Fabrication of polymer micro- and nanotubes with use of self-scrolling effect of strained thin polymer bilayer films.

最近，我们开发了一种利用应变聚合物双层膜的自卷曲来制备介观直径和高深宽比的聚合物管的新方法。薄膜中的应变是由于组成双层的顶部和底部的聚合物在选择性溶剂中的不同溶胀而产生的。管状结构是在薄膜从衬底受控释放时形成的。我们用这种技术制备了直径从200 nm到5微米、长径比高达数百的聚苯乙烯-聚乙烯基吡啶管材。这种方法的主要优点是可以对内管表面进行复杂的功能化。在卷轴之前，可以将聚合物薄膜暴露在高度发展的平面表面功能化方法(微接触印刷、光刻)中。这原则上允许在管子内部创建非平凡的三维图案排列，例如螺旋、环等。具有复杂功能化内表面的管子可用于胶体颗粒和大分子的模板辅助自组装、蛋白质和其他生物分子与管壁的特定空间相互作用等。通过选择性地对管子的图案化内表面进行金属化，可以制造有趣的物理装置，例如纳米胶体。在该项目中，我们追求两个主要目标。首先，我们计划优化纳米管的制造技术，以使管的直径最小化。通过使用嵌段共聚物，在选择性衬底上形成层状结构，从而减少应变聚合物双层的厚度。通过这种方式，我们希望生产出直径只有几十纳米的管子。我们还打算制造从亚微米到亚毫米尺度的不同直径的管子。这些管子可用于纳米设备的介观操作部分和宏观环境(试剂供应等)的输入-输出连接。其次，我们计划通过将微接触印刷和光刻技术与自卷曲效应相结合，制造出内表面具有简单非平凡图案的管子。

Recently we have developed a novel method of producing polymer tubes of mesoscopic diameter and high aspect ratio with use of self-scrolling of strained polymer bilayer films. The strain in the film arises due to different swelling of the polymers, composing the top and the bottom parts of the bilayer, in a selective solvent. Tubular structures are formed upon controlled release of the film from the substrate. We have fabricated by this technique the polystyrene-polyvinylpyridine tubes with the diameters ranging from 200 nm to 5 microns and aspect ratios up to several hundreds. The major advantage of the approach is the possibility of complex functionalization of the inner tube surface. Before the scrolling, the polymer film can be exposed to highly developed planar methods of surface functionalization (micro-contact printing, photolithography). This allows in principle to create non-trivial 3-D arrangement of patterns inside the tubes, such as helices, rings, etc. The tubes with complex functionalized inner surface can be useful for template-assisted self-assembly of colloidal particles and macromolecules, specific steric interaction of proteins and other biomolecules with the tube walls, etc. Interesting physical devices, such as nanosolenoids, can be produced by selective metallisation of the patterned internal surface of the tubes. Within the project, we pursue two major goals. First, we plan to optimize the technique of nanotube fabrication in order to minimize the diameter of the tubes. The thickness of the strained polymer bilayer will be reduced by the use of block-copolymers, which form layered structure on selective substrates. In this way we hope to produce the tubes with diameter as small as few dozens of nanometers. We intend also to fabricate the tubes of varying diameter ranging from sub-micron to sub-millimeter scale. These tubes could be useful for input-output connection of mesoscopic operational parts of the nanodevices and the macroscopic environment (supplies of reagents, etc.). Second, we plan to fabricate the tubes with simple non-trivial patterning of the internal surface by combining the micro-contact printing and photolithography with the self-scrolling effect.