Volatile Organic Compounds are a cause of concern for human health. It is particularly the case for BTEX compounds (Benzene, Toluene, Ethylbenzene and Xylenes). Gravimetric sensors are good candidates for their detection but they have to be functionalized by a sensitive film to become active. In this work, organosilicate thin films (SiOCH) deposited by plasma enhanced chemical vapor deposition are investigated. This work aims at understanding the role of their chemical composition on gas adsorption and to propose an optimized material for BTEX detection. Through the synthesis and characterization of various SiOCH thin films, the role of hydrophobicity, carbon content and specific chemical bonding is highlighted. This led to an optimized film presenting both high affinity (partition coefficient toward toluene higher than 15000) and rapid temporal response.

挥发性有机化合物是引起人类健康的原因。BTEX化合物（苯，甲苯，乙苯和二甲苯）尤其如此。重量传感器是检测它们的良好选择，但必须通过感光膜对其进行激活才能起作用。在这项工作中，研究了通过等离子体增强化学气相沉积法沉积的有机硅酸盐薄膜（SiOCH）。这项工作旨在了解其化学成分对气体吸附的作用，并提出一种用于BTEX检测的优化材料。通过各种SiOCH薄膜的合成和表征，突出了疏水性，碳含量和特定化学键的作用。