Study on meso-macroscopic ionic conductivity of hydrogels and construction of prediction model

Abstract

The utilization of hydrogels in biological devices has seen a significant expansion, necessitating a thorough investigation into their conductivity. In this regard, we conducted a comprehensive examination of the impact of crosslinkers on pore radius and distribution. When the crosslinker proportion was augmented by a factor of 10, the pore radius exhibited a reduction of nearly 3.7 times, resulting in a more uniform pore distribution. Notably, our findings indicated a direct proportionality between conductivity and mesoscopic porosity, coupled with an inverse relationship with crosslinking density. To advance our understanding, we proposed an equivalent pore network model that omits considerations of curvature to predict the ionic conductivity of hydrogels. Intriguingly, as the proportion of crosslinker increased, the mesoscopic pores of hydrogels demonstrated a correlation with macroscopic features. Upon comparison with experimental data, the model exhibited a commendable alignment with the observed trends. Through mutual refinement with experimental results, a novel prediction equation emerged, yielding an average prediction error less than 2%. Beyond trend prediction, our model achieved relative quantitative predictions, providing valuable insights for the regulation of conductivity in electronic biological devices. This research contributes to the advancement of knowledge in the field, offering a nuanced perspective on the interplay between crosslinkers, pore characteristics, and the conductivity of hydrogels.