Fine structural tuning of fluorescent copolymer sensors for methamphetamine vapor detection

Fluorescent sensors with high sensitivity, selectivity and fast response for trace detection of methamphetamine (MA) have been rarely reported. Herein, three fluorene-based sensory materials were synthesized and used for MA detection. The fine structural tuning could control both the energy level and bonding force to MA. Their fluorescence quenching responses to different amines were due to photo-induced electron transfer (PET) from MA donor to the photoexcited state of sensing polymers. Meanwhile, the fine-tuning of the bonding force resulted in different sensitivity and selectivity of the polymers. Among them, polymer with benzothiadiazole showed the best selectivity and sensitivity to MA vapor with a detection limit of 180 ppb. And ∼20% fluorescence could be quenched/recovered within 2 s upon exposure to MA and air in sequence.