Permselective Ion Transport Across the Nanoscopic Liquid/Liquid Interface Array
Permselective Ion Transport Across the Nanoscopic Liquid/Liquid Interface Array
复制标题
跨纳米液/液界面阵列的选择性渗透离子传输
DOI：
10.1021/acs.analchem.6b01383
复制
发表时间：
2016-06-21
影响因子：
7.4
通讯作者：
Su, Bin
中科院分区：
文献类型：
--
作者：
Huang, Xiao;Xie, Lisiqi;Su, Bin
利用具有穿孔通道的自支撑二氧化硅纳米通道膜(SNM)在两种不相容的电解液(Nano-ity)之间形成纳米尺度的界面阵列，在该界面上实现了离子的选择性传输和检测。SNM由直径为2-3 nm、长度为70 nm的高密度直线纳米通道组成。用直径为5微米的150 nm厚的多孔氮化硅薄膜(p-SiNF)作为支撑材料，以纳米沟道-微孔的形式支撑SNM。考虑到材料表面的亲油性，在SNM和p-SinF的交界处形成了纳米阵列，扩散几何相当于两个背靠背镶嵌的微盘界面。因此，四乙基铵(TEA(+))在纳米阵列上的转移产生了对称的S型电流响应。此外，由于二氧化硅纳米通道的超小尺寸和带负电荷的表面，纳米颗粒表现出明显的尺寸和电荷选择性能。大小与纳米通道相当或大于纳米通道的离子的转移被空间阻挡。尺寸小于纳米通道的阴离子受到通道壁的强烈静电斥力，表现出明显的水溶液离子强度依赖性。本方法在离子检测和分离方面具有潜在的应用前景，是构建纳米阵列的一种简便和廉价的方法。
Free-standing silica nanochannel membrane (SNM) with perforated channels was utilized to create arrays of nanoscale interfaces between two immiscible electrolyte solutions (nano-ITIES), at which permselective ion transfer and detection were achieved. The SNM consisted of a high density of straight nanochannels with a diameter of 2-3 nm and a length of 70 nm. The silicon wafer coated by 150 nm-thick porous silicon nitride film (p-SiNF) with pores of 5 mu m-in-diameter was used to support the SNM in a form of nanochannel-on-micropore. Considering the material surface lipophilicity, the nano-ITIES array was formed at the boundary between SNM and p-SiNF, with a diffusion geometry equivalent to two back-to-back inlaid microdisc interfaces. Thus, the transfer of tetraethylammonium (TEA(+)) across the nano-ITIES array yielded symmetric sigmoidal current responses. In addition, because of the ultrasmall size and negatively charged surface of silica nanochannels, the nano-ITIES displayed obvious size and charge permselectivities. Transfer of ions with a size comparable with or larger than the nanochannel was sterically blocked. Also that of anions with a size smaller than the nanochannels encountered the strong electrostatic repulsion from channel walls, showing obvious dependence on the ionic strength of aqueous solution. The present approach is facile and inexpensive for building a nano-ITIES array with potential applications in ion detection and separation.