智能凝胶颗粒几何修饰大孔电极及其电化学传感行为

Macroporous electrodes with large specific surface activation area and high porosity ratio allow not only the adequately efficient in charge transfer and mass transport of electroactive species at electrode surface, but also functionalized modification of the surface through various methods. Thus, the preparation and surface modification of macroporous electrodes have been one of the major research focus in the development of new electrochemical sensors. In this research, colloidal crystal films of polystyrene/poly(acrylic acid) particles are used as sacrificial template. Pt and Au are electrodeposited into the interstitial spaces of close packed array of latex particles to fabricate a spherical macroporous electrode. Due to the reversible swelling and de-swelling properties of intelligent gel particles, poly(acrylic acid) based gel particles are geometrically loaded into the cavities of the electrode by controlling their size. Electrochemical methods such as cyclic voltammetry and differential pulse voltammetry are useful to determine the dissociation kinetics of the carboxyl groups by controlling solution temperature, pH and ionic strength. Dopamine, luteolin and para-aminophenol are chose as biological, medical and environmental sample solutions to investigate the electrochemical sensorial behaviors of the modified macroporous electrode. Large amount of carboxyl groups are exist in the network of the gel particles. Therefore, the local surface pH of the electrode will be controlled to weak acid condition through dissociation equilibrium of the carboxyl groups. Furthermore, the gel particle can also works as a continuous proton source for proton-coupled electron transfer reactions. The modified macroporous electrodes are expected to be useful for in-situ determination of phenol, quinone and flavone derivative samples. Research on electrochemical sensorial behaviors of the gel particles geometrically modified macroporous electrode will further expand the scope of the application of polymer microparticles in electrochemical device. This will also provide the theoretical foundation and technical support for the new design and development of electrochemical sensors.

具有大活性比表面积和高孔隙率的大孔电极，既能有效促进电活性物质及电子在电极表面的传输，又易于进行多种方式的表面功能化修饰，其制备与修饰已成为开发新型电化学传感器的主要研究热点之一。本研究以聚苯乙烯/聚丙烯酸微球晶体膜为牺牲模板，电沉积制备球腔型大孔Au和Pt电极，并利用智能凝胶颗粒的收缩/溶胀特性，将聚丙烯酸凝胶颗粒几何固定于电极球腔内部，使其与电极完美结合。运用循环伏安、微分脉冲伏安等电化学方法，探讨温度、pH及离子强度对羧基解离动力学影响，并分别在以多巴胺、木犀草素、对氨基苯酚为代表的生物、医药和环境样品中，进行电极电化学传感行为研究。凝胶网络中大量存在的羧基通过解离平衡，能将电极近表面pH控制在弱酸性环境，为质子参与型反应持续提供质子，有望实现酚类、醌类及酮类衍生物的现场测量。本研究有助于进一步促进高分子微球在电化学领域的应用，并为新型电化学传感器的设计开发提供理论依据和技术支持。

本研究以聚苯乙烯/聚丙烯酸微球晶体膜为牺牲模板，电沉积制备了球腔型三维有序大孔Pt和Au电极，并利用智能凝胶颗粒的收缩/溶胀特性，将聚丙烯酸（NIPA/AA）凝胶颗粒几何固定于电极球腔内部，制得凝胶颗粒几何修饰大孔电极。大孔电极球腔尺寸及结构，可通过调节模板微球粒径和沉积电量精确控制。由于较高的孔隙率和较大的电活性面积，大孔电极能有效促进电活性物质及电子在电极表面的传输。然而，对于受扩散控制的电极反应过程，球腔型三维有序大孔电极因相邻球腔之间扩散层相互重叠，而表现出与平面电极相似的电化学行为。修饰在电极表面的NIPA/AA凝胶颗粒，即使在中性条件也能得到很强的H+还原电流，电流大小与所修饰的凝胶颗粒数量成正比，且受扩散、吸附及解离协同控制。凝胶网络中大量存在的羧基通过解离平衡，能将电极近表面pH控制在弱酸性环境，并为质子参与型反应持续提供质子。因此，NIPA/AA凝胶颗粒修饰电极能在没有缓冲液的条件下，实现多巴胺、木犀草素、对氨基苯酚、对乙酰氨基苯酚、抗坏血酸和尿酸等物质在实际样品中的稳定检测。. 在该项目研究过程中，项目主持人先后在Talanta, Lab on a Chip，Biosensors and Bioelectronics，Analytical Chemistry等期刊发表学术论文11篇（SCI 10篇，北大中卫核心期刊1篇），其中3篇SCI论文在本项目的资助下完成；获批国家专利1项；获陕西省科学技术二等奖1项；参加学术会议1次；协助培养研究生5名（其中博士1名，硕士4名）。