Photonic materials that enable visual detection of chemicals have shown great potential for wide applications in chemical, environmental, biotechnological, and food industries, but until now, using hydrophilic photonic materials for tracing water-soluble chemicals remains a major challenge due to the strong water interference. Here, we demonstrate a two-step co-assembly and subsequent surface coating strategy to develop an ethanol-sensitive and anti-water interference photonic crystal film. By using citric acid as a co-assembly phase, high ethanol sensing is realized because of the strong intermolecular affinity. By controlling the thickness of the outer polyvinyl butyral layer, selective ethanol penetration but a water barrier is enabled. Notably, the composite photonic films are free-standing, highly flexible, and controllably structurally colored. We further present using the composite film to quantitatively trace ethanol/water mixtures and potentially track drunk driving as a colorimetric sensor. The heuristic two-step modification strategy proposed in this work not only overcomes the limitation of water interference for hydrophilic colorimetric sensors but also provides references to develop more new photonic materials with water resistance that need to be applied in water/humid environments.

中文翻译：

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一种用于准确检测乙醇的防水光子材料的表面扩散屏障策略

能够对化学物质进行视觉检测的光子材料在化学、环境、生物技术和食品工业中显示出巨大的应用潜力，但直到现在，由于强水干扰，使用亲水性光子材料来追踪水溶性化学物质仍然是一项重大挑战. 在这里，我们展示了一种两步共组装和随后的表面涂层策略，以开发乙醇敏感和抗水干涉光子晶体薄膜。通过使用柠檬酸作为共组装相，由于分子间亲和力强，实现了高乙醇传感。通过控制聚乙烯醇缩丁醛外层的厚度，可以实现选择性乙醇渗透但防水层。值得注意的是，复合光子薄膜是独立的，高度灵活的，和可控的结构着色。我们进一步提出使用复合膜定量追踪乙醇/水混合物，并可能跟踪酒后驾驶作为比色传感器。该工作提出的启发式两步修改策略不仅克服了亲水比色传感器的水干扰限制，而且为开发更多需要在水/潮湿环境中应用的具有防水性的新型光子材料提供了参考。