The combination of flexibility and elasticity makes elastic materials essential in a wide range of industries, including automotive, construction, and consumer goods. Moreover, they are increasingly attractive in emerging fields such as microfluidics, soft robotics, wearables, and medical devices. However, having sufficient mechanical strength is a prerequisite for any application. Thus, solving the seemingly contradictory attributes between softness and strength has always been an eternal pursuit.
Natural spider silk has extraordinary strength, providing a continuous source of inspiration for designing synthetic soft materials. Though its unique superstructure is difficult to replicate, the more general principle of designing layered structures provides useful hints for designing elastic materials with high mechanical strength. However, the above design principles cannot be directly applied to digital light processing (DLP)-based 3D printing. DLP printing requires rapid light curing to achieve the necessary rapid gelling. Therefore, photopolymer resins typically contain a significant amount of multifunctional acrylates or methacrylates, severely limiting the freedom of molecular design. Additionally, rapid solidification can lead to uneven network formation and residual stresses, which are also detrimental to mechanical performance.
The potential for large-scale production of 3D printing is hindered by its low manufacturing efficiency (printing speed) and inadequate product quality (mechanical performance). The latest advances in ultrafast 3D printing of photopolymer alleviate the problem of manufacturing efficiency, but the typical mechanical properties of printed polymer are still far behind traditional processing techniques.
Recently, Professor Xie Tao and Associate Researcher Wu Jingjun's team from the School of Chemical Engineering and Bioengineering at Zhejiang University published an article titled "3D printable elastomers with exceptional strength and toughness" in Nature. The study reported a 3D photo printed resin chemistry that produced elastomers with a tensile strength of 94.6 MPa and a toughness of 310.4 MJ m-3, far exceeding any 3D printed elastomer. Mechanically speaking, this is achieved by printing dynamic covalent bonds in polymers, allowing for network topology reconfiguration and facilitating the formation of hierarchical hydrogen bonds (especially amide hydrogen bonds), microphase separation, and interpenetrating structures, thereby synergistically promoting excellent mechanical properties. This work provides a brighter future for large-scale manufacturing using 3D printing.
Figure 1: Chemical Design of 3D Photoprinted Elastomers © 2024 Springer Nature
Figure 2. Mechanical properties of elastomers and their strengthening and toughening mechanisms © 2024 Springer Nature
Figure 3. Elasticity and mechanical properties of elastomers © 2024 Springer Nature
Figure 4: Strong and tough elastomers printed by DLP © 2024 Springer Nature
The ability to 3D print super strong and ultra tough materials in this work extends its range of use under extremely harsh conditions, far beyond the two examples presented in the article. In addition, the printing precursor in this work was synthesized using readily available reagents in simple steps, ensuring its low cost. Although there are other established principles for designing polymers with superior mechanical properties, it is challenging to directly apply them to 3D printing because of the strict requirements for photo printing, including rapid gel under light and sufficient container life during printing and storage. Nevertheless, they provide useful insights for the future development of alternative high-performance 3D printing materials. Overall, the study suggests that 3D printing does not necessarily compromise mechanical performance, which clears a major obstacle for its future commercial implementation.
SAT NANO is a best supplier of metal powder and alloy powder for 3D printing in China, we also can supply 3D printing service, if you have any enquiry, please feel free to contact us at sales03@satnano.com
