Martella Daniele, Nocentini Sara, Antonioli Diego, Laus Michele, Wiersma Diederik S, Parmeggiani Camilla
European Laboratory for Non-Linear Spectroscopy (LENS), via Nello Carrara 1, 50019 Sesto Fiorentino, Italy.
National Institute of Optics, CNR-INO, via Nello Carrara 1, 50019 Sesto Fiorentino, Italy.
Polymers (Basel). 2019 Oct 10;11(10):1644. doi: 10.3390/polym11101644.
The ability to obtain 3D polymeric objects by a 2D-to-3D shape-shifting method is very appealing for polymer integration with different materials, from metals in electronic devices to cells in biological studies. Such functional reshaping can be achieved through self-folding driven by a strain pattern designed into the molecular network. Among polymeric materials, liquid crystalline networks (LCNs) present an anisotropic molecular structure that can be exploited to tailor internal strain, resulting in a natural non-planar geometry when prepared in the form of flat films. In this article, we analyze the influence of different molecular parameters of the monomers on the spontaneous shape of the polymeric films and their deformation under different stimuli, such as heating or light irradiation. Modifying the alkilic chains of the crosslinkers is a simple and highly effective way to increase the temperature sensitivity of the final actuator, while modifying ester orientation on the aromatic core interestingly acts on the bending direction. Combining such effects, we have demonstrated that LCN stripes made of different monomeric mixtures originate complex non-symmetric deformation under light activation, thus opening up new applications in photonic and robotics.
通过二维到三维的形状转变方法获得三维聚合物物体的能力，对于聚合物与不同材料的整合非常有吸引力，这些材料涵盖了从电子设备中的金属到生物学研究中的细胞等各种类型。这种功能性重塑可以通过分子网络中设计的应变模式驱动的自折叠来实现。在聚合材料中，液晶网络（LCNs）呈现出一种各向异性的分子结构，可利用该结构来调整内部应变，从而在制备成平膜形式时产生自然的非平面几何形状。在本文中，我们分析了单体的不同分子参数对聚合物薄膜自发形状及其在不同刺激（如加热或光照）下变形的影响。改变交联剂的烷基链是提高最终致动器温度敏感性的一种简单且高效的方法，而有趣的是，改变芳香核上酯的取向会影响弯曲方向。综合这些效应，我们证明了由不同单体混合物制成的LCN条纹在光激活下会产生复杂的非对称变形，从而为光子学和机器人技术开辟了新的应用领域。
