Carbon dioxide (CO₂) gas sensing and monitoring have gained prominence for applications such as smart food packaging, environmental monitoring of greenhouse gases, and medical diagnostic tests. Although CO₂ sensors based on metal oxide semiconductors are readily available, they often suffer from limitations such as high operating temperatures (>250 °C), limited response at elevated humidity levels (>60% RH), bulkiness, and limited selectivity. In this study, we designed a chemiresistive sensor for CO₂ detection to overcome these problems. The sensing material of this sensor consists of a CO₂ switchable polymer based on N-3-(dimethylamino)propyl methacrylamide (DMAPMAm) and methoxyethyl methacrylate (MEMA) [P(D-co-M)], and diethylamine. The designed sensor has a detection range for CO₂ between 10³ and 10⁶ ppm even at high humidity levels (>80% RH), and it is capable of differentiating ammonia at low concentrations (0.1–5 ppm) from CO₂. The addition of diethylamine improved sensor performance such as selectivity, response/recovery time, and long-term stability. These data demonstrate the potential of using this sensor for the detection of food spoilage.

中文翻译：

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用于增强二氧化碳气体监测的化学电阻传感器

二氧化碳 (CO ₂ ) 气体传感和监测在智能食品包装、温室气体环境监测和医疗诊断测试等应用中受到重视。尽管基于金属氧化物半导体的CO ₂传感器很容易获得，但它们通常受到诸如工作温度高(>250 °C)、高湿度水平下的有限响应(>60% RH)、体积大和选择性有限等限制。在本研究中，我们设计了一种用于CO ₂检测的化学电阻传感器来克服这些问题。该传感器的传感材料由基于N -3-(二甲基氨基)丙基甲基丙烯酰胺(DMAPMAm)和甲基丙烯酸甲氧基乙酯(MEMA) [P(D- co -M)]的CO ₂可转换聚合物和二乙胺组成。即使在高湿度水平（>80% RH）下，所设计的传感器对CO ₂的检测范围也在10 ³和10 ⁶ ppm 之间，并且能够区分低浓度（0.1–5 ppm）的氨和CO ₂。添加二乙胺改善了传感器性能，例如选择性、响应/恢复时间和长期稳定性。这些数据证明了使用该传感器检测食品腐败的潜力。