Zimnitsky Dmitry, Shevchenko Valeriy V, Tsukruk Vladimir V
Georgia Institute of Technology, School of Materials Science and Engineering, Atlanta, Georgia 30332, USA.
Langmuir. 2008 Jun 17;24(12):5996-6006. doi: 10.1021/la7038575. Epub 2008 May 6.
Ultrathin, perforated, and freely suspended membranes with uniform nanopores in the range of tens of nanometers have been fabricated using a fast, simple method of spin-assisted layer-by-layer assembly on hydrophobic substrates. Membranes with thicknesses down to 20 nm were robust enough to be released from the sacrificial substrates, transferred onto various surfaces, and suspended over microscopic openings. The nanopore size can be controlled by tuning the number of polyelectrolyte bilayers, spinning speed, and a proper selection of hydrophobic substrates. We demonstrate that the formation of nanopores is caused by the partial dewetting of polyelectrolyte layers in the course of their deposition on the underlying hydrophobic surfaces. The nanoscale thickness of perforated membranes with relatively uniform size and a high concentration of nanopores provides perspectives for higher rates of transport through freely suspended LbL membranes. The highly perforated LbL membranes introduced here can serve as a novel platform for ultrafine separation considering an intriguing combination of nanopores, nanoscale membrane thickness, and easy functionalization.
利用一种快速、简单的在疏水基底上进行旋转辅助逐层组装的方法，制备出了具有数十纳米范围内均匀纳米孔的超薄、穿孔且自由悬浮的膜。厚度低至20纳米的膜足够坚固，能够从牺牲基底上释放出来，转移到各种表面上，并悬浮在微观开口上方。纳米孔的尺寸可以通过调整聚电解质双层的数量、旋转速度以及对疏水基底的适当选择来控制。我们证明，纳米孔的形成是由于聚电解质层在沉积到下层疏水表面过程中的部分去湿所致。具有相对均匀尺寸和高浓度纳米孔的穿孔膜的纳米级厚度为通过自由悬浮的逐层组装膜实现更高的传输速率提供了前景。考虑到纳米孔、纳米级膜厚度和易于功能化的有趣组合，这里介绍的高度穿孔的逐层组装膜可以作为一种用于超细分离的新型平台。
