Article
Polymer Science
Neel J. Shah, Sajjad Dadashi-Silab, Michael D. Galluzzo, Saheli Chakraborty, Whitney S. Loo, Krzysztof Matyjaszewski, Nitash P. Balsara
Summary: The study investigated the impact of salt addition on a diblock copolymer system with a negative Flory-Huggins interaction parameter, chi. It was found that ordered phases only appear under specific conditions, as predicted by ionic self-consistent field theory.
Article
Polymer Science
Chao Fang, Whitney S. Loo, Rui Wang
Summary: This study quantifies the salt activity coefficient and polymer chain statistics of PEO/LiTFSI mixture at experimentally relevant salt concentrations using molecular dynamics simulations. Near the critical salt concentration, a small plateau in the dependence of salt activity coefficient on salt concentration is observed and the dependence of polymer chain size on salt concentration exhibits a reversal from contraction to expansion, in agreement with experimental observations.
Article
Polymer Science
Gregory W. Peterson, Thomas H. Epps
Summary: The effect of seeding PEO solutions with zinc acetate and zinc chloride on solution properties and the ability to electrospin nanofibers was investigated. The addition of zinc salts had varying effects on solution viscosity and electrical conductivity, resulting in changes in fiber morphology. The presence of salts increased the electrical conductivity of the solution, allowing for electrospinning at lower polymer concentrations.
Article
Chemistry, Physical
Steven W. Rick
Summary: A thermal responsive block copolymer made up of ethylene oxide (EO) and propylene oxide (PO) blocks was simulated at different temperatures, showing aggregation behavior in dilute solution that is stabilized by hydrophobic contact of propylene oxide methyl groups. The study compared the aggregation tendency of different polymers in solution and highlighted the importance of hydrophobic interactions in the aggregation process.
JOURNAL OF PHYSICAL CHEMISTRY B
(2021)
Article
Environmental Sciences
Esmaeel Sharifi, Rezvan Jamaledin, Fatemeh Familsattarian, Fereshteh Nejaddehbashi, Mitra Bagheri, Mohammad Chehelgerdi, Ehsan Nazarzadeh Zare, Omid Akhavan
Summary: This research evaluated the potential of bioactive chitosan@poly (ethylene oxide)@CuFe2O4 (CS@PEO@CF) nanofibers in wound healing. The nanoparticles showed antibacterial and antioxidant properties and did not adversely affect fibroblast cell viability. The nanofibrous mats promoted cell migration and growth at the wound edge, leading to enhanced wound healing and regeneration of sebaceous glands and hair follicles within the skin.
ENVIRONMENTAL RESEARCH
(2023)
Article
Polymer Science
Chunhua Zhu, Ning Wei, Junhua Zhao
Summary: This study successfully describes the interactions between poly(vinyl alcohol) (PVA) melts and graphene oxide (GO), as well as their interfaces, using coarse-grained potentials. The computational efficiency is significantly improved and the method can be applied to other interfacial systems.
Article
Chemistry, Physical
Cindy Mutiara Septani, Meng-Fan Ku, Chun-Yu Chen, Jhih-Min Lin, Ya-Sen Sun
Summary: The micellization, aggregation, and gelation behavior of polystyrene-block-poly(ethylene oxide) block copolymer in solution were analyzed using small-angle X-ray scattering. It was found that the content and concentration of added hydrochloric acid affected the behavior of the block copolymer, such as the formation and aggregation of micelles and the occurrence of gelation.
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
(2022)
Article
Chemistry, Physical
Carlos A. Salinas-Soto, Yeojin Choe, Su-Mi Hur, Abelardo Ramirez-Hernandez
Summary: In this study, extensive simulations were performed using dissipative particle dynamics to investigate the effect of grafting density, backbone length, and sidechain length on the conformations of comb-like polymers. The simulation results reveal that the effective Kuhn length increases as grafting density and sidechain length increase, resulting in comb-like polymers adopting extended conformations.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Polymer Science
Congzhi Zhu, Aaron A. Burkey, Cameron P. Adams, Diego Uruchurtu Patino, Nathaniel A. Lynd
Summary: Orthoester-containing copolymers are degradable under mild acidic conditions, making them suitable for applications in drug delivery, photolithography, and disposable plastics with environmental remediation. These copolymers combine the degradation properties of polyorthoesters with the structural diversity of polyethers.
Article
Chemistry, Physical
Lakshmikumar Kunche, Upendra Natarajan
Summary: We propose the GB-OBC model for implicit-solvent MD simulations of synthetic macromolecules in water, which successfully reproduces chain dimensions and predicts the free energy of solvation of carboxylic acid vinyl polymers. We investigate the influence of stereochemistry and hydrophobicity as a function of chain length for PAA and PMA. The GB-OBC model parameters are parameterized for PAA and PMA. The results show that the atactic chain is more soluble in water and the PMA chain is more conformationally perturbed compared to the isotactic chain.
JOURNAL OF PHYSICAL CHEMISTRY B
(2023)
Article
Polymer Science
Xiangning Wen, Yunlan Su, Shaofan Li, Weilong Ju, Dujin Wang
Summary: The study demonstrated that PEG-g-SiO2 can significantly increase the crystallinity and crystallization temperature of PEO matrix, affecting the crystalline morphology and rate of PEO. The good dispersion of PEG-g-SiO2 in the PEO matrix contributes to enhancing the primary nucleation rate.
Article
Chemistry, Physical
Yogendra Kumar, Upendra Natarajan
Summary: The inter-macromolecular interaction between uncharged polymers in aqueous solutions is influenced by various factors including polymer concentration, solvent quality, molecular weight, solution pH, temperature, salt concentration, and type of salt. Atomistic molecular dynamics simulations were performed to study the behavior of poly(acrylic acid) and poly(ethylene oxide) in aqueous NaCl solution. The results showed that increasing salt concentration reduces the size of polymer chains due to the water becoming a poor solvent, leading to enhanced polymer compositing. At high salt concentration, a close interaction occurs between the carboxylic hydrogen and ether oxygen of the polymer. The solubility of the chains decreases and reaches a minimum energy conformation at a specific salt concentration. The simulation results were consistent with experimental data available in literature.
MOLECULAR SIMULATION
(2023)
Article
Polymer Science
Supanont Jamornsuriya, Visit Vao-soongnern
Summary: Monte Carlo simulation was used to investigate the structures and dynamics of ethylene-propylene copolymer melts with different compositions and sequences. The dynamics of the copolymer chains were found to be dependent on the ethylene fraction, with block-like sequences showing faster molecular mobility. The intermolecular packing and chain dimension were affected by the monomer sequences, especially at higher ethylene fractions.
JOURNAL OF POLYMER RESEARCH
(2022)
Article
Plant Sciences
Suhas Balasaheb Karle, Akankhya Guru, Padmanabh Dwivedi, Kundan Kumar
Summary: Salinity stress negatively affects plant growth and development, but plants can maintain homeostasis and enhance resilience through the involvement of gaseous molecules. Gasotransmitter plays a crucial role in salinity stress by regulating antioxidant molecules and improving plant adaptability to stress.
JOURNAL OF PLANT GROWTH REGULATION
(2021)
Article
Materials Science, Ceramics
Munirah Jamil, Iskandar Shahrim Mustafa, Naser Mahmoud Ahmed, Shahrul Bariyah Sahul Hamid, Thair Hussien Khazaalah, Efenji Godwin, Nabasu Seth Ezra, Hayder Naeem Salah
Summary: Novel magnetic resonance imaging (MRI) diagnostic nanofibres were synthesized by embedding Er2O3 nanoparticles (2% to 8%) in the PEO matrix using electrospinning. The resulting PEO/Er2O3 nanofibres were characterized and evaluated for their magnetic relaxivity in MRI contrast enhancement. The addition of Er2O3 nanoparticles led to changes in the conformational structure and crystalline properties of the nanofibres, demonstrating potential T2 and T1-T2 dual-mode diagnostic capabilities in MRI 1.5T.
CERAMICS INTERNATIONAL
(2023)
Article
Chemistry, Medicinal
Sichen Song, Chenguang Wang, Bo Zhang, Changquan Calvin Sun, Timothy P. Lodge, Ronald A. Siegel
Summary: This study reports a method of miscibility determination based on the overlap concentration, c*, which can be conveniently determined from the viscosity-composition diagram. The determined c* values strongly correlate with the physical stability of amorphous solid dispersions (ASDs) of two model drugs, celecoxib and loratadine, with four different grades of polyvinylpyrrolidone (PVP). This suggests the potential application of the c* concept in designing stable high drug loaded ASD formulations and provides a procedure for broader adoption of this methodology, which is easy to apply and widely applicable for thermally stable binary drug/polymer combinations.
JOURNAL OF PHARMACEUTICAL SCIENCES
(2023)
Review
Polymer Science
Saptasree Bose, Victoria Padilla, Alexandra Salinas, Fariha Ahmad, Timothy P. Lodge, Christopher J. Ellison, Karen Lozano
Summary: Nanofibers have unique properties that have attracted significant interest, such as high specific surface area, high aspect ratio, and spatial interconnectivity. Design strategies, including core-sheath, concentric layers, and particle distribution, are being used to prescribe the internal structure of nanofibers. This review provides a comprehensive overview of the design strategies being used to produce the next generation of nanofiber systems, discussing processing methods and their effects on the nano- and microstructure, as well as physico-chemical effects on fiber morphology.
Article
Biochemistry & Molecular Biology
Yimin Mao, Jialiang Shi, Liming Cai, Wonseok Hwang, Yong-Cheng Shi
Summary: In this study, different starches with varying moisture levels were investigated using small-angle neutron and X-ray scattering. The microstructure parameters such as inter-lamellar distance and crystalline lamellar thickness were found to be closely related to starch properties. The study emphasized the importance of comprehensive analysis of different parameters to understand the microstructure of starch.
Article
Nanoscience & Nanotechnology
Timothy P. Lodge, Frank S. Bates, Michael B. Sims, Joshua W. Goetze, Gabriela Diaz Gorbea, Zachary M. Gdowski
Summary: We propose an approach to photocrosslink bicontinuous microemulsions derived from ternary blends, enabling detailed structural characterization. This strategy utilizes a photodimerization reaction to covalently crosslink blends, preserving the intricate network structure. The resulting crosslinked microemulsions exhibit rubbery behavior at elevated temperatures and can be imaged by microscopy techniques. The versatile nature of this strategy is demonstrated by achieving a heterogeneous solid electrolyte with high conductivity.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Energy & Fuels
Chelsea W. Neil, Rex P. Hjelm, Marilyn E. Hawley, Erik B. Watkins, Yimin Mao, Rajesh Pawar, Hongwu Xu
Summary: This study used small angle neutron scattering (SANS) and ultra-small-angle neutron scattering (USANS) to investigate the retention and location of oil in shale samples with different mineralogical compositions. The results showed that decane was significantly retained in 1.5-10 nm radius pores of both samples, indicating retention within kerogen nanopores. The light sample, despite having lower porosity, had more accessible pores and a higher percentage of removable decane compared to the dark sample. These findings can help to model oil recovery from heterogeneous shale formations and improve enhanced oil recovery strategies.
Article
Chemistry, Multidisciplinary
Nicholas J. Van Zee, Amanda S. Peroutka, Marc A. Hillmyer, Timothy P. Lodge
Summary: Poloxamers, also known as Pluronics, have been found to alleviate cellular membrane damage, but the underlying protection mechanism is still unclear. This study investigated the impact of poloxamer molar mass, hydrophobicity, and concentration on the mechanical properties of lipid vesicles, revealing that poloxamers tend to decrease the stretching modulus. The study provides important insights into how poloxamers interact with lipid membranes and protect cells from various stresses.
Article
Polymer Science
Supriya Gupta, Lucy Liberman, Timothy P. Lodge
Summary: The fragmentation kinetics of 1,2-polybutadiene-bpoly(ethylene oxide) block copolymer micelles was investigated, with a focus on the role of driving force for micellar fragmentation. Large micelles were formed in an ionic liquid by the direct dissolution method, and a broad range of micelle sizes was obtained by altering the solvent quality. The rate of fragmentation was found to be significantly influenced by the driving force, leading to a systematic acceleration of the kinetics.
Article
Polymer Science
Supriya Gupta, Timothy P. Lodge
Summary: This study investigates the fragmentation mechanism of block copolymer micelles in ionic liquids. It is found that the driving force for micelle fragmentation can be enhanced by controlling the amount of low interfacial tension solvent, leading to faster fragmentation.
Article
Polymer Science
Bo Zhang, Shuquan Cui, Timothy P. Lodge, Frank S. Bates
Summary: In this study, the structure and phase behavior of ternary mixtures containing AB bottlebrush diblock copolymer and A and B linear homopolymers were systematically investigated using small-angle X-ray scattering and cloud point measurements. The overall phase behavior of these mixtures closely resembles the linear counterparts, but with a significantly weaker increase in lamellar and microemulsion domain spacing as the homopolymer content increases. This behavior is attributed to an unconventional spatial distribution of the homopolymer within the bottlebrush architecture of the diblock copolymer. These ternary mixtures offer a promising platform for designing cocontinuous materials with an expanded parameter space using bottlebrush polymers.
Article
Chemistry, Multidisciplinary
Joseph F. Hassler, Megan Lawson, Erika Cerna Arroyo, Frank S. Bates, Benjamin J. Hackel, Timothy P. Lodge
Summary: Poloxamers, composed of PEO and PPO blocks, interact with phospholipid bilayers and alter their mechanical and surface properties. This study used NMR spectroscopy to measure the binding affinity of Poloxamers to liposomes at different temperatures and found a significant increase in binding affinity at higher temperatures. Moreover, the polymer chains can penetrate the bilayer and access the interior of liposomes at elevated temperatures, which is not possible at lower temperatures. This research reveals the molecular mechanism of Poloxamer-lipid bilayer interactions and has important implications for modulating the properties of liposomes and cell membranes.
Article
Polymer Science
Timothy P. Lodge, En Wang, Jiahao Zhu, Frank S. Bates
Summary: The self-assembly behavior of four polystyrene and poly(ethylene-alt-propylene) block copolymers in a selective solvent was studied. Spherical micelles were formed by all four polymers, with the symmetric triblock copolymer having the smallest micelle size. However, the asymmetric triblock copolymers did not form any specific packing arrangement. This result suggests that the two-layer corona of the asymmetric triblock copolymers may play a role in their self-assembly behavior. At higher concentrations, all four polymers adopted hexagonal packings before transitioning to lamellar structures.
Article
Chemistry, Physical
Caini Zheng, Bo Zhang, Frank S. Bates, Timothy P. Lodge
Summary: The self-assembly behavior of ternary blends of polystyrene (PS) and poly[oligo(ethylene glycol) methyl ether methacrylate] (POEGMA(n)) with different lengths of oligo(ethylene glycol) side chains n was investigated in this study. Small-angle X-ray scattering was used to examine the phase behavior at different compositions and temperatures. The results showed that the side chain length impacted the order-to-disorder transition temperature and longer side chains resulted in poorer miscibility of homopolymers in the corresponding block, leading to a more dry-brush like swelling behavior.
Article
Polymer Science
Timothy P. Lodge, Claire L. Seitzinger
Summary: By incorporating a photoactive moiety into a block polymer, the phase behavior of the polymer solution can be controlled with light. The positioning of the pendant azobenzene groups along the polymer backbone significantly affects the order-disorder transition of the polymer in the ionic liquid. Adjusting the location of the azobenzene units within the thermo-and photoresponsive polymer solution changes the overall behavior of the solutions and the ability to control that behavior with light and temperature.