Chemical Information Conversion System by Using Hydrogel-Modified Ultramicroelectrodes

使用水凝胶修饰超微电极的化学信息转换系统

• 批准号: 04650813
• 负责人: WATANABE Masayoshi
• 金额: $ 0.58万
• 依托单位: Yokohama National University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1993
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04650813/
• 关键词: Hydrogel; Volume-Phase Transition; Ultramicroelectrode; Modified Electrode; Swelling Ratio; Redox Reaction; Polyacrylamide; Poly(N-isopropyl acrylamide); 拡散係数; 分配係数; 化学情報変換; Hydrogel; Volume-Phase Transition; Ultramicroelectrode; Modified Electrode; Swelling Ratio; Redox Reaction; Polyacrylamide; Poly(N-isopropyl acrylamide); 拡散係数; 分配係数; 化学情報変換

Hydrogels, such as poly(N-isopropyl acrylamide) and polyacrylamide, have been successfully moified onto the surface of Pt ultramicroelectrodes. The chemical modification has been established by the introduction of vinyl group onto the electrode surface, followed by the synthesis of the gels on the electrode surface. These gel-modified electrodes, where the shape of the gel is hemispherical in the swollen state, were immersed in aqueous solutions containing redox molecules, and electrochemical measurements were conducted. The chemical modification of the gels on the electrode surface allowed to conduct electrochemical measurements both in the swollen and shrunken states of the gels, and further in the transition states of swelling, i.e., from the swollen to shrunken states and vice versa. Independent determination of of the concentration and diffusion coefficient of the redox molecules inside the gels has been achieved by exploiting electrochemical methods both in equilibrated and trans … More ient state of swelling. This provides a new methodology to study micro-environment and dynamics of hydrogels, and at the same time, to convert large swelling change of hydrogels, including the volume-phase transition, to electric signal.In poly(N-isopropyl acrylamide)(PNIPAAm) gels, reaching equilibrated swelling, the concentration and diffusivity of redox molecule, [Ru(NH_3)_6]Cl_3, indide the gels were not so different from those of the outside solution in the swollen state, whereas considerable condensation and suppression in the diffusivity of the complex were found in the shrunken gels.For polyacrylamide(PAAm) gels, the measurements not only in the equilibrated state but also in the transient state of swelling were conducted by using N-ferrocenylmethyl-N, N, N-trimethylammonium hexafluorophosphate (Fc) as a redox molecule. The transient electrolytic current vs time(i-t) curves measured in the shrinking process, where the gel was immersed into acetone from water, revealed the following facts :1) The i-t curve showed a peak at a certain time, instead of simple decreasing.2) A smaller size gel showed the peak at earlier time than a larger size gel, and the peak time was directly proportional to the square of the radius of the gel in water.3) The peak current increased with decreasing the radius of the gel in water.Mechanism for these results has been analyzed, taking into consideration the dynamics and spatial inhomogeneity of the gels in the shrinking process. Less

水凝胶，例如聚（N-异丙基丙烯酰胺）和聚丙烯酰胺，已成功地置于PT超核电极的表面上。通过将乙烯基群引入电极表面，然后在电极表面合成凝胶，从而确定了化学修饰。将这些凝胶改性的电极浸入含有氧化还原分子的水溶液中，并进行了电化学测量。电极表面上凝胶的化学修饰允许在凝胶肿胀和缩小状态下进行电化学测量，以及在肿胀的过渡状态，即从肿胀到缩水到缩水状态，反之亦然。通过利用等效和反式的电化学方法来实现氧化还原分子的浓度和扩散系数的独立测定。这提供了一种新的方法来研究水凝胶的微环境和动态，同时，将水凝胶的肿胀变化（包括体积过渡）转化为电信号。 gels were not so Different from those of the outside solution in the swollen state, whereas considerable condensation and suppression in the difficulty of the complex were found in the shrunken gels.For polyacrylamide(PAAm) gels, the measurements not only in the equivalent state but also in the transient state of swolling were conducted by using N-ferrocenylmethyl-N, N, N-trimethyllammonium六氟磷酸盐（FC）作为氧化还原分子。在缩小过程中测得的瞬时电解电流与时间（I-T）曲线，在缩小过程中，凝胶从水中浸入丙酮中，揭示了以下事实：1）I-T曲线在特定时间显示出峰值，而不是简单的减小，而不是简单的减小。2）较小的凝胶在较早的时间上显示出比较大的峰值凝胶的峰值，凝胶的峰值均与较大的峰值相比，凝胶是凝胶的范围，凝胶是凝胶的范围。考虑到凝胶在收缩过程中凝胶的动力学和空间不均匀性，分析了这些结果的机制。较少的