A bicontinuous microemulsion system consisting of sodium bis(2-ethylhexyl) sulfosuccinate (AOT), sodium dodecylsulfate (SDS), an aqueous solution (a 0.1 M disodium hydrogenphosphate/citric acid buffer solution of pH = 4.3), and decane was investigated in detail for applications as reaction medium for the horseradish peroxidase (HRP)/hydrogen peroxide-mediated synthesis of the conductive form of polyaniline (PANI). To formulate the optimal single-phase microemulsion with the phase inversion temperature being close to room temperature, the T-γ fishlike phase diagram of the AOT/SDS-buffer-decane pseudoternary system was determined. The effects of the surfactant concentration (γ), the oil-to-water ratio (α) and the temperature (T) on the conductivity of the resulting PANI and the underlying mechanism were investigated using UV–vis-NIR, ESR and small-angle X-ray scattering (SAXS) techniques. Results show that the bicontinuous microemulsion plays a template role in the PANI biosynthesis, and the PANI conductivity also depends on the activity and stability of the solubilized HRP, which are determined by the microdomain size of the microemulsions and the reaction temperature. As far as γ is concerned, it is found that as γ increases, the microdomain size of the bicontinuous microemulsion as well as the activity of the solubilized HRP decreases significantly, leading to a great decrease of the PANI conductivity. Compared with γ, the change of α has small effect on the PANI conductivity. As the α-dependent microdomain size changes little with increasing α, the small change of the PANI conductivity should be ascribed mainly to the HRP activity. For T, over the range of 20 °C–35 °C, it has a slight effect on the microdomain size of the bicontinuous microemulsion, but it has a marked effect on the enzymatic properties of HRP. As the temperature increases, the activity of HRP increases, but its thermal stability decreases greatly. Therefore, the thermal stability of HRP is the major factor causing that the PANI conductivity decreases significantly with increasing T. The present work deepens the understanding of the template effect of anionic surfactant aggregates in the biosynthesis of conducting PANI. To the best of our knowledge, this work is the first study of the use of bicontinuous microemulsions as reaction media for the enzymatic synthesis of a conducting polymer.

详细研究了由双（2-乙基己基）磺基琥珀酸钠（AOT），十二烷基硫酸钠（SDS），水溶液（pH = 4.3的0.1 M磷酸氢二钠/柠檬酸缓冲溶液）和癸烷组成的双连续微乳液体系。用作辣根过氧化物酶（HRP）/过氧化氢介导的聚苯胺（PANI）导电形式合成的反应介质。为了制备相转化温度接近室温的最佳单相微乳液，确定了AOT / SDS-缓冲-癸烷假三元体系的T - γ鱼状相图。表面活性剂浓度（γ），油水比（α）和温度（T）对所得PANI的电导率及其潜在机理的研究使用了UV-vis-NIR，ESR和小角X射线散射（SAXS）技术。结果表明，双连续微乳液在PANI生物合成中起模板作用，而PANI的电导率还取决于可溶HRP的活性和稳定性，这取决于微乳液的微区尺寸和反应温度。就γ而言，发现随着γ的增加，双连续微乳液的微区尺寸以及所溶解的HRP的活性显着降低，从而导致PANI电导率大大降低。与γ相比，α的变化对PANI电导率的影响很小。由于α依赖性微区的大小随α的增加而变化很小，因此PANI电导率的小变化应主要归因于HRP活性。对于T，在20°C–35°C的范围内，它对双连续微乳液的微区尺寸有轻微影响，但对HRP的酶学性质有显着影响。随着温度的升高，HRP的活性增加，但其热稳定性大大降低。因此，HRP的热稳定性是导致PANI电导率随T值显着降低的主要因素。。本工作加深了对阴离子表面活性剂聚集体在导电PANI生物合成中模板作用的理解。据我们所知，这项工作是首次使用双连续微乳液作为反应介质进行酶促合成导电聚合物的研究。