Rigid and Strong Thermoresponsive Shape Memory Hydrogels Transformed from Poly(vinylpyrrolidone-co-acryloxy acetophenone) Organogels

Abstract

Shape memory hydrogels (SMHs) have a wide range of potential practical applications. However, the mechanically weak and soft nature of most SMHs strongly impedes their applications. Here, we report a novel kind of thermal-responsive SMH with high tensile strength and high elastic moduli. Organogels are first prepared by the copolymerization of a hydrophilic monomer N-vinylpyrrolidone (NVP) and a hydrophobic monomer acryloxy acetophenone (AAP) in N, N'-dimethylformamide (DMF) solutions, and then, poly(vinylpyrrolidone- co-acryloxy acetophenone) [poly(NVP- co-AAP)] hydrogels are obtained by solvent exchange with water. Because of the strong and reversible hydrophobic association and π-π stacking of acetophenone groups, the poly(NVP- co-AAP) hydrogels exhibit tensile strengths up to 8.41 ± 0.83 MPa and Young's moduli up to 94.2 ± 1.3 MPa, which are more than 1 or 3 orders of magnitude higher than those of the organogels, respectively. The poly(NVP- co-AAP) hydrogels exhibit good shape memory behaviors, with a complete fixation ratio and a recovery ratio of 74-89%, as well as very fast shape-fixing and recovering rates (in seconds). These rigid and strong hydrogels are demonstrated to be an ideal shape memory material for surgical fixation devices to wrap around and support various shapes of limbs.

Cation-induced shape programming and morphing in protein-based hydrogels

“…S2). These values are comparable with those measured for BSA hydrogels programmed with polyethylenimine (19) and with other polymeric materials using double network or polymer-ion interactions (37). As shown in Fig.…”

Research progress of radiation synthesis and application of hydrogels

“…另外, 由于AgNPs在伤口敷 料中具有抗炎杀菌的作用, Alcântara等 [46] 通过辐射法 制备了两种含有AgNPs的水凝胶(PVP/AgNPs和PVA/ AgNPs), 在辐照过程中, Ag + 还原形成纳米粒子, 图 13 豆苗在不含SAH水凝胶(a)及含SAH水凝胶(b)情况 下的生长情况 [11] (网络版彩图) Figure 13 The growth of bean seedlings without SAH hydrogel (a) and with SAH hydrogel (b) [11] (color online). [59] 、人造皮肤 [60,61] 、生物分子、细胞的固定 图 14 聚(NVP-co-AAP)水凝胶作为指关节(a)、手腕(b)、腿和脚(c)的固定支撑材料 [23] (网络版彩图) 图 15 Li 2 SO 4 -AG/PAM 双网络水凝胶的辐射合成及在超级 电容器中的应用 [65] (网络版彩图) Figure 15 Radiation synthesis process of the Li 2 SO 4 -AG/PAM double network hydrogel electrolytes and its application in supercapacitors [65] (color online).…”

“…(2) 当体系中引入纳米粒子时, 通过高能射线辐照 (1) 反应物为一元或多元单体, 通过辐射引发单体 聚合、交联制备水凝胶. Zhai等 [19] 图 3 两亲性PMADAB凝胶的辐射合成路线图 [20] (网络版 彩图) (b) 聚(NVP-co-AAP)有机凝胶和聚(NVP-co-AAP)水凝胶的 辐射合成方法和形成机理示意图 [23] (网络版彩图) 图 5 纳米复合水凝胶的辐射合成示意图 [24] (网络版彩图) 图 6 PAAm-MWNT纳米复合水凝胶的合成示意图 [25] (网 络版彩图) Figure 6 The fabrication process for the nanocomposite hydrogels of PAAm-MWNT [25] (color online).…”

“…Demonstration of the application of poly(NVP-co-AAP) hydrogels as gypsum substitutes to wrap around and support different limbs, including (a) knuckle, (b) wrist, and (c) shank and foot[23] (color online).…”

Combinational Hydrogel and Xerogel Actuators Showing NIR Manipulating Complex Actions

“…The recovery from temporary shape to original shape under stimuli makes the shape memory hydrogels receive wide attention in soft actuators and drug delivery fields . Most shape memory hydrogels contain two or more networks, including chemically crosslinked permanent network and various physically crosslinked reversible networks . This feature results in that the preparation and composition of the shape memory hydrogels are often complex in order to manufacture these complicated networks.…”