受肌肉启发的离子响应韧性可调型水凝胶的开发与应用

Muscle-inspired ion-sensitive hydrogels with highly tunable mechanical performance for versatile industrial applications

肌肉组织可因特定离子的刺激而发生显著机械性能的变化.受此现象启发,本文通过一种简单高效的策略,赋予结晶型聚乙烯醇水凝胶显著的盐响应性特征.与肌肉组织类似,这类水凝胶的机械性能展现出强烈的离子种类及浓度的依赖关系.经过相关浓度盐溶液处理后,该水凝胶在硬度(杨氏模量~0.16-9.6 MPa)、延展性(伸长率~100%-570%)和韧性(断裂功~0.82-35 MJm^(-3))方面表现出大范围的可调控性.其机械性能的变化很好地遵循了霍夫迈斯特序列,即强盐析性质的离子(kosmotropes)在水凝胶增韧中彰明较著.同时,该水凝胶的机械性能与盐溶液浓度表现出显著的正相关性.实验证明,离子可显著影响非晶区的高分子水化程度和结晶区的聚合物结晶度,进而协同调控水凝胶的机械性能.得益于此,这类水凝胶在韧性可调工程软材料、防冰涂料和柔性电子设备等领域展现出良好的应用前景.

Human muscles are notably toughened or softened with specific inorganic ions.Inspired by this phenomenon,herein we report a simple strategy to endow hydrogels with comparable ion-responsive mechanical properties by treating the gels with different ionic solutions.Semi-crystalline poly(vinyl alcohol)hydrogels are chosen as examples to illustrate this concept.Similar to muscles,the mechanical property of hydrogels demonstrates strong dependence on both the nature and concentration of inorganic ions.Immersed at the same salt concentration,the hydrogels treated with different ionic solutions manifest a broad-range tunability in rigidity(Young’s modulus from 0.16 to 9.6 MPa),extensibility(elongation ratio from 100% to 570%),and toughness(fracture work from 0.82 to 35 MJm^(-3)).The mechanical property well follows the Hofmeister series,where the“salting-out”salts(kosmotropes)have a more pronounced effect on the reinforcement of the hydrogels.Besides,the hydrogels’mechanical performance exhibits a positive correlation with the salt concentration.Furthermore,it is revealed both the polymer solubility from amorphous domains and polymer crystallinity from crystalline domains are significantly influenced by the ions,which synergistically contribute to the salt-responsive mechanical performance.Benefitting from this feature,the hydrogels have demonstrated promising industrial applications,including tunable tough engineering soft materials,anti-icing coatings,and soft electronic devices.