Open Access Publications - Materials Science and Engineering

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Open access publications by faculty, postdocs, and graduate students in the Department of Materials Science and Engineering

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Elastic Coefficients of Polyether Ether Ketone from First-Principles Calculations
(Materials Research, 2025-11-07) Di Benedetto, Ricardo Mello; Janotti, Anderson; Ancelotti Junior, Antonio Carlos; Botelho, Edson Cocchieri
First-principles calculations based on the density functional theory (DFT) represent a sophisticated technique to investigate the mechanical strength of materials in general, although underexplored in polymeric structures such as high-performance thermoplastic polymers. In this study, DFT calculations were systematically conducted to evaluate the effects of strain on the structure of polyether ether ketone, determining the maximum elasticity modulus in a perfect alignment condition of the polymer chain. The atom positions and arrangement of the polymer chains were set based on total energy and force minimizations. The four lowest energy structures were stretched up to 10 Å per monomer, and the results have shown a mean elasticity modulus of 5.93±0.74 GPa, which we attribute to the upper limit for aligned and stretched polymeric chains.
Mechanical friction data associated with "Alternatives to Friction Coefficient: Role of Frictional Instabilities on Fine Touch Perception" by Derkaloustian et al.
(2025-11-17) Derkaloustian, Maryanne; Bhattacharyya, Pushpita; Ngo, Truc; Cashaback, Joshua G. A.; Medina, Jared; Dhong, Charles B.
Building an affordable self-driving lab: Practical machine learning experiments for physics education using Internet-of-Things
(APL Machine Learning, 2025-10-29) Liu, Yang; Lei, Qianjie; He, Xiaolong; Xue, Yizhe; Yang, Haitao; Zhang, Xian; Yang, Li; Zhou,Yichun; Hu, Ruiqi; Xie, Yong
Machine learning (ML) is transforming modern physics research, but practical, hands-on experience with ML techniques remains limited due to cost and complexity barriers. To address this gap, we introduce an affordable, autonomous, Internet-of-Things (IoT)-enabled experimental platform designed specifically for applied physics education. Utilizing an Arduino microcontroller, a customizable multi-wavelength light emitting diode array, and photosensors, our setup generates diverse, real-time optical datasets ideal for training and evaluating foundational ML algorithms, including traversal methods, Bayesian inference, and deep learning. The platform facilitates a closed-loop, self-driving experimental workflow, encompassing automated data collection, preprocessing, model training, and validation. Through systematic performance comparisons, we demonstrate the superior ability of deep learning to capture complex nonlinear relationships compared to traversal and Bayesian methods. At ∼$60, this open-source IoT platform provides an accessible, practical pathway for students to master advanced ML concepts, promoting deeper conceptual insights and essential technical skills required for the next generation of physicists and engineers.
Magnon-induced electric polarization and magnon Nernst effects
(Proceedings of the National Academy of Sciences (PNAS), 2025-10-23) To, Duy Quang; Garcia-Gaitan, Federico; Ren , Yafei; M. O. Zide, Joshua; Jungfleisch, M. Benjamin; Xiao, John Q.; Nikolić, Branislav K.; Bryant, Garnett W.; Doty, Matthew F.
Magnons offer a promising path toward energy-efficient information transmission and the development of next-generation classical and quantum computing technologies. However, efficiently exciting, manipulating, and detecting magnons remains a critical need. We show that magnons, despite their charge-neutrality, can induce electric polarization through their spin and orbital moments. This effect is governed by system symmetry, magnon band hybridization, and interactions with other quasiparticles. We calculate the electric polarization induced by magnons in two-dimensional collinear honeycomb and noncollinear antiferromagnets (AFMs), showing that the presence of the Dzyaloshinskii-Moriya interaction yields a finite net electric polarization. In NiPSe3, a collinear honeycomb AFM with Zigzag order, the induced net electric polarization is about three orders of magnitude greater than in MnPS3, a collinear honeycomb AFM with Néel phase. In the noncollinear AFM KFe3(OH)6(SO4)2, the net electric polarization can be tuned via magnon hybridization, which can be controlled by external magnetic fields. These findings reveal that electric fields could be used to both detect and manipulate magnons under certain conditions by leveraging their spin and orbital angular moment. They also suggest that the discovery or engineering of materials with substantial magnon orbital moments could enhance practical uses of magnons for future computing and information transmission applications.
High-quality polycrystalline vanadium dioxide thin films deposited via pulsed laser deposition with high uniformity and consistency
(Journal of Materials Science: Materials in Electronics, 2025-10-25) Huang, Zhixiang; Laskowski,Kyle; Sitaram, Sai Rahul; Herrmann, Eric; Nobi, S M Jahadun; Ma, Ke; Wang, Xi
Vanadium dioxide (VO2) is a phase transition material that experiences significant shifts in electrical, optical, and mechanical properties near its transition temperature. Among various methods for depositing VO2 thin films, pulsed laser deposition (PLD) provides precise stoichiometric control, good versatility, and high consistency. In this work, we introduce an optimized PLD-based method for depositing high-quality polycrystalline VO2 thin films. Experimental results demonstrate a resistance change of over four orders of magnitude during the phase transition, accompanied by high uniformity, with a thickness variation of less than 2% across a 100 mm wafer, and reliable reproducibility over time.
Influence of boron-containing dopants on the structure and electrochemical properties of poly(3,4-ethylene dioxythiophene) (PEDOT)
(Journal of Materials Science, 2025-09-23) Cocuk, Nurdan; Wu,Yuhang; Lee, Junghyun; Baugh, Quintin; Martin, David C.
The choice of doping agents used during electrochemical polymerization is a crucial factor affecting the ultimate performance of poly(3,4-ethylenedioxythiophene) (PEDOT) thin films. Boron-containing dopants are a versatile group of materials that make it possible to conveniently tune PEDOT film structure and properties. Here, we investigated how several boron-containing dopants affect the structure and properties of electrodeposited PEDOT. The dopants examined were sodium tetrafluoroborate (NaBF4), sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaTFPB), and sodium tetraborate (Na2B4O7, Borax). We compared these results to a commonly used non-boron-containing dopant for PEDOT, lithium perchlorate (LiClO4). After electrodeposition, overall rough PEDOT film surfaces with varied morphological features, depending upon the utilized dopants were generated based on SEM. The low-frequency impedances of all PEDOT-coated electrodes were at least one order of magnitude lower than those of bare electrodes. The lowest impedances were observed for PEDOT/ClO4 and PEDOT/BF4, correlated with their doping levels by reaching the maximum threshold of 33%. These two also had similar and higher areal-specific capacitances with the values of 9.4 and 10.3 mF/cm2 than those of PEDOT/TFPB (3.3 mF/cm2) and PEDOT/B4O7 (0.2 mF/cm2) on smooth gold surfaces. Although their areal-specific capacitances were similar, the volumetric-specific capacitance of PEDOT/BF4 was 284 F/cm3 and almost doubled that of PEDOT/ClO4. For screen-printed electrodes, the areal-specific capacitance of PEDOT/TFPB was almost similar to the other two types, with the values of approximately 6.0 mF/cm2. We also demonstrated that PEDOT/TFPB is a particularly promising material with comparable properties and better cyclic stability.
Enhanced thermal response of 3D-printed bilayer hydrogels via nanoclay incorporation
(Molecular Systems Design & Engineering, 2025-06-11) Klincewicz, Francis; Kalidindi, Subhash; Liu, Siyuan; Sangroula, Kritee; Korley, LaShanda T. J.
Selective adsorption of hazardous micropollutants from water remains a critical challenge in sustainable materials design. Herein, we demonstrate a combined computational–experimental approach to rationally engineer molecularly imprinted polymers for targeted porosity, using 2,4,6-trinitrotoluene as a model template. By simulating pre-polymerisation mixtures of monomers, crosslinkers, and solvent using molecular dynamics, we capture key template–monomer interactions and predict the resulting porosity of the final polymer network. Surface area and free volume predictions from simulations show excellent agreement with experimental nitrogen sorption data across varying solvent compositions. Our findings highlight a fundamental trade-off between imprinting efficiency (favoured in acetonitrile-rich environments) and porous structure (promoted by dimethyl sulfoxide). We validate that pre-polymerisation simulations alone can accurately guide formulations toward high-performance materials, opening new pathways for computationally-driven design of porous polymeric adsorbents.
Zero-standby power hydrogen sensing using event-driven micromechanical switches
(Responsive Materials, 2025-08-09) Nobi, S M Jahadun; Herrmann, Eric; Huang, Zhixiang; Sitaram, Sai Rahul; Laskowski, Kyle; Wang, Xi
Zero-standby power sensors are crucial for enhancing the safety and widespreadadoption of hydrogen (H2) technologies in chemical processes and sustainable en-ergy applications, given the flammability of H2 at low concentrations. Here, we reportan event-driven hydrogen sensing system utilizing palladium (Pd)-based micro-mechanical cantilever switches. The detection mechanism relies on strain generationin the Pd layer, which undergoes reversible volume expansion upon hydrogenadsorption. Our experimental and simulation results demonstrate that the bistablemicromechanical switch-based sensor generates a wake-up signal with activationtime depending on hydrogen concentration in the target environment while alwaysremaining active for events without any standby power consumption under normalconditions. The H2 adsorption-induced subsequent switching of the multi-cantilever-based switch configuration on the sensor resulted in the quasi-quantification ofhydrogen concentrations. The reported zero-standby power sensor's operationallifetime is limited by the frequency of detection events and exposure to concentra-tions exceeding hydrogen's flammability limit. This work advances the developmentof high-density, maintenance-free sensor networks for large-scale deployment withInternet of Things devices, enabling unattended continuous monitoring of hydrogengeneration, transportation, distribution, and end-user applications.
Machine-learning-enabled on-the-fly analysis of RHEED patterns during thin film deposition by molecular beam epitaxy
(Journal of Vacuum Science & Technology A, 2025-05-01) Kaspar, Tiffany C.; Akers, Sarah; Sprueill, Henry W.; Ter-Petrosyan, Arman H.; Bilbrey, Jenna A.; Hopkins, Derek; Harilal, Ajay; Christudasjustus, Jijo; Gemperline, Patrick; Comes, Ryan B.
Thin film deposition is a fundamental technology for the discovery, optimization, and manufacturing of functional materials. Deposition by molecular beam epitaxy (MBE) typically employs reflection high-energy electron diffraction (RHEED) as a real-time in situ probe of the growing film. However, the state-of-the-art for RHEED analysis during deposition requires human observation. Here, we present an approach using machine learning (ML) methods to monitor, analyze, and interpret RHEED images on-the-fly during thin film deposition. In the analysis workflow, RHEED pattern images are collected at one frame per second and featurized using a pretrained deep convolutional neural network. The feature vectors are then statistically analyzed to identify changepoints; these changepoints can be related to changes in the deposition mode from initial film nucleation to a transition regime, smooth film deposition, and in some cases, an additional transition to a rough, islanded deposition regime. The feature vectors are additionally analyzed via graph analysis and community classification. The graph is quantified as a stabilization plot, and we show that inflection points in the stabilization plot correspond to changes in the growth regime. The full RHEED analysis workflow is termed RHAAPsody and includes data transfer and output to a visual dashboard. We demonstrate the functionality of RHAAPsody by analyzing the precaptured RHEED images from epitaxial depositions of anatase TiO2 on SrTiO3(001) and show that the analysis workflow can be executed in less than 1 s. Our approach shows promise as one component of ML-enabled real-time feedback control of the MBE deposition process.
Life Cycle Assessment of Thermoelectrics: Ecological Viability in Intermittent Waste Heat Scenarios
(ACS Omega, 2025-04-01) Iyer, Rakesh Krishnamoorthy; Sabet, Morteza; Pilla, Srikanth
This study evaluates the ecological impacts of thermoelectrics (TEs) in stationary applications that periodically generate waste heat using life cycle assessment (LCA) methodology, a first of its kind. Six TE modules are analyzed for a periodic heat-emitting application: a natural gas-based power plant that meets only peak electricity demand. The analysis uses detailed inventories from an earlier study regarding the production and end-of-life stages of the TEs. The results show that while TEs are effective in conserving fossil fuels and lowering greenhouse gas emissions, they do not exhibit significant positive effects on other environmental impacts. These findings persist even when accounting for variations in TE conversion efficiency and lifetime and the implementation of a circular economy approach for recycling and repurposing TE modules. This suggests that the environmental suitability of TEs is predominantly influenced by the type of fossil energy source they replace, making current TEs unsuitable for stationary applications that periodically generate waste heat. The study also highlights the need for further research on the development of new, practical TEs that utilize nontoxic, abundant elements and are produced through less energy-intensive techniques.
Conversion of Compositionally Diverse Plastic Waste over Earth-Abundant Sulfides
(Journal of the American Chemical Society, 2025-04-02) Selvam, Esun; Schyns, Zoé O. G.; Sun, Jessie A.; Kots, Pavel A.; Kwak, Yeonsu; Korley, LaShanda T. J.; Lobo, Raul F.; Vlachos, Dionisios G.
Chemical deconstruction of polyolefin plastic wastes via hydroconversion is promising for mitigating plastic accumulation in landfills and the environment. However, hydroconversion catalysts cannot handle complex feedstocks containing multiple polymers, additives, and heteroatom impurities. Here, we report a single-step strategy using earth-abundant metal sulfide catalysts to deconstruct these wastes. We show that NiMoSx/HY catalysts deconstruct polyolefin feedstocks, achieving ∼81–94% selectivity to liquid products. Postsynthetic zeolite modification enhances the catalyst’s activity by >2.5 times, achieving over 95% selectivity to liquid fuels with controllable product distribution in the naphtha, jet fuel, and diesel range. The catalyst is resilient to increasingly complex feedstocks, such as additive-containing polymers and mixed plastics composed of polyolefins and heteroatom-containing polymers, including poly(vinyl chloride). We extend the strategy to single-use polyolefin wastes that can generate toxic byproducts, such as HCl and NH3, and eliminate their emissions by integrating reaction and sorption in a one-step process.
The Influence of Irradiation Wavelength on the Growth of Polymer Brushes by SI-PET-RAFT Polymerization
(Journal of Polymer Science, 2025-02-22) Mérai, László; Rymsha, Khrystyna; Yadav, Jyoti; Pester, Christian W.; Fery, Andreas; Besford, Quinn A.
An effective method to produce well-defined polymer brushes with high spatial, temporal, and sequence control is to employ a photoredox catalyst in photo-mediated polymerization. Generally, the excitation wavelength is chosen as the absorption maximum of the photocatalyst, however, it is not clear if that corresponds to the best photochemical activity for producing polymer brushes. Herein, we systematically examine wavelength-by-wavelength resolved polymer brush growth using surface-initiated photoinduced electron transfer-reversible addition-fragmentation chain transfer polymerization (SI-PET-RAFT), of four monomer types. The absorption spectra of the water-soluble photocatalyst (ZnTPPS44−) and the brush growth at each irradiation wavelength were examined as photochemical activity plots. Our results show a striking disparity between the absorbance of the photoredox catalyst and the maximum brush height. Moreover, the photochemical activity with wavelength was highly dependent on the nature of the monomer used. In addition to displaying a strong wavelength selectivity, a characteristic red-shift in the brush height relative to the lowest possible energy transition of the photocatalyst's absorbance spectrum was observed. We anticipate this work will better inform on wavelength choice for SI-PET-RAFT polymerization of polymer brushes. Graphical Abstract available at: https://doi.org/10.1002/pol.20241148 The use of SI-PET-RAFT has been gaining momentum for producing thick, homogenous, functional polymer brushes, in an oxygen-tolerant manner. However, the connection between irradiation wavelength and the brush height has not been clear. Herein, we systematically explore the effect of irradiation wavelength on the resulting brush properties, finding a disconnection between photocatalyst absorption and brush thicknesses.
Toward Sustainable Materials: From Lignocellulosic Biomass to High-Performance Polymers
(Accounts of Materials Research, 2025-02-21) Mahajan, Jignesh S.; Gottlieb, Eric R.; Kim, Jung Min; Epps, Thomas H., III
Conspectus Lignocellulosic biomass is an ideal feedstock for the next generation of sustainable, high-performance, polymeric materials. Although lignin is a highly available and low-cost source of natural aromatics, it is commonly burned for heat or disposed of as waste. The use of lignin for new materials introduces both challenges and opportunities with respect to incumbent petrochemical-based compounds. These considerations are derived from two fundamental aspects of lignin: its recalcitrant/heterogeneous nature and aromatic methoxy substituents. This Account highlights four key efforts from the Epps group and collaborators that established innovative methods/processes to synthesize polymers from lignin deconstruction products to unlock application potential, with a particular focus on the polymerization of biobased monomer mixtures, development of structure–property–processing relationships for diverse feedstocks, functional benefits of methoxy substituents, and scalability of lignin deconstruction. First, lignin-derivable polymethacrylate systems were probed to investigate the polymerization behavior of methacrylate monomers and predict thermomechanical properties of polymers from monomer mixtures. Notably, the glass transition temperatures (Tgs) of lignin-derivable polymethacrylates (∼100–200 °C) were comparable to, or significantly above, those of petroleum-based analogues, such as polystyrene (∼100 °C), and the Tgs of the complex, biobased copolymers could be predicted by the Fox equation prior to biomass deconstruction. Second, an understanding of structure–property relationships in polymethacrylates was applied to create performance-advantaged pressure-sensitive adhesives (PSAs) using phenolic-rich bio-oil obtained from the reductive catalytic fractionation of poplar wood. The use of actual lignin-derived monomers as the starting material was an important step because it underscored that nanostructure-forming, multiblock polymers could be readily made despite the complexity of real lignin deconstruction products. This work also highlighted that lignin-based phenolics could be used to make colorless/odorless PSAs, without complex separations/purifications, and still perform as well as commercial adhesives. Third, an intensified reductive catalytic deconstruction (RCD) process was developed to deconstruct lignin at ambient conditions, and the deconstructed products were successfully employed in 3D printing. The reactive distillation-RCD process operated at ambient pressure using a low-volatility and biobased solvent (glycerin) as a hydrogen donor, which reduced capital/operating costs, energy use, and safety hazards associated with conventional RCD. Technoeconomic analysis showed that such optimization could lead to a 60% reduction in cost to make the PSAs described above. Fourth, lignin-derivable bisguaiacols/bissyringols were explored as potential alternatives to petroleum-derived bisphenol A (BPA) in diamine-cured epoxy resins. A distinguishing feature of the lignin monomers (vs. BPA/bisphenol F [BPF]) was the presence of methoxy groups on the aromatic rings, and these methoxy moieties enabled tuning of application-specific properties, such as Tg, degradation temperature (Td), and glassy storage modulus (E′), to achieve improved processing and performance. The lignin-derivable thermosets exhibited Tgs above 100 °C, Tds above 300 °C, and E′s above 2 GPa, all values that were comparable to those of BPA-/BPF-based analogues. Moreover, the methoxy groups on these lignin-derivable compounds sterically hindered hormone receptor binding and could mitigate many of the toxicity concerns associated with BPA/BPF. This Account concludes with suggestions on future research needed to advance lignin-derived materials as sustainable and performance-advantaged alternatives by leveraging recycling/upcycling strategies and scaling-up/commercializing biomass waste.
Coarse-grained molecular dynamics simulations of mixtures of polysulfamides
(RSC Applied Polymers, 2025-02-20) Shah, Jay; Jayaraman, Arthi
Polysulfamides are a new class of polymers that exhibit favorable chemical and physical properties, making them a sustainable alternative to commodity polymers like polyurea. To advance the fundamental understanding of this new class of polymers, Wu et al. [Z. Wu, J. W. Wu, Q. Michaudel and A. Jayaraman, Macromolecules, 2023, 56, 5033–5049]conducted experiments and coarse-grained (CG) molecular dynamics (MD) simulations to connect the polysulfamide backbone design to the assembled structure of polysulfamides due to hydrogen bonding between sulfamides. Their CG MD simulations qualitatively reproduced experimentally observed trends in crystallinity for analogous variations in polysulfamide backbone designs. To bring chemical specificity to this generic CG model of Wu et al. and to facilitate quantitative agreement with experiments in the future, in this work, we modify this older CG model of Wu et al. using structural information from atomistic simulations. Atomistic angle and dihedral distributions involving the sulfamide functional groups are used to modify the donor and acceptor bead positions in the new CG model. Using MD simulations with this new atomistically informed CG model, we confirm that we obtained the structural trends with varying polysulfamide backbone length, bulkiness, and non-uniformity of the segments in repeat units as seen in the previous work by Wu et al. These key structural trends are as follows: (a) shorter contour lengths of segments between sulfamide groups enhance H-bonding between sulfamides, (b) increased bulkiness in the segment hinders sulfamide–sulfamide H-bonding and reduces orientational order among chains in the assembled structure, and (c) non-uniformity in the segments along the backbone does not affect orientational order in the assembled structure. While the trends qualitatively matched between the two models, we observe quantitatively higher positional order and lower orientational order among the assembled chains in the new CG model as compared to the older CG model. This difference in local chain packing arises from a change in the donor–acceptor H-bonding pattern between the two models. In this work, we also use the new CG model to study mixing and demixing in two types of mixtures of polysulfamides: one mixture has chains with varying segment lengths between sulfamide groups and another mixture has chains with different degrees of bulkiness in the backbone. We find that increasing dissimilarity (bulkiness or length) between the two types of chains promotes demixing despite the presence of sulfamide–sulfamide H-bonding interactions.
Molecular-Scale Simulation of Wetting of Actin Filaments by Protein Droplets
(The Journal of Physical Chemistry B, 2025-01-12) Andrews, James; Weirich, Kimberly; Schiller, Ulf D.
Liquid phase-separating proteins can form condensates that play an important role in spatial and temporal organization of biological cells. The understanding of the mechanisms that lead to the formation of protein condensates and their interactions with other biomolecules may lead to processing routes for soft materials with tailored geometry and function. Fused in sarcoma (FUS) is an example of a nuclear protein that forms stable complexes, and recent studies have highlighted its ability to wet actin filaments and bundle them into networks. We perform coarse-grained molecular dynamics simulations to investigate the wetting and spreading of FUS droplets on actin filaments. We employ the Martini model and rescale the protein–protein and protein–actin interactions to tune the interfacial and wetting properties of FUS droplets. By measuring the molecular displacements in the three-phase region, we are able to relate contact angle, contact line velocity, and contact line friction in terms of a linear approximation of molecular kinetic theory. The results show that the rescaled Martini model can be used to study the molecular mechanisms of dynamic wetting at the nanoscale and to obtain quantitative predictions of the contact line friction and contact angles during dynamic wetting.
Further exploration of the physicochemical nature of μ2-bridge-relevant deprotonations via the elucidation of four kinds of alditol complexes
(Physical Chemistry Chemical Physics, 2024-12-12) Wu, Yi; Xie, Linchen; Jiang, Ye; He, Anqi; Li, Da; Yang, Limin; Xu, Yizhuang; Liu, Kexin; Ozaki, Yukihiro; Noda, Isao
Single-crystal structures of four alditol complexes are presented. In LuCl3/galactitol and ScCl3/myo-inositol complexes, μ2-bridge-relevant deprotonations were observed. The polarization from two rare earth ions in the μ2-bridge activates the chemically inert OH and promotes deprotonation. Additionally, mass spectrometry, pH experiments, and quantum chemistry calculations were conducted to enhance our understanding of the μ2-bridge-relevant deprotonations. A common structural feature of the complexes where μ2-bridge-relevant deprotonation takes place is that two metal ions and two oxygen atoms in two μ2-bridges form an M2O2 cluster. The four atoms in the M2O2 cluster make up a parallelogram. Such a structure is useful to balance the strong coulombic repulsions between two M3+ and between two O−. In the ScCl3/myo-inositol complex, the deprotonation exhibits a characteristic of regional/chiral selectivity. Galactitol is a third alditol ligand where μ2-bridge-relevant deprotonation is observed. The flexible backbone of the galactitol allows the formation of more five-membered chelating rings and six-membered chelating rings, which are used to stabilize the rare earth ions of the μ2-bridge. The coordination makes the backbone of galactitol deviate from the zigzag conformation. The above results are helpful in the rational design of high-performance catalysts.
A bio-inspired approach to engineering water-responsive, mechanically-adaptive materials
(Molecular Systems Design & Engineering, 2025-02-20) Jang, Daseul; Wong, Yu-Tai; Korley, LaShanda T. J.
Inspired by a diverse array of hierarchical structures and mechanical function in spider silk, we leverage building blocks that can form non-covalent interactions to develop mechanically-tunable and water-responsive composite materials via hydrogen bonding modulation. Specifically, self-assembling peptide blocks consisting of poly(β-benzyl-l-aspartate) (PBLA) are introduced into a hydrophilic polyurea system. Using these peptide–polyurea hybrids (PPUs) as a hierarchical matrix, cellulose nanocrystals (CNCs) are incorporated to diversify the self-assembled nanostructures of PPUs through matrix–filler interactions. Our findings reveal that higher PBLA content in the PPUs reduces the magnitude of the stiffness differential due to the physical crosslinking induced by the peptide blocks. Additionally, the inclusion of CNCs in the PPU matrix increases the storage modulus in the dry state but also diminishes the wet-state modulus due to the shift of physical associations from peptidic arrangements to PBLA–CNC interactions, resulting in variations in the morphology of the PPU/CNC nanocomposites. This molecular design strategy allows for the development of adaptable materials with a broad range of water-responsive storage modulus switching , spanning from ∼70 MPa to ∼400 MPa. This investigation highlights the potential of harnessing peptide assembly and peptide–cellulose interactions to achieve mechanical enhancement and water-responsiveness, providing insights for engineering next-generation responsive materials.
Standard purification methods are not sufficient to remove micellular lipophilic dye from polymer nanoparticle solution
(RSC Pharmaceutics, 2025-03-06) Sterin, Eric H.; Weinstein, Laura A.; Chowdhury, Chitran Roy; Guzzetti, Emma C.; Day, Emily S.
Tracking nanoparticles’ location is imperative for understanding cellular interactions, pharmacokinetics, and biodistribution. DiD is a lipophilic dye commonly used to label nanoparticles for trafficking studies. Herein, we show that DiD micelles form in polymer NP solutions during synthesis and can lead to false positive results in downstream assays. Potential methods to remove these micelles are also described.
Non-Isothermal Melt Crystallization of a Biodegradable Polymer Studied by Two-Dimensional Infrared Correlation Spectroscopy
(Molecules, 2025-03-01) Noda, Isao
The non-isothermal melt crystallization process of poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoateate] (PHBHx) was monitored using attenuated total reflection infrared (ATR IR) measurement. The resulting time- and temperature-dependent spectra were subjected to the two-dimensional correlation spectroscopy (2D-COS) analysis. The C=O stretching region of the PHBHx sample consisted of several distinct IR contributions attributable to the population of amorphous component, well-ordered type I lamellar crystal, and less ordered inter-lamellar type II crystal. The spectral intensity change in type I crystal occurs in the earlier stage of the crystallization at a higher temperature range compared to the overall intensity decrease in the amorphous component occurring throughout the crystallization process. The growth of the type II crystal started in a later stage at a lower temperature than the creation of the type I crystal. An early decrease in a small but distinct portion of the amorphous component may be related to a crystallization precursor species with some level of molecular order. Hetero-mode correlation analyses revealed that the crystalline band intensity changes in the C-H stretching and fingerprint regions all occur later than the population changes in crystalline species reflected by the carbonyl stretching bands. This observation suggests that the spectral intensity changes in the C-H stretching and fingerprint regions do not directly represent the population dynamics of the crystalline and amorphous species but probe instead the molecular state of the crystalline entities still undergoing the evolutionary changes.
Ordered assemblies of peptide nanoparticles with only positive charge
(Nature Communications, 2024-11-20) Shi, Yi; Zhang, Tianren; Guo, Rui; Zhang, Zihan; McCahill, Amanda L.; Tang, Yao; Liskey, Sabrina E.; Yang, Dai-Bei; Kloxin, Christopher J.; Saven, Jeffery G.; Pochan, Darrin J.
Surface charge patchiness of different charge types can influence the solution behaviours of colloidal particles and globular proteins. Herein, coiled-coil ‘bundlemer’ nanoparticles that display only a single type of surface charge (SC) are computationally designed to compare their solution behaviours to mixed charge-type (MC) counterparts with both positively and negatively charged side chains. Nematic and columnar liquid crystal phases are discovered in low concentrations of SC particles, indicative of particle end-to-end stacking into columns combined with lateral electrostatic repulsion between columns, while MC particles with the same net charge and particle shape produced only amorphous, soluble aggregates. Similarly, porous lattices are formed in mixtures of SC/MC particles of opposite charges while MC/MC mixtures of opposite charges produce only amorphous aggregates. The lattice structure is inferred with a machine learning optimization approach. The differences between SC and MC particle behaviours directly show the importance of surface electrostatic patchiness.

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