Chirality Triggered Wettability Switching on Smart Polymer Surface

Guangyan Qing and Taolei Sun*

Adv. Mater. 2011, 23, 1615–1620

DOI: 10.1002/adma.201004082

Chiral recognition and enantioselective interaction for biomolecules are of fundamental importance in biological processes in nature, and also for various applications in biochemistry, medicine, and industry. For different chiral molecular species, a lot of synthetic chiral recognition systems have been developed, with purposes of chiral detection and separation, and asymmetric catalysis, etc. However, recognition is usually only the first step, and a more appealing task is to translate the chiral signals into other processes or macroscopic properties and functions of materials, which will bring great advantages to applications, but is quite challenging for chemists. Here we report the chirality triggered wettability switching on smart copolymer films containing dipeptide units. Monosaccharide enantiomers stereoselectively interact with L-dipeptide units, which is translated into differential conformational changes of copolymer chains via the cooperative hydrogen bonding interaction. It results in discrepant wettability responses with contact angle difference larger than 90^o on a textured substrate, being accompanied by changes of other film properties, e.g. volume. This work points a promising direction for developing novel chirality-responsive materials, which find broad applications in controllable chiral separation, chiral medicine, smart bio-devices, etc.

智能聚合物表面上的手性触发润湿性切换

生物分子的手性识别和对映选择性相互作用在自然界中的生物过程中以及生物化学，医学和工业中的各种应用中至关重要。对于不同的手性分子种类，已经开发了许多合成的手性识别系统，其目的是手性检测和分离，以及不对称催化等。然而，识别通常只是第一步，更有吸引力的任务是翻译手性信号进入其他过程或材料的宏观性质和功能，这将为应用带来巨大的优势，但对化学家来说是非常具有挑战性的。在这里，我们报告手性触发润湿性转换在含有二肽单元的智能共聚物薄膜上。单糖对映体与L-二肽单元立体选择性地相互作用，其通过协同氢键相互作用转化为共聚物链的差异构象变化。它导致差异的润湿性响应，在微纳米复合基底上的接触角差大于90°，伴随着其它膜性质的变化，例如，体积。这项工作为开发新型手性响应材料指明了一个有希望的方向，该材料在可控手性分离，手性医学，智能生物装置等领域具有广泛的应用。