Asadi Vahid, Dolleman Renee, van der Gucht Jasper, Kodger Thomas E
Physical Chemistry and Soft Matter, Wageningen University & Research Stippeneng 4 6708 WE Wageningen The Netherlands
Mater Adv. 2023 Aug 31;4(22):5535-5545. doi: 10.1039/d3ma00335c. eCollection 2023 Nov 13.
Polymer networks containing bottlebrush chains are emerging materials with exceptionally soft and highly tunable mechanical properties. However, such materials have not been extensively implemented in functional processing techniques such as three-dimensional (3D) printing. Here, we introduce a new design of soft and solvent-free polydimethylsiloxane (PDMS)-based thermoplastic elastomer which contains dangling and space-filling bottlebrush chains, featuring a yield stress and a rapid recovery after stress removal; both required for high spatial fidelity 3D printing. The developed material is composed of two copolymers; the main building block is a diblock copolymer with linear polystyrene (PS) block and bottlebrush PDMS block (PS--bbPDMS) while the second component is PS--PDMS--PS triblock, self-assembling to a physical network. This design provides independent tunability of each structural parameter on the molecular level, hence, macroscopic control of the materials' mechanical properties. Multiple self-supportive 3D structures with spanning elements are 3D printed at elevated temperatures using a developed material with a low shear modulus of ' = 3.3 kPa containing 3 : 1 molar ratio of diblock to triblock copolymers without the need for volatile solvent, or post-treatment. This 3D printing compatible design opens new opportunities to utilize the distinctive mechanical properties of bottlebrush materials for applications such as soft tissue scaffolds, sensors, actuators, and soft robots.
含有刷状链的聚合物网络是一类新兴材料，具有异常柔软且高度可调的机械性能。然而，这类材料尚未广泛应用于诸如三维（3D）打印等功能加工技术中。在此，我们介绍一种新型的基于聚二甲基硅氧烷（PDMS）的无溶剂热塑性弹性体设计，它包含悬垂和填充空间的刷状链，具有屈服应力以及应力去除后的快速恢复特性；这两者都是高空间保真度3D打印所必需的。所开发的材料由两种共聚物组成；主要结构单元是一种具有线性聚苯乙烯（PS）嵌段和刷状PDMS嵌段的二嵌段共聚物（PS-bbPDMS），而第二种组分是PS-PDMS-PS三嵌段共聚物，自组装形成物理网络。这种设计在分子水平上提供了对每个结构参数的独立可调性，从而实现对材料机械性能的宏观控制。使用一种低剪切模量为' = 3.3 kPa、包含二嵌段与三嵌段共聚物摩尔比为3:1的所开发材料，在高温下3D打印出具有跨接元素的多个自支撑3D结构，无需挥发性溶剂或后处理。这种与3D打印兼容的设计为利用刷状材料独特的机械性能在软组织支架、传感器、致动器和软机器人等应用中开辟了新机会。
