Liquid crystalline networks (LCNs) are a class of polymers, which are able to produce mechanical actuation in response to external stimuli. Recent creation of LCNs with exchangeable links (xLCNs) makes LCNs easy moldable. As the xLCNs need to be shaped at a high temperature, it is important to enhance their thermal and mechanical properties. In this paper, a series of xLCNs/SiO₂ composites containing 1%-7% SiO₂ nanoparitcles (SNP) were prepared and their thermal and mechanical properties were examined. The results show that xLCNs/SNP composites have lower liquid crystalline-isotropic phase transition temperature and higher decomposition temperature than pure LCN. The tensile strength and the elongation at break of xLCNs at high temperatures were also enhanced due to the addition of SNPs.

Photo-active shape memory polymers (SMPs) are considered as a promising candidate for converting light into mechanical energy. However, most known SMPs are only thermo-responsive. To achieve photo-activity, photo-responsive choromophores or fillers usually have to be incorporated from the very beginning of the material synthesis. Here, we introduce a novel post-synthesis approach to endow normal SMPs with photo-active properties using mussel-inspired surface chemistry. Without changing the original properties, the resultant polydopamine (PDA) coated SMPs show an efficient photo-active performance. The coating can be easily patterned and erased, which allows flexible light-triggered 3-D shape deformation of a planar SMP sheet. Moreover, owing to the high chemical activity, the PDA coating also provides a platform to optimize the surface properties of the photo-responsive SMPs through secondary surface modification.