Abstract

The organic UVA filter is popularized in sunscreen cosmetics due to the advantages of excellent light stability and high molar extinction coefficient. However, the poor water solubility of organic UV filters has been a common problem. Given that nanoparticles (NPs) can significantly improve the water solubility of organic chemicals. Meanwhile, the excited-state relaxation pathways of NPs might differ from their solution. Here, the NPs of diethylamino hydroxybenzoyl hexyl benzoate (DHHB), a popular organic UVA filter, were prepared by an advanced ultrasonic micro-flow reactor. The surfactant (sodium dodecyl sulfate) was selected as an effective stabilizer to prevent the self-aggregation of the NPs for DHHB. Femtosecond transient ultrafast spectroscopy (fs-TA) and theoretical calculations were utilized to trace and explain the excited-state evolution of DHHB in NPs suspension and its solution. The results reveal that the surfactant-stabilized NPs of DHHB reserve a similarly good performance of ultrafast excited-state relaxation. The stability characterization experiments demonstrate that the strategy of surfactant-stabilized NPs for sunscreen chemicals can maintain its stability and enhance the water solubility of DHHB compared with that of the solution phase. Therefore, the surfactant-stabilized NPs of organic UV filters are an effective method to improve water solubility and keep the stability from aggregation and photoexcitation.

Graphical Abstract

中文翻译：

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二乙氨基羟基苯甲酰基苯甲酸己酯（DHHB）通过纳米粒子的超快激发态能量耗散途径

摘要

有机UVA滤光剂因其优异的光稳定性和高摩尔消光系数的优点而在防晒化妆品中得到普及。然而，有机紫外线过滤剂的水溶性差一直是一个普遍的问题。鉴于纳米颗粒（NP）可以显着提高有机化学品的水溶性。同时，纳米粒子的激发态弛豫路径可能与其溶液不同。在这里，二乙氨基羟基苯甲酰基苯甲酸己酯 (DHHB)（一种流行的有机 UVA 过滤剂）的纳米颗粒是通过先进的超声波微流反应器制备的。选择表面活性剂（十二烷基硫酸钠）作为有效的稳定剂，以防止 DHHB 纳米颗粒的自聚集。利用飞秒瞬态超快光谱（fs-TA）和理论计算来追踪和解释 DHHB 在纳米粒子悬浮液及其溶液中的激发态演化。结果表明，表面活性剂稳定的 DHHB 纳米粒子保留了同样良好的超快激发态弛豫性能。稳定性表征实验表明，与溶液相相比，表面活性剂稳定的纳米粒子用于防晒化学品的策略可以保持其稳定性并提高DHHB的水溶性。因此，有机紫外线过滤剂的表面活性剂稳定的纳米粒子是提高水溶性并保持聚集和光激发稳定性的有效方法。

图形概要