Research On Flexible Multi-claw And Multi-channel EEG Semi-dry Electrodes Based On Cu-TiO₂-CNT@PDMS

With the deepening of brain research,EEG(Electroencephalograph,EEG)acquisition technology continues to develop and is used in various aspects such as brain-computer interface,medical diagnosis,and medical treatment.In the existing acquisition technology,the wet electrode is complicated to operate and is not suitable for long-term EEG monitoring,and the dry electrode has high hardness,large impedance and poor signal quality.Aiming at the shortcomings of the existing EEG collection technology,this paper designs and prepares a flexible multi-jaw semi-dry electrode and a 19-channel semi-dry electrode based on the Cu-TiO₂-CNT@PDMS matrix.The flexible substrate sensitive film of the electrode is made of copper sulfate crystals,TiO₂nanoparticles,and a mixture of carbon nanotubes(CNTs)and polydimethylsiloxane(PDMS).The flexible Cu-TiO₂-CNT@PDMS substrate not only improved the bonding and comfort on the scalp,but also enabled the internal CNT conductive network to quickly transmit the electron current.The scalp-contact impedance of the flexible matrix was<5 k?when coated with conductive gel,whereas the poured semi-dry electrodes were<20 k?in the hair area.The correlation coefficient between the spontaneous EEG signals synchronously collected by commercial Ag/Ag Cl and the semi-dry electrodes was greater than 99.3%.With these flexible electrodes,the amplitude of the?-rhythm reached 6?V in the frequency domain,the service life was more than 3 months,and the SNR of the EEG signal reached 8–12 d B in steady-state visual evoked potential.For the 19-channel high-density electrode,the real-time EEG impedance of each channel was<26.3 k?,and the SNR of the EEG at rest was 6.3 d B.The high-density electrode showed the response of?-and?-rhythms in auditory evoked EEG,and the regularity of these two rhythms was extracted from feedback EEG signals of speech and semantic stimuli.The Cu-TiO₂-CNT@PDMS matrix and its semi-dry electrodes provide new materials and new processes for the preparation of flexible semi-dry electrodes and offer a new strategy for the preparation of integrated high-density electrodes.