拟。仅使用一个施加的电位在一个孔，羧酸和胺涂覆的500 nm和200 nm的二氧化硅颗粒的封锁率被发现对应于其流动性的变化作为溶液pH值的函数。扫描电子显微镜和共聚焦显微镜已被用来可视化的可调纳米孔几何形状的变化在三维中作为施加的机械应变的函数。观察到的孔是圆锥形的形状，和孔径的变化是一致的离子电流测量。孔附近的非弹性变形区已被确定为在调谐过程中的关键。
英文摘要：
Tunable nanopores in elastomeric membranes have been used to study the dependence of ionic current blockade rate on the concentration and electrophoretic mobility of particles in aqueous suspensions. A range of nanoparticle sizes, materials and surface functionalities has been tested. Using pressure-driven flow through a pore, the blockade rate for 100 nm carboxylated polystyrene particles was found to be linearly proportional to both transmembrane pressure (controlled between 0 and 1.8 kPa) and particle concentration (between 7 x 10^8 and 4.5 x 10^10 mL^-1). This result can be accurately modelled using Nernst-Planck transport theory. Using only an applied potential across a pore, the blockade rates for carboxylic acid and amine coated 500 nm and 200 nm silica particles were found to correspond to changes in their mobility as a function of the solution pH. Scanning electron microscopy and confocal microscopy have been used to visualise changes in the tunable nanopore geometry in three dimensions as a function of applied mechanical strain. The pores observed were conical in shape, and changes in pore size were consistent with ionic current measurements. A zone of inelastic deformation adjacent to the pore has been identified as critical in the tuning process.
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