Article
Polymer Science
Peyton Carden, Sirui Ge, Sheng Zhao, Bingrui Li, Subarna Samanta, Alexei P. Sokolov
Summary: Polymers with dynamic bonds have unique properties such as self-healing and recycling, but understanding their dynamics and viscoelastic properties, especially in the case of phase-separated dynamic bonds, is limited. This study analyzes model polymer systems with phase-separating dynamic bonds and reveals that the bond rearrangement process is controlled by the pullout of a sticker from a cluster. The total concentration of stickers plays a critical role in controlling the dynamics of the polymer, regardless of sticker placement and chain length.
Article
Polymer Science
Masayuki Hibino, Shin-ichi Takata, Kosuke Hiroi, Hiroyuki Aoki, Takaya Terashima
Summary: Amphiphilic random copolymers with PEG and alkyl groups form size-controlled micelles in water. The exchange kinetics and mechanism of the copolymer chains between micelles were investigated using TR-SANS. The exchange involved two mechanisms: a dominant unimer release and insertion pathway under diluted conditions, and an increasing contribution of micelle collision pathway with higher polymer concentration and temperature. The activation energy for the exchange process was dependent on the hydrophobic alkyl groups.
Article
Biochemistry & Molecular Biology
Jing Yu, Kai Xu, Xiaojing Chen, Xiaodan Zhao, Yuxuan Yang, Dake Chu, Yongliang Xu, Qiang Zhang, Yanfeng Zhang, Yilong Cheng
Summary: In this study, an advanced hydrogel was prepared through one-pot free-radical copolymerization, demonstrating excellent mechanical properties and biocompatibility, with vast potential in biomedical and flexible electronic applications.
Article
Polymer Science
Xuan Feng, Nan Yan, Jing Jin, Wei Jiang
Summary: The disassembly process of amphiphilic AB block copolymers in selective solvents was investigated using molecular dynamic simulation. The disassembly is controlled by thermodynamic processes that depend on the instability of the system. Bx can be converted to Ax in A2BxB18-x diblock copolymers by external stimuli, and the instability induced by Bx conversion is a function of x. Increasing x leads to the disassembly of the initial vesicles into various structures. In addition, the Bx conversion rate and the amount of converted polymer chains also affect the disassembly process.
Article
Chemistry, Multidisciplinary
Binny A. Rudani, Jayant Sarolia, Ragini Rai, Vinod K. Aswal, Pratap Bahadur, Sanjay Tiwari
Summary: We conducted a comprehensive study on the interaction of tetronics (T1304 and T1307) with important physiological salts (NaH2PO4, KH2PO4, Na2CO3, NaCl, and KI). We investigated the thermodynamic and microstructural aspects of these interactions, considering factors such as solution temperature, pH, and salt concentration. Our findings reveal that T1304 molecules form aggregated core-shell structures at ambient temperature, while T1307 exhibits the dominance of unimers and large clusters. The presence of salts promotes micellization, with NaCl < KH2PO4 < NaH2PO4 MUCH LESS THAN Na2CO3 in terms of their effectiveness. The interaction is characterized by endothermic aggregation and prevailing hydrophobic interactions. KI induces demicellization by facilitating the buildup of water structures around the copolymer chains.
Article
Chemistry, Multidisciplinary
Taylor Larison, Morgan Stefik
Summary: Polymer micelles have significant applications in medicine and nanomaterials, with their performance depending on size and chemical functionalization. PMCC allows for size-controlled functionalization of micelles, achieved through synthetic planning and polymer solubility databases. This method enables constant average micelle core dimensions and maintenance of micelle core size during modifications via pH changes.
Article
Polymer Science
Inge Bos, Marga Timmerman, Joris Sprakel
Summary: Complex coacervate core micelles (C3Ms) are nanoscopic structures used to encapsulate charged molecules, with molecular exchange dynamics influenced by factors such as salt concentration. The exchange of equilibrated C3Ms is mainly driven by expulsion and insertion processes, with ionic bond breaking as the rate-limiting step. These insights can help improve the encapsulation efficiency of C3Ms.
Article
Polymer Science
Douglas J. Grzetic, Anthony J. Cooper, Kris T. Delaney, Glenn H. Fredrickson
Summary: Block copolymers have the potential to form isoporous integral-asymmetric membranes through the combined processes of self-assembly and non-solvent-induced phase separation (SNIPS). However, the dependence of surface layer and substructure morphologies on the processing variables associated with SNIPS is not well understood. This study uses dynamical self-consistent field theory to simulate the microstructure evolution of block copolymer films during SNIPS and reveals the importance of solvent and non-solvent selectivity in achieving the desired porous substructure.
Article
Chemistry, Physical
Taylor Larison, Sai Venkatesh Pingali, Morgan Stefik
Summary: Chain exchange in amphiphilic block polymer micelles can be measured using time-resolved small-angle neutron scattering (TR-SANS). However, analyzing chain mixing during micelle transformations on short time scales is challenging due to low data statistics. A new approach called shifting references relaxation (SRR(t)) is proposed, which enables the calculation of mixed states regardless of short acquisition times by acquiring reference patterns at each time point. SRR(t) is compatible with arbitrary levels of complexity and can accurately assess the mixed state, supporting future model analysis.
Article
Polymer Science
Meng Liu, Lu Yin, Yue Zhao
Summary: This study investigates the effects of spacer and mesogen on the stretching-induced orientation of mesogens in liquid crystal elastomer (LCE) actuators. The results show that varying the length of spacer or changing the mesogen significantly affects the orientation direction, degree, and stability of the LCEs. The characteristic orientation behaviors of the LCEs are retained in their respective actuators, determining their reversible actuation upon heating and cooling.
Article
Food Science & Technology
Jinlong Li, Shan Jiang, Xin Jia, Lijun Yin
Summary: The 'interfacial quality' is crucial for the catalytic activity of lipases, and interfacial engineering can effectively modulate lipase catalysis. In this research, triblock copolymers PEO-PPO-PEO were used to create oil-in-water (O/W) emulsion systems. The study found that PEO-PPO-PEO molecules had different effects on spatial barriers, emulsion particle size, and interfacial adsorption properties of lipases. CALB had higher adsorption ratio due to its smaller molecular weight, allowing it to pass through the adsorption layer more easily. However, its catalytic efficiency at emulsion interfaces was lower than that of CRL, which can be attributed to the lack of a typical 'lid' structure. The amount of lipase at interfaces and the specific surface area of the emulsion impacted the catalytic activities of CRL. Na+ ions were found to inhibit the catalytic activity of CRL to some extent.
LWT-FOOD SCIENCE AND TECHNOLOGY
(2022)
Article
Polymer Science
Chao Lv, Jia Gao, Kun An, Jingjing Nie, Junting Xu, Binyang Du
Summary: A series of pH-sensitive and thermosensitive amphiphilic pentablock copolymers were self-assembled into micelles with different morphologies and structures, exhibiting varying thermosensitive behavior and nanostructures under different pH conditions.
Article
Polymer Science
Joanna M. White, Adelyn A. Crabtree, Frank S. Bates, Michelle A. Calabrese
Summary: Poloxamers, ABA triblock polymers, have been extensively studied for biomedical applications. Reverse P407, a polymer with an inverted architecture, exhibits higher gelation and micellization temperatures compared to P407, and displays interesting rheological behavior. Blending P407 and RP407 alters the micelle size and packing, which could have implications for drug delivery and protein stabilization applications.
Article
Polymer Science
Taylor Larison, Eric Williams, Coby S. Collins, Sai Venkatesh Pingali, Morgan Stefik
Summary: Ultrasonic cavitation can temporarily activate chain exchange in block polymer micelles for deeper mixing. In situ SANS measurements revealed two distinct mixing rates during cavitation, with a fast initial rate followed by a slower steady rate. Both gas-bubble and vapor-bubble cavitation showed exchange rates directly proportional to the polymer concentration, indicating no steric hindrances.
Article
Chemistry, Multidisciplinary
Mingxin Zheng, Qiquan Ye, Xi Chen, Min Zeng, Guangjie Song, Jun Zhang, Jinying Yuan
Summary: In this study, an effective method for preparing high solid content azobenzene-containing triblock copolymer toroidal assemblies is presented using liquid crystallization-assisted seeded dispersion polymerization. Toroids are formed in situ during the polymerization by introducing smectic liquid crystalline ordering into the core-forming block, and the morphological transformation from toroids to barrels is observed under ultraviolet irradiation due to the photo-isomerization of the azobenzene mesogens.
CHEMICAL COMMUNICATIONS
(2022)
Article
Polymer Science
Joseph F. Hassler, Nicholas J. Van Zee, Adelyn A. Crabtree, Frank S. Bates, Benjamin J. Hackel, Timothy P. Lodge
Summary: This work presents a synthetic strategy for making grafted block polymers with poly(propylene oxide) and poly(ethylene oxide) side chains, known as bottlebrush analogues of poloxamers. The bottlebrush architecture results in higher critical micelle concentration compared to linear analogues, allowing the polymers to exist as unimers at higher molecular weights and concentrations in solution.
Article
Polymer Science
Lucy Liberman, McKenzie L. Coughlin, Steven Weigand, Jerrick Edmund, Frank S. Bates, Timothy P. Lodge
Summary: Different molecular architectures of diblock polymers were investigated for their effects on phase behavior, specifically the self-assembly into network morphologies. Various linear-bottlebrush diblock polymers were synthesized and their phase behavior was studied using X-ray scattering techniques.
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
Polymer Science
Claire L. Seitzinger, Timothy P. Lodge
Summary: By incorporating a photoactive moiety into a block polymer, the phase behavior of the polymer can be controlled with light. The positioning of pendant azobenzene groups along the polymer backbone significantly affects the phase transition temperature and the ability to control the behavior with light and temperature. By adjusting the location of the azobenzene units within the polymer solution, the overall behavior of the solution can be changed.
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
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
Materials Science, Multidisciplinary
Bo Zhang, Caini Zheng, Frank S. Bates, Timothy P. Lodge
Summary: Charged block copolymers have potential as next generation battery electrolytes due to their ability to self-assemble into various nanostructures with high ionic conductivity and mechanical strength. This study investigates the impact of ions on the self-assembly of charged block copolymers by employing a nonpolar matrix to enhance electrostatic interactions. The phase behavior was analyzed using small-angle X-ray scattering (SAXS), revealing an asymmetric shape of the phase boundary and comparable composition windows of ordered phases to neutral diblock copolymers. These findings provide insight into the design of nanostructured polymer electrolytes and the influence of ions on charged block copolymer self-assembly.
ACS APPLIED POLYMER MATERIALS
(2023)
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.