Preparation of flexible pressure sensor based on MXene/PEDOT:PSS and its application in lip language recognition
Lip language is an effective form of verbal communication for patients with vocal cord injuries,laryngeal and tongue injuries,and hearing loss.Lip-speaking signals are generated by lip and facial muscle movements,which contain a large amount of speech information.The extraction and recognition of lip-speaking signals can be achieved by capturing the muscle movements through flexible pressure sensors,providing a more natural and convenient way of accessible communication for patients with listening and speaking dysfunction.In this study,a piezoresistive flexible pressure sensor was prepared using a two-dimensional material,MXene,and a highly conductive polymer,poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS),as composites,and a stretchable and microstructured ecoflex as a flexible substrate.The piezoresistive sensor demonstrates a high sensitivity of 42.31 kPa-1 and fast response(<150 ms)in the pressure range of 0-2.5 kPa,and shows high stability in 10 000 compression-release cycles.The flexible piezoresistive sensor was attached to the corners of the mouth and captured the muscle movements of the lips,which was combined with a convolutional neural network algorithm to train and test the signals of English words in the Chinese zodiac,with an average accuracy of up to 90.18%.This work increases the versatility of lip recognition systems and lays an important foundation for the direct conversion of lip movement signals into speech or text.