(332g) Dielectric Permittivity and Relaxation Dynamics of Coacervates

Coacervates are found to respond to weak electric fields (of the order of 1 V/cm), which is significantly weaker than that necessitated by colloidal particles to exhibit a similar response. To solicit a reason for this sensitivity, we conducted dielectric relaxation spectroscopy (DRS) on coacervate films of Poly Diallyl dimethyl ammonium chloride (PDDA; MW = 8.5 kDa) and Adenosine Triphosphate (ATP). Through DRS, the relative dielectric permittivity of PDDA-ATP coacervates was significantly high, comparable to that of inorganic materials like BaTiO₃, which are deemed as potential supercapacitors. This result explains the high sensitivity of coacervates to weak electric fields and opens avenues for utilizing them in high-energy-density storage devices or wound-healing formulations. We also delve into the variation of dynamic relaxation of coacervates with temperature, water content, and cohesive energy density. Apart from understanding the relationship between relaxation times and these parameters, we also investigate how these parameters, in particular cohesive energy density, affect the glassy behavior and fragility of the coacervates.