Hydrophobically associated hydrogels based on acrylamide and anionic surface active monomer with high mechanical strength
作者:Wenbo Li、Huiyong An、Ying Tan、Cuige Lu、Chang Liu、Pengchong Li、Kun Xu、Pixin Wang
DOI:10.1039/c2sm07200a
日期:——
In this work, a physically cross-linked hydrogel (HA gels) with high mechanical strength is synthesized via micellar copolymerization of acrylamide (AAm) and an anionic surface active monomer (surfmer), sodium 9 or 10-acrylamidostearic acid (NaAAS) without any adscititious surfactant or chemical cross-linkers. SEM and DLS characterizations indicate that the surfmer formed multi-micellar aggregates with 80–90 nm diameters above its critical micelle concentration, and serve as a crosslinked-center to endow the obtained hydrogel a robust three-dimensional architecture. Compared with the chemically cross-linked hydrogel, HA gels exhibit unusual swelling–deswelling behavior in water and a pulsatile swelling–deswelling behavior is exhibited with alternating pH changes from 5 to 10 because the presence of carboxyl in the surfmer, demonstrating a smart characteristic of the hydrogel. Moreover, the presence of the surfmer greatly improve the mechanical properties of HA gels. A hydrogel containing 20% (mol/mol) surfmer shows a compression strength of 22.50 MPa at a strain of 90% and can be elongated to 13 times its original length. Furthermore, the HA gels show a significant hysteresis recovery after large deformation, underlying a serious energy-dissipation mechanism. This uncommon swelling behavior and mechanical properties of the HA gels result from its special characteristic of cross-linked units. A self-healing ability is expected for this physical hydrogel in future applications in biotechnology.
在这项工作中,通过丙烯酰胺(AAm)和阴离子表面活性单体(surfmer)、9或10-丙烯酰胺硬脂酸钠(NaAAS)的胶束共聚合成了一种具有高机械强度的物理交联水凝胶(HA凝胶),不含任何添加剂。外加表面活性剂或化学交联剂。 SEM 和 DLS 表征表明,冲浪者形成了直径高于其临界胶束浓度 80-90 nm 的多胶束聚集体,并作为交联中心赋予所获得的水凝胶坚固的三维结构。与化学交联水凝胶相比,HA凝胶在水中表现出不寻常的溶胀-消溶胀行为,并且由于冲浪者中羧基的存在,随着pH值从5到10交替变化,呈现出脉动溶胀-消溶胀行为,表现出一种智能特征水凝胶。此外,冲浪者的存在大大提高了HA凝胶的机械性能。含有 20% (mol/mol) surfmer 的水凝胶在 90% 应变下表现出 22.50 MPa 的压缩强度,并且可以伸长至其原始长度的 13 倍。此外,HA凝胶在大变形后表现出显着的滞后恢复,这是严重的能量耗散机制的基础。 HA 凝胶这种不寻常的溶胀行为和机械性能源于其交联单元的特殊特性。这种物理水凝胶有望在未来的生物技术应用中具有自愈能力。