Laboratory of Functional Organic Materials & Devices (SFD), Department of Chemical Engineering & Chemistry, Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven (The Netherlands).
Angew Chem Int Ed Engl. 2014 Apr 25;53(18):4542-6. doi: 10.1002/anie.201400370. Epub 2014 Mar 11.
Chiral-nematic polymer network coatings form a "fingerprint" texture through self-assembly. For this purpose the molecular helix of the coating is oriented parallel to the substrate. The coating has a flat surface but when actuated by light in the presence of a copolymerized azobenzene compound, 3D fingerprint structures appear in the coating. The helix forms protrusions at the positions where the molecules are aligned parallel to the surface and withdraws at the positions where the orientation is perpendicular. This process proceeds rapidly and is reversible, that is, the fingerprint-shaped protrusions disappear when the light is switched off. The texture in the on-state resembles that of a human fingerprint and is used to manipulate the gripping friction of a robotic finger. The friction coefficient drops by a factor of four to five when the fingerprint switched on because of reduced surface contacts.
手性向列聚合物网络涂层通过自组装形成“指纹”纹理。为此，涂层的分子螺旋平行于基底取向。涂层具有平坦的表面，但在光的作用下，在共聚偶氮苯化合物存在下，涂层中会出现 3D 指纹结构。螺旋在分子平行于表面排列的位置形成突起，在取向垂直的位置缩回。这个过程进行得很快而且是可逆的，也就是说，当关闭光时，指纹状的突起就会消失。开启状态下的纹理类似于人类指纹，用于操纵机器人手指的抓握摩擦力。由于表面接触减少，当指纹开启时，摩擦系数下降了四到五倍。
