Study of denaturation and composition‐dependent poly(ethylene oxide)–soy protein interactions: Structures and dielectric polarization

Abstract

The significance of aggregated protein structures in tuning structures and dielectric polarization of poly(ethylene oxide) (PEO)/soy protein isolate (SPI) films was studied. The aggregated protein structures, subjected to denaturation processes, are expected to alter polymer–protein interactions, leading to diverse material structures, and properties. However, this is still insufficiently understood. In this study, SPI was modified via different denaturation processes including heat, sonication, and pH‐control. According to structural analysis with scanning electron microscope, fluorescence imaging, X‐ray diffraction, and Fourier transformed infrared spectroscopy, both denaturation conditions and SPI content affected PEO–SPI interactions, producing distinctive microstructures of PEO and SPI phases, which subsequently caused different dielectric properties in ferroelectric analysis. Particularly, sonication treated‐SPI distinguished itself by generating a unique parabolic‐like composition dependence of dielectric polarization, in contrast to other modified SPIs. Polymer/protein blends have shown great potential in biomedical and electronic applications, which will be further benefited by the findings in this study. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46561.

Numerical study on mechanisms of soy protein as a functional modifier for polymer materials

“…By blending with proteins, the bio-performances of petroleum-based polymers, such as biocompatibility, degradation rate and solubility were improved [18,19]. In our preliminary studies, we found that the diverse polymer-protein interactions played important roles in tuning microstructures and properties of the resulting composites [20][21][22][23][24]. 2S fraction of protein was studied as a non-covalent surfactant for polymer nanocomposites [20].…”

“…With the variation of protein modifier concentration, the properties of the poly(vinylidene fluoride) (PVDF), including dielectric constant and ferroelectric hysteresis, were remarkably altered [21]. Moreover, we found that by controlling the denaturation conditions of protein, protein modifiers possessed different structures and properties, and were able to vary the microstructures and dielectric properties of hydrophilic poly(ethylene oxide) (PEO) [23] and hydrophobic PVDF polymers [22].…”

“…Although various efforts [20][21][22][23][24] have been conducted to explain the underlying mechanisms of how the structures and properties of polymers are affected by protein molecules, it is still very challenging to investigate them via experimental approaches. This is because, it is difficult to observe the transient conformational changes of protein at molecule/ atomistic-level directly by using experimental methods, as well as to acquire detailed information regarding the interactions between protein molecules and polymer chains.…”