The team from the University of California, San Diego (UC San Diego) has developed a new process to enhance the performance of liquid crystal elastomers (LCEs) through chain entanglement, with Chemfish's high-purity monomers serving as key support.

https://pubs.acs.org/doi/10.1021/acsami.5c04077

Recently, the research team led by Shengqiang Cai from UC San Diego published a significant achievement in ACS Applied Materials & Interfaces, revealing a novel method to significantly improve the thermomechanical properties of liquid crystal elastomers (LCEs) through mechanically kneaded-induced chain entanglement. In this study, our company Chemfish provided the high-purity monomer 4-(6-(acryloyloxy)hexyloxy) benzoate (C6BAPE, 97%) as a core raw material, offering critical support for constructing high-performance LCE networks and driving technological breakthroughs in the field of smart materials.

I. Research Background: Performance Bottlenecks and Innovation Paths of Smart Materials

Liquid crystal elastomers (LCEs) are a class of smart materials combining elasticity and liquid crystal anisotropy, holding broad application prospects in flexible robotics, sensors, actuators, and other fields. However, traditional LCEs suffer from issues such as mechanical property degradation at high temperatures and insufficient driving stress, limiting their practical applications. Previous research mainly focused on regulating crosslinking density, while the UC San Diego team first proposed enhancing performance through "construction of chain entanglement networks", opening a new direction for LCE design.

Manufacturing Process of Entangled LCE: The schematic illustrates the synthesis of LCE dough, followed by mechanical kneading to form highly entangled LCE. Compared with conventional LCEs, the kneading process induces a higher density of entanglements.

II. Core Achievements: Chain Entanglement Enables Multidimensional Performance Breakthroughs in LCEs

The research team introduced high-density chain entanglements into LCE polymer networks through a mechanical kneading process of repeated folding and compression. Experiments show that this method increases the strength of LCEs by 4 times, improves the fracture strain by 3 times, and maintains excellent mechanical stability at 150°C. Additionally, the driving stress of entangled LCEs is 1.6 times higher than that of conventional materials, with a significantly increased self-rupture resistance temperature, addressing the challenge of traditional LCEs' easy failure at high temperatures.

Fig. 2 Mechanical Properties of Entangled LCE: (a) Comparison of stress-strain curves between conventional and entangled LCEs at different strain rates. (b) Comparison of fracture toughness and fracture strain between entangled multi-domain LCEs and various other multi-domain LCEs in the literature.

More importantly, the chain entanglement process provides a new path for preparing single-domain LCEs. By forming an initial entangled network through kneading and combining it with UV crosslinking, the team successfully prepared single-domain LCEs with oriented liquid crystal mesogens, which exhibit optimal driving strain in the temperature range of 40–50°C and show no significant performance degradation after more than 10 thermal cycles, laying the foundation for the development of high-precision actuator devices.

III. Key Role of Chemfish Products: High-Purity Monomers Build Performance Foundations

In the material preparation process, Chemfish's C6BAPE monomer, as a core raw material containing liquid crystal mesogens, played an irreplaceable role:

• Precise Construction of Polymer Networks: C6BAPE reacts with the chain extender (EDDET) in an exact ratio of 50:49. Its high purity (97%) ensures the controllability of the polymerization reaction, avoiding impurities from interfering with the formation of chain entanglements.
• Endowing Materials with Smart Response Characteristics: The benzoate unit in the molecular structure acts as a liquid crystal mesogen, enabling LCE to have temperature-induced phase transition capability (nematic-isotropic phase transition), thus achieving thermally driven functions.
• Optimizing Entanglement Network Topology: The long-chain structure of C6BAPE provides an ideal molecular skeleton for mechanical kneading. The flexible chain segments after polymerization are more prone to form interlocking entanglements during kneading, thereby enhancing the strength and toughness of the material.

IV. Industry Impact and Future Outlook

Professor Shengqiang Cai, the corresponding author of this study, pointed out: "The combination of the chain entanglement process and Chemfish's high-purity raw materials has broken through the bottleneck of performance optimization for traditional LCEs. This not only provides a new method for smart actuator design but also can be extended to fields such as fibers and 3D printing structures." It is expected to be applied in scenarios such as flexible robots, adaptive optical devices, and biomedical implants in the future.

As a provider of high-end materials, CHEMFISH is committed to supplying high-quality functional molecules for cutting-edge material research. The achievements of this collaboration demonstrate the supporting value of high-purity raw materials for innovative technologies.