当前位置: X-MOL 学术J. Manuf. Process. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
3D freeze-printed cellulose-based aerogels: Obtaining truly 3D shapes, and functionalization with cross-linking and conductive additives
Journal of Manufacturing Processes ( IF 6.2 ) Pub Date : 2021-06-05 , DOI: 10.1016/j.jmapro.2021.05.051
Halil Tetik , Keren Zhao , Nasrullah Shah , Dong Lin

Cellulose is the most abundant natural polymer existing on earth and nanomaterials derived from cellulose have been used in variety of applications. There is a great research interest in aerogels based on cellulosic nanomaterials due to their ultra-low thermal conductivity, modulus, sonic velocity, refractive index, dielectric constant, high specific surface area, and adjustable density. 3D printing of cellulose-based aerogels provided an ability to fabricate complex geometries with designed pore morphologies, which can be advantageous for various applications. Yet, the complexity of the geometry still has a limitation due to the lack of support material that can be removed from the structure without using harsh and tedious chemical / thermal processes that may affect the cellulosic material. In this study, by using water as support material, we have fabricated the first cellulose-based aerogels having truly 3D geometries with overhang features via the 3D freeze printing method incorporating a drop on demand-based materials deposition approach. The support material was removed from the main structure by a freeze-drying process, which is already a regular step in 3D printing process of aerogels. Fabricated aerogels possessed a highly ordered microstructure, in which the micropores were aligned along the freezing direction. We have investigated the effects of this anisotropy in the mechanical properties of the final aerogels. All the samples exhibited an excellent strain memory effect, and after 100 cyclic compression up to 25% strain, the obtained stress decay values were ~30% and ~16% in axial and radial directions, respectively. We further investigated the cross-linking of the fabricated aerogels to enhance their stability for making them feasible for applications such as biomedical or tissue engineering that requires wet environment. Finally, we functionalized the 3D printed cellulose-based aerogels with PEDOT:PSS, and evaluated their performance in piezoresistive sensing applications.



中文翻译:

3D 冷冻打印纤维素基气凝胶:获得真正的 3D 形状,并使用交联和导电添加剂进行功能化

纤维素是地球上存在的最丰富的天然聚合物,源自纤维素的纳米材料已用于各种应用。基于纤维素纳米材料的气凝胶由于其超低的热导率、模量、声速、折射率、介电常数、高比表面积和可调节的密度而引起了极大的研究兴趣。纤维素基气凝胶的 3D 打印提供了制造具有设计孔形态的复杂几何形状的能力,这对于各种应用都是有利的。然而,由于缺乏可以从结构上移除而无需使用可能影响纤维素材料的苛刻和繁琐的化学/热处理工艺的支撑材料,几何形状的复杂性仍然存在限制。本研究以水为支撑材料,我们已经通过 3D 冷冻打印方法制造了第一个具有真正 3D 几何形状和悬垂特征的基于纤维素的气凝胶,该方法结合了基于需求的材料沉积方法。通过冷冻干燥过程将支撑材料从主体结构上移除,这已经是气凝胶 3D 打印过程中的常规步骤。制造的气凝胶具有高度有序的微观结构,其中微孔沿冻结方向排列。我们已经研究了这种各向异性对最终气凝胶机械性能的影响。所有样品都表现出优异的应变记忆效应,经过 100 次循环压缩达到 25% 应变后,获得的轴向和径向应力衰减值分别为~30% 和~16%。我们进一步研究了制造的气凝胶的交联,以提高它们的稳定性,使其适用于需要潮湿环境的生物医学或组织工程等应用。最后,我们用 PEDOT:PSS 对 3D 打印的纤维素基气凝胶进行了功能化,并评估了它们在压阻传感应用中的性能。

更新日期:2021-06-07
down
wechat
bug