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1. Techniques to characterize dynamics in biomaterials microenvironments: XPCS and microrheology of alginate/PEO–PPO–PEO hydrogels

   https://doi.org/10.1039/d0sm01628d  

   Quah, Suan P.; Zhang, Yugang; Fluerasu, Andrei; Yu, Xiaoxi; Zheng, Bingqian; Yin, Xuechen; Liu, Weiping; Bhatia, Surita R. (February 2021, Soft Matter)

   null (Ed.)

   Many recent studies have highlighted the timescale for stress relaxation of biomaterials on the microscale as an important factor in regulating a number of cell-material interactions, including cell spreading, proliferation, and differentiation. Relevant timescales on the order of 0.1–100 s have been suggested by several studies. While such timescales are accessible through conventional mechanical rheology, several biomaterials have heterogeneous structures, and stress relaxation mechanisms of the bulk material may not correspond to that experienced in the cellular microenvironment. Here we employ X-ray photon correlation spectroscopy (XPCS) to explore the temperature-dependent dynamics, relaxation time, and microrheology of multicomponent hydrogels comprising of commercial poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (PEO–PPO–PEO) triblock copolymer F127 and alginate. Previous studies on this system have shown thermoreversible behavior in the bulk oscillatory shear rheology. At physiological temperatures, bulk rheology of these samples shows behavior characteristic of a soft solid, with G ′ > G ′′ and no crossover between G ′ and G ′′ over the measurable frequency range, indicating a relaxation time >125 s. By contrast, XPCS-based microrheology shows viscoelastic behavior at low frequencies, and XPCS-derived correlation functions show relaxation times ranging from 10–45 s on smaller length scales. Thus, we are able to use XPCS to effectively probe the viscoelasticity and relaxation behavior within the material microenvironments. 

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2. Temperature‐Dependent Structure of Alginate/ PEO – PPO – PEO /Nanoclay Composite Hydrogels

   https://doi.org/10.1002/pat.70385  

   Zhu, Hengwei; Hom, Wendy L; Zheng, Bingqian; Shen, Jiachun; Bhatia, Surita R (October 2025, Polymers for Advanced Technologies)

   ABSTRACT Formation of alginate‐based interpenetrating networks and addition of nanoparticles into these gels are widely used strategies to enhance the mechanical properties of alginate gels used for delivery and biomedical applications. Our previous work demonstrated that alginate‐clay nanocomposite hydrogels containing poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (PEO–PPO–PEO) copolymers exhibited significant enhancement of elasticity and temperature‐dependent rheology. However, the behavior of PEO–PPO–PEO copolymers within an alginate network remains unclear. In this study, we use small‐angle neutron scattering (SANS) to investigate the interactions between the alginate network and PEO–PPO–PEO triblock chains. Our fitting results revealed that the triblock chains can form micelles integrated into the alginate gel “egg box” structure at higher temperatures. The presence of the alginate network influences the formation of PEO–PPO–PEO micelles in our gels, leading to elongated ellipsoidal micelles rather than spherical micelles. Interestingly, as the temperature increased, these micelles did not expand in all three dimensions, as observed for pure PEO–PPO–PEO solutions. Rather, the total size increased only in one direction while remaining the same in the other two directions, suggesting that the alginate networks restrict the growth of micelles. Furthermore, we did not observe the distinct higher‐order peaks that are typical of cubic PEO–PPO–PEO hydrogels; rather, relatively weak secondary peaks were observed. These results demonstrate that the presence of the alginate network significantly influences micelle formation and assembly in composite hydrogel systems. 

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3. Electrostatic focusing of electrospun Polymer(PEO) nanofibers

   https://doi.org/10.1016/j.elstat.2018.05.001  

   Kyselica, Rudolf; Enikov, Eniko T.; Polyvas, Peter; Anton, Rein (August 2018, Journal of Electrostatics)
4. Composite PEDOT:PSS‐PEO Layers for Improving Lithium Batteries**

   https://doi.org/10.1002/celc.202400458  

   Ritter, Timothy_G; Il_Kim, Yong; Bezerra_De_Souza, Breno; Wang, Xinnian; Pan, Yayue; Yurkiv, Vitaliy; Yarin, Alexander_L; Shahbazian‐Yassar, Reza (October 2024, ChemElectroChem)

   Abstract This work investigates the application of poly(3,4‐ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS) with polyethylene oxide (PEO) in lithium batteries (LIBs). This composite film comprising PEDOT:PSS and PEO was 3D printed onto a carbon nanofiber (CNF) substrate to serve as a layer between the polypropylene (PP) separator and the lithium anode in LIBs. The resulting CNF‐PEDOT:PSS‐PEO film exhibited superior mechanical and thermal properties compared to conventional PP separators. Mechanical tests revealed a high Young's modulus and puncture strength for the composite film. Thermal stability tests indicated that the CNF‐PEDOT:PSS‐PEO film remained stable at higher temperatures compared to the commercial PP separator, and combustion tests confirmed its superior fire‐resistance properties. In terms of conductivity, the composite film maintained comparable ionic conductivity to the commercial PP separator. Electrochemical tests demonstrated that LIBs incorporating the CNF‐PEDOT:PSS‐PEO film exhibited slight improvement in cycling performance, with a 7.9 % increase in long‐term cycling capacity compared to LIBs using only the commercial PP separator. These findings indicate that the developed CNF‐PEDOT:PSS‐PEO composite film holds promise to improve safety, while maintaining the electrochemical performance of LIBs by reducing dendrite formation and enhancing thermal stability. 

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5. Effect of Ionic Liquid Components on the Coil Dimensions of PEO

   https://doi.org/10.1021/acs.macromol.9b00354  

   Kharel, Aakriti; Lodge, Timothy P. (April 2019, Macromolecules)