木质素复合氧化石墨烯导电水凝胶制备及性能

Preparation and properties of conductive hydrogels derived from lignin-graphene oxide composite

生物质基新型导电水凝胶材料在生物电子应用领域显示出广阔的应用前景。采用经典的双网络水凝胶构建策略,通过“一锅煮”的方法,引入具有较为优异导电性能的氧化石墨烯(GO),在水溶液体系中通过聚合和交联反应设计制备具有导电性能的木质素磺酸钠/聚丙烯酰胺/氧化石墨烯(LS/PAM/GO)复合水凝胶。由于双层高分子网络互穿作用和大分子间以及网络间氢键相互作用力,所得的复合水凝胶表现出较强的机械性能和自恢复性能,并通过红外光谱分析、扫描电子显微镜和万能试验机等对复合水凝胶的结构和性能进行了表征。研究结果表明:GO的添加显著影响了复合水凝胶的拉伸和压缩性能,当GO质量分数为6.1%时,材料的最大拉伸强度达到最大值421 kPa,与此对应的断裂伸长率达到483%;当材料的压缩强度在其应变为90%时可达到5.82 MPa。LS/PAM/GO复合水凝胶呈明显的多孔状立体网络结构,孔分布较均匀。复合水凝胶导电性能随GO含量增加而提高,GO质量分数为6.1%时,复合水凝胶电导率为0.0317 S/m,在压缩、拉伸过程中凝胶材料的电信号表现出明显的规律性,因此该水凝胶在柔性电子器件方面具有潜在的应用价值。

New biomass-based conductive hydrogel materials show broad application prospects in the field of bioelectronics. Although many researchers have reported that the addition of conductive materials to biologically based hydrogels could improve the conductivity, the lack of flexibility and conductivity is still a bottleneck problem in the research field of biologically based conductive hydrogels. In order to promote the practical application of hydrogels and overcome the problems of poor mechanical properties, researchers proposed construction strategies such as double network(two networks with different properties), and synthesized hydrogels with various three-dimensional network structures such as topological structure and interpenetrating/semi-interpenetrating network structure. In this work, the classical double network hydrogel construction strategy, namely “one pot” method, using sodium lignosulfonate(LS), acrylamide(AM), go as raw materials(GO), polyethylene glycol diglygde(PEGDGE), N,N′-methylene bisacrylamide(MBA) as crosslinking agent, and ammonium persulfate(APS) as initiator were applied to prepare the sodium lignosulfonate/polyacrylamide/GO(LS/PAM/GO) composite hydrogels with good conductive properties by the polymerization and crosslinking reaction in the aqueous solution. The first network is composed of LS network, which contains a large number of phenolic hydroxyl groups and can react with PEGDGE to form a large network structure. The second network layer is the PAM network crosslinking layer. Due to the interaction of the double-layer polymer network and hydrogen bond interaction between macromolecules and networks, the composite hydrogels showed strong mechanical properties and self-recovery properties. The structure and properties of the composite hydrogels were characterized by the Fourier transform infrared spectrometer(FT-IR), scanning electron microscope(SEM), and universal tensile machine. The results showed that the addition of GO significantly affected the tensile and compressive properties of composite hydrogels. When the GO mass fraction was 6.1%, the maximum tensile strength reached 421 kPa, and the corresponding elongation at break reached 483%. The material’s compressive strength can reach 5.82 MPa when the strain was 90%. The LS/PAM/GO composite hydrogels showed obvious porous stereoscopic network structure and the pore distribution was uniform. The conductivity of the composite hydrogel increased with the increase of GO content. When the GO mass fraction was 6.1%, the conductivity of the composite hydrogel was 0.031 7 S/m. The electrical signals of the gel material show obvious regularity in the process of compression and stretching, so the hydrogel has potential application value in flexible electronic devices.