Conductive Ti3C2Tx MXenes have been widely investigated for the construction of flexible and highly‐sensitive pressure sensors. Although the inevitable oxidation of solution‐processed MXene has been recognized, the effect of the irreversible oxidation of MXene on its electrical conductivity and sensing properties is yet to be understood. Herein, we construct a highly‐sensitive and degradable piezoresistive pressure sensor by coating Ti3C2Tx MXene flakes with different degrees of in situ oxidation onto paper substrates using the dipping‐drying method. In situ oxidation can tune the intrinsic resistance and expand the interlayer distance of MXene nanosheets. The partially oxidized MXene‐based piezoresistive pressure sensor exhibits a high sensitivity of 28.43 kPa−1, which is greater than those of pristine MXene, over‐oxidized MXene, and state‐of‐the‐art paper‐based pressure sensors. Additionally, these sensors exhibit a short response time of 98.3 ms, good durability over 5000 measurement cycles, and a low force detection limit of 0.8 Pa. Moreover, MXene‐based sensing elements are easily degraded and environmentally friendly. The MXene‐based pressure sensor shows promise for practical applications in tracking body movements, sports coaching, remote health monitoring, and human–computer interactions.

Chemically exfoliated nanosheets have been extensively employed as functional nanofillers for the fabrication of polymer nanocomposites due to their remarkable electrical, magnetic and optical properties. However, achieving a good dispersion of charged nanosheets in polymer matrix, which will determine the performance of polymer nanocomposites, remains a challenge. Herein, we investigated the dispersion and aggregation behavior of negatively charged Ca2Nb3O10 (CNO) perovskite nanosheets in negatively charged sodium alginate (SA) aqueous dispersion using dynamic light scattering (DLS). When CNO nanosheets meet with SA, aggregation and coagulation inevitably occurred owing to the absorption of SA on nanosheets. By controlling the electrostatic attraction between positively charged poly(ethylene imine) (PEI) and negatively charged SA, the charge density and hydrodynamic size of SA can be tuned to enable the good dispersion of CNO nanosheets in SA. This result may provide a new strategy to achieve the good dispersion of charged nanosheets in charged polymers for the rational design of multifunctional nanocomposites.