Shin Woohyeon, Chung Kyeongwoon
Department of Biofibers and Biomaterials Science, Kyungpook National University, Daegu 41566, Republic of Korea.
School of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea.
Materials (Basel). 2023 Mar 3;16(5):2085. doi: 10.3390/ma16052085.
The three-dimensional (3D) printing of hydrogel is an issue of interest in various applications to build optimized 3D structured devices beyond 2D-shaped conventional structures such as film or mesh. The materials design for the hydrogel, as well as the resulting rheological properties, largely affect its applicability in extrusion-based 3D printing. Here, we prepared a new poly(acrylic acid)-based self-healing hydrogel by controlling the hydrogel design factors based on a defined material design window in terms of rheological properties for application in extrusion-based 3D printing. The hydrogel is designed with a poly(acrylic acid) main chain with a 1.0 mol% covalent crosslinker and 2.0 mol% dynamic crosslinker, and is successfully prepared based on radical polymerization utilizing ammonium persulfate as a thermal initiator. With the prepared poly(acrylic acid)-based hydrogel, self-healing characteristics, rheological characteristics, and 3D printing applicability are deeply investigated. The hydrogel spontaneously heals mechanical damage within 30 min and exhibits appropriate rheological characteristics, including G'1075 Pa and tan δ0.12, for extrusion-based 3D printing. Upon application in 3D printing, various 3D structures of hydrogel were successfully fabricated without showing structural deformation during the 3D printing process. Furthermore, the 3D-printed hydrogel structures exhibited excellent dimensional accuracy of the printed shape compared to the designed 3D structure.
水凝胶的三维（3D）打印是一个在各种应用中备受关注的问题，其目的是构建超越二维形状的传统结构（如薄膜或网）的优化三维结构装置。水凝胶的材料设计以及由此产生的流变特性，在很大程度上影响其在基于挤出的3D打印中的适用性。在此，我们通过在基于流变特性的定义材料设计窗口内控制水凝胶设计因素，制备了一种新型的基于聚丙烯酸的自愈合水凝胶，用于基于挤出的3D打印。该水凝胶设计为具有1.0 mol%共价交联剂和2.0 mol%动态交联剂的聚丙烯酸主链，并利用过硫酸铵作为热引发剂通过自由基聚合成功制备。利用制备的基于聚丙烯酸的水凝胶，深入研究了其自愈合特性、流变特性和3D打印适用性。该水凝胶在30分钟内可自发修复机械损伤，并表现出适用于基于挤出的3D打印的流变特性，包括G'1075 Pa和tan δ0.12。在3D打印应用中，成功制造了各种水凝胶三维结构，且在3D打印过程中未出现结构变形。此外，与设计的三维结构相比，3D打印的水凝胶结构在打印形状上表现出优异的尺寸精度。
