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Gharibi A, Eslami H, Müller-Plathe F. Self-Assembly of Model Three- and Four-Patch Colloidal Particles in Two Dimensions. J Chem Theory Comput 2024. [PMID: 39066701 DOI: 10.1021/acs.jctc.4c00540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
A coarse-grained effective solvent model of two-patch particles is extended to study the self-assembly of three- and four-patch particles to two-dimensional honeycomb and square lattices, respectively. Employing this model, grand canonical ensemble simulations are done to calculate vapor-liquid equilibria and the critical temperatures for patchy particles of various patch widths. The range of stability of the liquid, although very limited compared to isotropic particles, which interact through a longer-range potential, depends on the patch width and on the number of patches. Biased sampling and unbiased simulations are also done to investigate the mechanism of nucleation and crystal growth for honeycomb and square lattices, self-assembled from three- and four-patch particles, respectively. A two-step mechanism governs the nucleation of both lattices. In the first step, the particles form a dense amorphous network, and in the second step, the particles inside the amorphous network reorient to form crystalline nuclei. Barrier heights for the nucleation of honeycomb and square lattices are 7.8 kBT and 7.4 kBT, which are close to the reported values for the nucleation of the kagome lattice. In agreement with confocal microscopy experiments, the self-assembly in a honeycomb lattice involves the formation of 5- to 7-membered rings. The 5- and 7-membered rings hamper the nucleation of the honeycomb lattice, through defect formation and rotation of the symmetry planes of crystals that form at their surfaces. With the progress of self-assembly, a substantial amount of restructuring of the defects and crystals in their vicinity is needed to heal the defects.
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Affiliation(s)
- Ali Gharibi
- Department of Chemistry, College of Sciences, Persian Gulf University, Boushehr 75168, Iran
| | - Hossein Eslami
- Department of Chemistry, College of Sciences, Persian Gulf University, Boushehr 75168, Iran
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Peter-Grünberg-Straße 8, 64287 Darmstadt, Germany
| | - Florian Müller-Plathe
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Peter-Grünberg-Straße 8, 64287 Darmstadt, Germany
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Eslami H, Müller-Plathe F. Self-Assembly Pathways of Triblock Janus Particles into 3D Open Lattices. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2306337. [PMID: 37990935 DOI: 10.1002/smll.202306337] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 10/20/2023] [Indexed: 11/23/2023]
Abstract
The self-assembly of triblock Janus particles is simulated from a fluid to 3D open lattices: pyrochlore, perovskite, and diamond. The coarse-grained model explicitly takes into account the chemical details of the Janus particles (attractive patches at the poles and repulsion around the equator) and it contains explicit solvent particles. Hydrodynamic interactions are accounted for by dissipative particle dynamics. The relative stability of the crystals depends on the patch width. Narrow, intermediate, and wide patches stabilize the pyrochlore-, the perovskite-, and the diamond-lattice, respectively. The nucleation of all three lattices follows a two-step mechanism: the particles first agglomerate into a compact and disordered liquid cluster, which does not crystallize until it has grown to a threshold size. Second, the particles reorient inside this cluster to form crystalline nuclei. The free-energy barriers for the nucleation of pyrochlore and perovskite are ≈10 kBT, which are close to the nucleation barriers of previously studied 2D kagome lattices. The barrier height for the nucleation of diamond, however, is much larger (>20 kBT), as the symmetry of the triblock Janus particles is not perfect for a diamond structure. The large barrier is associated with the reorientation of particles, i.e., the second step of the nucleation mechanism.
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Affiliation(s)
- Hossein Eslami
- Department of Chemistry, College of Sciences, Persian Gulf University, Boushehr, 75168, Iran
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Peter-Grünberg-Straße 8, 64287, Darmstadt, Germany
| | - Florian Müller-Plathe
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Peter-Grünberg-Straße 8, 64287, Darmstadt, Germany
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Yellam K, Priyadarshi A, Jha PK. Monte Carlo simulations of spherocylinders interacting with site-dependent square-well potentials. Sci Rep 2024; 14:3753. [PMID: 38355955 PMCID: PMC10866863 DOI: 10.1038/s41598-024-53182-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 01/29/2024] [Indexed: 02/16/2024] Open
Abstract
Monte Carlo simulations are performed to study the self-assembly of a dilute system of spherocylinders interacting with square-well potential. The interactions are defined between randomly placed sites on the axis of the spherocylinder, akin to the interacting groups on a rigid rodlike molecule. This model therefore also serves as a minimal coarse-grained representation of a system of low molecular weight or stiff polymers with contour lengths significantly lower than the persistence length, interacting predominantly with short-range interactions (e.g., hydrogen bonding). The spherocylinder concentration, square-well interaction strength and range, and fraction of interacting sites are varied to study the phase behavior of the system. We observe the formation of dispersed, bundled, and network configurations of the system that may be compared with previous atomistic simulation results of weak polyelectrolytes.
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Affiliation(s)
- Kiranmai Yellam
- Department of Chemical Engineering, IIT Roorkee, Roorkee, Uttarakhand, 247667, India
| | - Anshuman Priyadarshi
- Department of Chemical Engineering, IIT Roorkee, Roorkee, Uttarakhand, 247667, India
| | - Prateek K Jha
- Department of Chemical Engineering, IIT Roorkee, Roorkee, Uttarakhand, 247667, India.
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Ji Y, Zhao H, Liu H, Zhao P, Yu DG. Electrosprayed Stearic-Acid-Coated Ethylcellulose Microparticles for an Improved Sustained Release of Anticancer Drug. Gels 2023; 9:700. [PMID: 37754381 PMCID: PMC10528259 DOI: 10.3390/gels9090700] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 08/21/2023] [Accepted: 08/26/2023] [Indexed: 09/28/2023] Open
Abstract
Sustained release is highly desired for "efficacious, safe and convenient" drug delivery, particularly for those anticancer drug molecules with toxicity. In this study, a modified coaxial electrospraying process was developed to coat a hydrophobic lipid, i.e., stearic acid (SA), on composites composed of the anticancer drug tamoxifen citrate (TC) and insoluble polymeric matrix ethylcellulose (EC). Compared with the electrosprayed TC-EC composite microparticles M1, the electrosprayed SA-coated hybrid microparticles M2 were able to provide an improved TC sustained-release profile. The 30% and 90% loaded drug sustained-release time periods were extended to 3.21 h and 19.43 h for M2, respectively, which were significantly longer than those provided by M1 (0.88 h and 9.98 h, respectively). The morphology, inner structure, physical state, and compatibility of the components of the particles M1 and M2 were disclosed through SEM, TEM, XRD, and FTIR. Based on the analyses, the drug sustained-release mechanism of multiple factors co-acting for microparticles M2 is suggested, which include the reasonable selections and organizations of lipid and polymeric excipient, the blank SA shell drug loading, the regularly round shape, and also the high density. The reported protocols pioneered a brand-new manner for developing sustained drug delivery hybrids through a combination of insoluble cellulose gels and lipid using modified coaxial electrospraying.
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Affiliation(s)
- Yuexin Ji
- School of Materials and Chemistry, University of Shanghai for Science and Technology, No. 516 Jungong Road, Shanghai 200093, China; (Y.J.); (H.L.); (P.Z.)
| | - Hua Zhao
- Medical School, Quzhou College of Technology, No. 18 Jiangyuan Road, Quzhou 324000, China
| | - Hui Liu
- School of Materials and Chemistry, University of Shanghai for Science and Technology, No. 516 Jungong Road, Shanghai 200093, China; (Y.J.); (H.L.); (P.Z.)
| | - Ping Zhao
- School of Materials and Chemistry, University of Shanghai for Science and Technology, No. 516 Jungong Road, Shanghai 200093, China; (Y.J.); (H.L.); (P.Z.)
| | - Deng-Guang Yu
- School of Materials and Chemistry, University of Shanghai for Science and Technology, No. 516 Jungong Road, Shanghai 200093, China; (Y.J.); (H.L.); (P.Z.)
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Bi P, Zhu X, Han J, Tian L, Zhang W. Synthesis and Comparative Study of Polyether- b-polybutadiene- b-polyether Triblock Copolymers for Use as Polyurethanes. Polymers (Basel) 2023; 15:3486. [PMID: 37631543 PMCID: PMC10459386 DOI: 10.3390/polym15163486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 07/31/2023] [Accepted: 08/01/2023] [Indexed: 08/27/2023] Open
Abstract
In this paper, the effects of HTPBs with different main-chain microstructures on their triblock copolymers and polyurethane properties were investigated. Three polyether-modified HTPB triblock copolymers were successfully synthesized via a cationic ring-opening copolymerization reaction using three HTPBs with different microstructures prepared via three different polymerization methods as the macromolecular chain transfer agents and tetrahydrofuran (THF) and propylene oxide (PO) as the copolymerization monomers. Finally, the corresponding polyurethane elastomers were prepared using the three triblock copolymers as soft segments and toluene diisocyanate (TDI) as hard segments. The results of an analysis of the triblock copolymers showed that the triblock copolymers had lower viscosity and glass transition temperature (Tg) values as the HTPB 1,2 structure content decreased, although the effect on the thermal decomposition temperature was not significant. An analysis of the polyurethane elastomers revealed that as the content of the 1,2 structure in HTPB increased, its corresponding polyurethane elastomers showed a gradual increase in breaking strength and a gradual decrease in elongation at break. In addition, PU-1 had stronger crystallization properties compared to PU-2 and PU-3. However, the differences in the microstructures of the HTPBs did not seem to have much effect on the surface properties of the polyurethane elastomers.
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Affiliation(s)
- Pengzhi Bi
- State Key Laboratory of Biobased Material and Green Papermaking, Key Laboratory of Pulp and Paper Science & Technology of Ministry of Education, Faculty of Light Industry, Shandong Academy of Sciences, Qilu University of Technology, Jinan 250353, China; (P.B.); (J.H.); (L.T.)
- Key Laboratory for Green Leather Manufacture Technology of China National Light Industry Council, Faculty of Light Industry, Shandong Academy of Sciences, Qilu University of Technology, Jinan 250353, China
| | - Xiuzhong Zhu
- State Key Laboratory of Biobased Material and Green Papermaking, Key Laboratory of Pulp and Paper Science & Technology of Ministry of Education, Faculty of Light Industry, Shandong Academy of Sciences, Qilu University of Technology, Jinan 250353, China; (P.B.); (J.H.); (L.T.)
- Key Laboratory for Green Leather Manufacture Technology of China National Light Industry Council, Faculty of Light Industry, Shandong Academy of Sciences, Qilu University of Technology, Jinan 250353, China
- Key Laboratory of Auxiliary Chemistry and Technology for Chemical Industry Ministry of Education, Shaanxi Collaborative Innovation Center of Industrial Auxiliary Chemistry and Technology, Shaanxi University of Science and Technology, Xi’an 710021, China;
| | - Jinbang Han
- State Key Laboratory of Biobased Material and Green Papermaking, Key Laboratory of Pulp and Paper Science & Technology of Ministry of Education, Faculty of Light Industry, Shandong Academy of Sciences, Qilu University of Technology, Jinan 250353, China; (P.B.); (J.H.); (L.T.)
- Key Laboratory for Green Leather Manufacture Technology of China National Light Industry Council, Faculty of Light Industry, Shandong Academy of Sciences, Qilu University of Technology, Jinan 250353, China
| | - Li Tian
- State Key Laboratory of Biobased Material and Green Papermaking, Key Laboratory of Pulp and Paper Science & Technology of Ministry of Education, Faculty of Light Industry, Shandong Academy of Sciences, Qilu University of Technology, Jinan 250353, China; (P.B.); (J.H.); (L.T.)
- Key Laboratory for Green Leather Manufacture Technology of China National Light Industry Council, Faculty of Light Industry, Shandong Academy of Sciences, Qilu University of Technology, Jinan 250353, China
| | - Wanbin Zhang
- Key Laboratory of Auxiliary Chemistry and Technology for Chemical Industry Ministry of Education, Shaanxi Collaborative Innovation Center of Industrial Auxiliary Chemistry and Technology, Shaanxi University of Science and Technology, Xi’an 710021, China;
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Hernández Velázquez JD, Sánchez-Balderas G, Gama Goicochea A, Pérez E. The effective interfacial tensions between pure liquids and rough solids: a coarse-grained simulation study. Phys Chem Chem Phys 2023; 25:10325-10334. [PMID: 36987944 DOI: 10.1039/d2cp04321a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
The effective solid-liquid interfacial tension (SL-IFT) between pure liquids and rough solid surfaces is studied through coarse-grained simulations. Using the dissipative particle dynamics method, we design solid-liquid interfaces, confining a pure liquid between two explicit solid surfaces with different roughness degrees. The roughness of the solid phase is characterized by Wenzel's roughness factor and the effective SL-IFT is reported as a function of it also. Two solid-liquid systems, different from each other by their solid-liquid repulsion strength, are studied to measure the effects caused by the surface roughness on the calculation of . It is found that the roughness changes the structure of the liquid, which is observed in the first layer of liquid near the solid. These changes are responsible for the effective SL-IFT increase, as surface roughness increases. Although there is a predominance of surface roughness in the calculation of it is found that the effective SL-IFT is directly proportional to the magnitude of the solid-liquid repulsion strength. The insights provided by these simulations suggest that the increase of Wenzel's roughness factor increases the number of effective solid-liquid interactions between particles, yielding significant changes in the local values of the normal and tangential components of the pressure tensor.
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Affiliation(s)
- J D Hernández Velázquez
- División de Ingeniería Química y Bioquímica, Tecnológico de Estudios Superiores de Ecatepec, 55210, Ecatepec de Morelos, Estado de México, Mexico.
| | - G Sánchez-Balderas
- Instituto de Física, Universidad Autónoma de San Luis Potosí, 78000, San Luis Potosí, SLP, Mexico.
| | - A Gama Goicochea
- División de Ingeniería Química y Bioquímica, Tecnológico de Estudios Superiores de Ecatepec, 55210, Ecatepec de Morelos, Estado de México, Mexico.
| | - E Pérez
- Instituto de Física, Universidad Autónoma de San Luis Potosí, 78000, San Luis Potosí, SLP, Mexico.
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Matouk Z, Islam M, Gutiérrez M, Pireaux JJ, Achour A. X-ray Photoelectron Spectroscopy (XPS) Analysis of Ultrafine Au Nanoparticles Supported over Reactively Sputtered TiO 2 Films. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:3692. [PMID: 36296882 PMCID: PMC9609015 DOI: 10.3390/nano12203692] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 10/06/2022] [Accepted: 10/10/2022] [Indexed: 06/16/2023]
Abstract
The impact of a titania (TiO2) support film surface on the catalytic activity of gold nanoparticles (Au NP) was investigated. Using the reactive dc-magnetron sputtering technique, TiO2 films with an amorphous, anatase, and nitrogen-doped anatase crystal structure were produced for a subsequent role as a support material for Au NP. Raman spectra of these TiO2 films revealed that both vacuum and NH3 annealing treatments promoted amorphous to anatase phase transformation through the presence of a peak in the 513-519 cm-1 spectral regime. Furthermore, annealing under NH3 flux had an associated blue shift and broadening of the Raman active mode at 1430 cm-1, characteristic of an increase in the oxygen vacancies (VO). For a 3 to 15 s sputter deposition time, the Au NP over TiO2 support films were in the 6.7-17.1 nm size range. From X-ray photoelectron spectroscope (XPS) analysis, the absence of any shift in the Au 4f core level peak implied that there was no change in the electronic properties of Au NP. On the other hand, spontaneous hydroxyl (-OH) group adsorption to anatase TiO2 support was instantly detected, the magnitude of which was found to be enhanced upon increasing the Au NP loading. Nitrogen-doped anatase TiO2 supporting Au NP with ~21.8 nm exhibited a greater extent of molecular oxygen adsorption. The adsorption of both -OH and O2 species is believed to take place at the perimeter sites of the Au NP interfacing with the TiO2 film. XPS analyses and discussions about the tentative roles of O2 and -OH adsorbent species toward Au/TiO2 systems corroborate very well with interpretations of density functional theory simulations.
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Affiliation(s)
- Zineb Matouk
- Technology Innovation Institute, Abu Dhabi P.O. Box 9639, United Arab Emirates
| | - Mohammad Islam
- GE Aerospace, 3290 Patterson Ave SE, Grand Rapids, MI 49512, USA
| | - Monserrat Gutiérrez
- Technology Innovation Institute, Abu Dhabi P.O. Box 9639, United Arab Emirates
| | - Jean-Jacques Pireaux
- Research Centre, Physics of Matter and Radiation (PMR), LISE Laboratory, University of Namur, B-5000 Namur, Belgium
| | - Amine Achour
- Pixium Vision S.A. 74 Rue du FGB Saint-Antoine, 75012 Paris, France
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Yin F, Yang L, Hou W, Yuan Y, Yu H. Study of dielectric properties of meta-aramid fibers by molecular dynamics methods using modified OPLSAA force field. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.125331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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9
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Bhavani R, Kanagathara N, Marchewka M, Janczak J. Structural and spectroscopic characterization of the products formed in aqueous solution of hydrazine and maleic acid. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.134077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Wang Y, Zhang YY, Liao XH, Yin BB, Zhao Y, Gao NN, Jiang H, Mao DR, Yang YX. Multi-responsive luminescent MOF sensor for Fe3+, CrO42− and Cr2O72− in aqueous solution based on phenylenediacetate and bis-imidazole ligand. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.133239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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11
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Heczko D, Hachuła B, Maksym P, Kamiński K, Zięba A, Orszulak L, Paluch M, Kamińska E. The Effect of Various Poly ( N-vinylpyrrolidone) (PVP) Polymers on the Crystallization of Flutamide. Pharmaceuticals (Basel) 2022; 15:971. [PMID: 36015118 PMCID: PMC9414356 DOI: 10.3390/ph15080971] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 08/01/2022] [Accepted: 08/03/2022] [Indexed: 11/16/2022] Open
Abstract
In this study, several experimental techniques were applied to probe thermal properties, molecular dynamics, crystallization kinetics and intermolecular interactions in binary mixtures (BMs) composed of flutamide (FL) and various poly(N-vinylpyrrolidone) (PVP) polymers, including a commercial product and, importantly, samples obtained from high-pressure syntheses, which differ in microstructure (defined by the tacticity of the macromolecule) from the commercial PVP. Differential Scanning Calorimetry (DSC) studies revealed a particularly large difference between the glass transition temperature (Tg) of FL+PVPsynth. mixtures with 10 and 30 wt% of the excipient. In the case of the FL+PVPcomm. system, this effect was significantly lower. Such unexpected findings for the former mixtures were strictly connected to the variation of the microstructure of the polymer. Moreover, combined DSC and dielectric measurements showed that the onset of FL crystallization is significantly suppressed in the BM composed of the synthesized polymers. Further non-isothermal DSC investigations carried out on various FL+10 wt% PVP mixtures revealed a slowing down of FL crystallization in all FL-based systems (the best inhibitor of this process was PVP Mn = 190 kg/mol). Our research indicated a significant contribution of the microstructure of the polymer on the physical stability of the pharmaceutical-an issue completely overlooked in the literature.
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Affiliation(s)
- Dawid Heczko
- Department of Pharmacognosy and Phytochemistry, Faculty of Pharmaceutical Sciences in Sosnowiec, Medical University of Silesia in Katowice, 41-200 Sosnowiec, Poland
| | - Barbara Hachuła
- Institute of Chemistry, Faculty of Science and Technology, University of Silesia in Katowice, 40-007 Katowice, Poland
| | - Paulina Maksym
- Institute of Material Science, Faculty of Science and Technology, University of Silesia in Katowice, 41-500 Chorzów, Poland
| | - Kamil Kamiński
- Institute of Physics, Faculty of Science and Technology, University of Silesia in Katowice, 41-500 Chorzów, Poland
| | - Andrzej Zięba
- Department of Organic Chemistry, Faculty of Pharmaceutical Sciences in Sosnowiec, Medical University of Silesia in Katowice, 41-200 Sosnowiec, Poland
| | - Luiza Orszulak
- Institute of Chemistry, Faculty of Science and Technology, University of Silesia in Katowice, 40-007 Katowice, Poland
| | - Marian Paluch
- Institute of Physics, Faculty of Science and Technology, University of Silesia in Katowice, 41-500 Chorzów, Poland
| | - Ewa Kamińska
- Department of Pharmacognosy and Phytochemistry, Faculty of Pharmaceutical Sciences in Sosnowiec, Medical University of Silesia in Katowice, 41-200 Sosnowiec, Poland
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Supramolecular Self-Assembly of Dipalmitoylphosphatidylcholine and Carbon Nanotubes: A Dissipative Particle Dynamics Simulation Study. NANOMATERIALS 2022; 12:nano12152653. [PMID: 35957084 PMCID: PMC9370663 DOI: 10.3390/nano12152653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 07/26/2022] [Accepted: 08/01/2022] [Indexed: 11/21/2022]
Abstract
Dissipative particle dynamics simulations were performed to investigate the self-assembly of dipalmitoylphosphatidylcholine (DPPC) as a model lipid membrane on the surface of carbon nanotubes (CNTs). The influence of surface curvature of CNTs on self-assembly was investigated by performing simulations on solutions of DPPC in water in contact with CNTs of different diameters: CNT (10, 10), CNT (14, 14), CNT (20, 20), and CNT (34, 34). DPPC solutions with a wide range of concentrations were chosen to allow for formation of lipid structures of various surface densities, ranging from a submonolayer to a well-organized monolayer and a CNT covered with a lipid monolayer immersed in a planar lipid bilayer. Our results are indicative of a sequence of phase-ordering processes for DPPC on the surface of CNTs. At low surface coverages, the majority of hydrocarbon tail groups of DPPC are in contact with the CNT surface. Increasing the surface coverage leads to the formation of hemimicellar aggregates, and at high surface coverages close to the saturation limit, an organized lipid monolayer self-assembles. An examination of the mechanism of self-assembly reveals a two-step mechanism. The first step involves densification of DPPC on the CNT surface. Here, the lipid molecules do not adopt the order of the target phase (lipid monolayer on the CNT surface). In the second step, when the lipid density on the CNT surface is above a threshold value (close to saturation), the lipid molecules reorient themselves to form an organized monolayer around the tube. Here, the DPPC molecules adopt stretched conformations normal to the surface, the end hydrocarbon groups adsorb on the surface, and the head groups occupy the outermost part of the monolayer. The saturation density and the degree of lipid ordering on the CNT surface depend on the surface curvature. The saturation density increases with increased surface curvature, and better-ordered structures are formed on less curved surfaces.
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Hu N, Wang Y, Ma R, Zhang W, Li B, Zhao X, Zhang L, Gao Y. Optimizing the fracture toughness of a dual cross-linked hydrogel via molecular dynamics simulation. Phys Chem Chem Phys 2022; 24:17605-17614. [PMID: 35829708 DOI: 10.1039/d2cp02478k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this work, a coarse-grained model is adopted to explore the fracture toughness of a dual cross-linked hydrogel which consists of a physically cross-linked network and a chemically cross-linked network. By calculating the fracture energy, the optimized fracture toughness of the hydrogel appears at the intermediate content of the chemical network. To understand it, the structure change of both the chemical network and the physical network is first characterized during the tensile process. For the chemical network, the fraction and rate of broken bonds gradually improve with increasing content of the chemical network while the strain range where the bond breakage occurs is reduced. For the physical network, the number of clusters and the interaction energy first increase and then decrease with increasing strain. This reflects the breakage and reformation of the physical network, which dissipates more energy and improves the fracture energy. Furthermore, by stress decomposition, the stress is mainly borne by the physical network at small strain and the chemical network at large strain, which proves their synergistic effect in enhancing the hydrogel. Then, the number of voids is calculated as a function of strain. It is found that the voids initiate in the weak region at small strain while in the position of the bond breakage at large strain. Moreover, the number of voids decreases with increasing content of the chemical network at small strain. Finally, the effect of the strength of the chemical network or the physical network on the fracture toughness is discussed. The optimized fracture toughness of hydrogel appears at the intermediate strength.
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Affiliation(s)
- Nan Hu
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, 10029, People's Republic of China. .,Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 10029, People's Republic of China.
| | - Yimin Wang
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, 10029, People's Republic of China. .,Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 10029, People's Republic of China.
| | - Ruibin Ma
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, 10029, People's Republic of China. .,Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 10029, People's Republic of China.
| | - Wenfeng Zhang
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, 10029, People's Republic of China. .,Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 10029, People's Republic of China.
| | - Bin Li
- School of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai 519082, People's Republic of China
| | - Xiuying Zhao
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, 10029, People's Republic of China. .,Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 10029, People's Republic of China.
| | - Liqun Zhang
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, 10029, People's Republic of China. .,Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 10029, People's Republic of China.
| | - Yangyang Gao
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, 10029, People's Republic of China. .,Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, 10029, People's Republic of China.
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Liu J, Song W, Ma G, Li K. Faraday Instability in Viscous Fluids Covered with Elastic Polymer Films. Polymers (Basel) 2022; 14:polym14122334. [PMID: 35745910 PMCID: PMC9231276 DOI: 10.3390/polym14122334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 06/06/2022] [Accepted: 06/07/2022] [Indexed: 02/05/2023] Open
Abstract
Faraday instability has great application value in the fields of controlling polymer processing, micromolding colloidal lattices on structured suspensions, organizing particle layers, and conducting cell culture. To regulate Faraday instability, in this article, we attempt to introduce an elastic polymer film covering the surface of a viscous fluid layer and theoretically study the behaviors of the Faraday instability phenomenon and the effect of the elastic polymer film. Based on hydrodynamic theory, the Floquet theory is utilized to formulate its stability criterion, and the critical acceleration amplitude and critical wave number are calculated numerically. The results show that the critical acceleration amplitude for Faraday instability increases with three increasing bending stiffness of the elastic polymer film, and the critical wave number decreases with increasing bending stiffness. In addition, surface tension and viscosity also have important effects on the critical acceleration amplitude and critical wave number. The strategy of controlling Faraday instability by covering an elastic polymer film proposed in this paper has great application potential in new photonic devices, metamaterials, alternative energy, biology, and other fields.
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Affiliation(s)
- Junxiu Liu
- Anhui Province Key Laboratory of Building Structure and Underground Engineering, Anhui Jianzhu University, Hefei 230601, China;
- College of Civil Engineering, Anhui Jianzhu University, Hefei 230601, China; (W.S.); (G.M.)
| | - Wenqiang Song
- College of Civil Engineering, Anhui Jianzhu University, Hefei 230601, China; (W.S.); (G.M.)
| | - Gan Ma
- College of Civil Engineering, Anhui Jianzhu University, Hefei 230601, China; (W.S.); (G.M.)
| | - Kai Li
- Anhui Province Key Laboratory of Building Structure and Underground Engineering, Anhui Jianzhu University, Hefei 230601, China;
- College of Civil Engineering, Anhui Jianzhu University, Hefei 230601, China; (W.S.); (G.M.)
- Correspondence:
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15
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Ferrocene based ionic liquid: synthesis, structure, transport properties and mechanism of thermal degradation. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.118933] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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16
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Zhou T, Wu Z, Das S, Eslami H, Müller-Plathe F. How Ethanolic Disinfectants Disintegrate Coronavirus Model Membranes: A Dissipative Particle Dynamics Simulation Study. J Chem Theory Comput 2022; 18:2597-2615. [PMID: 35286098 PMCID: PMC8938819 DOI: 10.1021/acs.jctc.1c01120] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Indexed: 01/03/2023]
Abstract
We have developed dissipative particle dynamics models for pure dipalmitoylphosphatidylcholine (DPPC), dioleoylphosphatidylcholine (DOPC), and dimyristoylphosphatidylcholine (DMPC) as well as their binary and ternary mixed membranes, as coronavirus model membranes. The stabilities of pure and mixed membranes, surrounded by aqueous solutions containing up to 70 mol % ethanol (alcoholic disinfectants), have been investigated at room temperature. We found that aqueous solutions containing 5-10 mol % ethanol already have a significant weakening effect on the pure and mixed membranes. The magnitude of the effect depends on the membrane composition and the ethanol concentration. Ethanol permeabilizes the membrane, causing its lateral swelling and thickness shrinking and reducing the orientational order of the hydrocarbon tail of the bilayer. The free energy barrier for the permeation of ethanol in the bilayers is considerably reduced by the ethanol uptake. The rupture-critical ethanol concentrations causing the membrane failure are 20.7, 27.5, and 31.7 mol % in the aqueous phase surrounding pure DMPC, DOPC, and DPPC membranes, respectively. Characterizing the failure of lipid membranes by a machine-learning neural network framework, we found that all mixed binary and/or ternary membranes disrupt when immersed in an aqueous solution containing a rupture-critical ethanol concentration, ranging from 20.7 to 31.7 mol %, depending on the composition of the membrane; the DPPC-rich membranes are more intact, while the DMPC-rich membranes are least intact. Due to the tight packing of long, saturated hydrocarbon tails in DPPC, increasing the DPPC content of the mixed membrane increases its stability against the disinfectant. At high DPPC concentrations, where the DOPC and DMPC molecules are confined between the DPPC lipids, the ordered hydrocarbon tails of DPPC also induce order in the DOPC and DMPC molecules and, hence, stabilize the membrane more. Our simulations on pure and mixed membranes of a diversity of compositions reveal that a maximum ethanol concentration of 32 mol % (55 wt %) in the alcohol-based disinfectants is enough to disintegrate any membrane composed of these three lipids.
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Affiliation(s)
- Tianhang Zhou
- Eduard-Zintl-Institut für Anorganische und
Physikalische Chemie, Technische Universität Darmstadt,
Alarich-Weiss-Strasse 8, 64287 Darmstadt, Germany
| | - Zhenghao Wu
- Eduard-Zintl-Institut für Anorganische und
Physikalische Chemie, Technische Universität Darmstadt,
Alarich-Weiss-Strasse 8, 64287 Darmstadt, Germany
| | - Shubhadip Das
- Eduard-Zintl-Institut für Anorganische und
Physikalische Chemie, Technische Universität Darmstadt,
Alarich-Weiss-Strasse 8, 64287 Darmstadt, Germany
| | - Hossein Eslami
- Eduard-Zintl-Institut für Anorganische und
Physikalische Chemie, Technische Universität Darmstadt,
Alarich-Weiss-Strasse 8, 64287 Darmstadt, Germany
- College of Sciences, Persian Gulf
University, Boushehr 75168, Iran
| | - Florian Müller-Plathe
- Eduard-Zintl-Institut für Anorganische und
Physikalische Chemie, Technische Universität Darmstadt,
Alarich-Weiss-Strasse 8, 64287 Darmstadt, Germany
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17
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Li P, Kang N, Chai A, Lu D, Luo S, Yang Z. Vesicle Geometries Enabled by Semiflexible Polymer. Polymers (Basel) 2022; 14:polym14040757. [PMID: 35215670 PMCID: PMC8875028 DOI: 10.3390/polym14040757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 02/10/2022] [Accepted: 02/12/2022] [Indexed: 12/02/2022] Open
Abstract
Understanding and controlling vesicle shapes is fundamental challenge in biophysics and materials design. In this paper, we employ the Monte Carlo method to investigate the shape of soft vesicle induced by semiflexible polymer outside in two dimensions. The effect of bending stiffness κ of polymer and the strength εVP of attractive interaction between vesicle and polymer on the shape of vesicle is discussed in detail in the present paper. It is found that the shape of vesicle is influenced by κ and εVP. Typical shape of vesicles is observed, such as circular, cigar-like, double vesicle, and racquet-like. To engineer vesicle shape transformations is helpful for exploiting the richness of vesicle geometries for desired applications.
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Affiliation(s)
- Ping Li
- Department of Physics, Jiangxi Agricultural University, Nanchang 330045, China; (P.L.); (N.K.); (D.L.); (S.L.)
| | - Nianqiang Kang
- Department of Physics, Jiangxi Agricultural University, Nanchang 330045, China; (P.L.); (N.K.); (D.L.); (S.L.)
| | - Aihua Chai
- College of Data Science, Jiaxing University, Jiaxing 314001, China;
| | - Dan Lu
- Department of Physics, Jiangxi Agricultural University, Nanchang 330045, China; (P.L.); (N.K.); (D.L.); (S.L.)
| | - Shuiping Luo
- Department of Physics, Jiangxi Agricultural University, Nanchang 330045, China; (P.L.); (N.K.); (D.L.); (S.L.)
| | - Zhiyong Yang
- Department of Physics, Jiangxi Agricultural University, Nanchang 330045, China; (P.L.); (N.K.); (D.L.); (S.L.)
- Correspondence: ; Tel.: +86-152-7002-1582
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18
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Bahri K, Eslami H, Müller-Plathe F. Self-Assembly of Model Triblock Janus Colloidal Particles in Two Dimensions. J Chem Theory Comput 2022; 18:1870-1882. [PMID: 35157474 DOI: 10.1021/acs.jctc.1c01116] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A simplified two-dimensional effective-solvent model of triblock Janus particles, consisting of three interaction sites in a linear configuration, a core particle, and two particles modeling the attractive patches at the poles, is developed to study the mechanism of nucleation and self-assembly in triblock Janus particles. The potential energy parameters are tuned against phase transition temperatures and free energy barriers to the nucleation of crystalline phases, calculated from our previous detailed model of Janus particles. Vapor-liquid equilibria and critical temperatures are calculated by grand-canonical molecular dynamics simulations for particles of different patch widths. With metadynamics, phase equilibria, mechanism of nucleation, and free energy barriers to nucleation are investigated. The minimum free energy path to nucleation indicates two steps. The first step, with a higher free energy increase, consists of the densification of the fluid into a disordered cluster. In the second step, of a lower free energy barrier, the inner particles of the disordered cluster reorient to form a crystalline nucleus. This two-step mechanism of nucleation of a kagome lattice is in complete agreement with the experiment and with our previous simulations using a detailed model of Janus particles. Large systems at a slight supersaturation generate multiple crystalline domains, which are misaligned at the grain boundaries. In complete agreement with the experiment and with previous simulation results, we observe a two-step mechanism for crystal growth: melting of the smaller (less stable) crystallites to a fluid followed by recrystallization at the surface of neighboring bigger (more stable) crystallites. A comparison of the present softer modeling of a Janus particle with harder models in the literature for self-assembly of Janus particles indicates that softer potentials stabilize open lattices (e.g., kagome) more than dense lattices (e.g., hexagonal). Also, experimental locations of phase transition points and barrier heights to nucleation are better reproduced by the present model than by the existing simple models.
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Affiliation(s)
- Kheiri Bahri
- Department of Chemistry, College of Sciences, Persian Gulf University, Boushehr 75168, Iran
| | - Hossein Eslami
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Str. 8, Darmstadt 64287, Germany.,Department of Chemistry, College of Sciences, Persian Gulf University, Boushehr 75168, Iran
| | - Florian Müller-Plathe
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Str. 8, Darmstadt 64287, Germany
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19
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Prasad S, Gupta M. Solvation of gold nanoparticles passivated with functionalized alkylthiols: A molecular dynamics study. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2021.118342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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20
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Study on Effects of Nonlinear Behavior Characteristics of Prepreg Dielectric on Warpage of Substrate under Laminating Process. Polymers (Basel) 2022; 14:polym14030561. [PMID: 35160548 PMCID: PMC8840362 DOI: 10.3390/polym14030561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 01/24/2022] [Accepted: 01/27/2022] [Indexed: 02/01/2023] Open
Abstract
To analyze the effects of nonlinear behavior characteristics of prepreg (PPG) among the insulating materials of substrate and the residual stress of laminating process on the warpage of substrate, this study investigated the continuous laminating process using the numerical analysis by finite element method. The analysis results showed that the warpage of the substrate in the laminating process of PPG was very low, but it increased rapidly in the solder resist (SR) laminating process. As the laminating process of PPG continued, the stress inside the substrate increased continuously and it was predicted to decrease in the SR laminating process. These results confirmed that the warpage of the substrate is influenced the most by the SR laminating process, and that the warpage and stress of substrate accumulated in the laminating process of PPG have significant effects on the final warpage.
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21
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Wu S, Zhao D, Qiu M. 3D Nanoprinting by Electron-Beam with an Ice Resist. ACS APPLIED MATERIALS & INTERFACES 2022; 14:1652-1658. [PMID: 34933558 DOI: 10.1021/acsami.1c18356] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Following the general trend in the miniaturization of electronic devices, techniques that enable 3D printing at the nanometer scale are gaining momentum. As a widely used planar processing method, electron-beam lithography (EBL) can be employed to create 3D nanostructures in a layer-by-layer fashion. However, compared with other 3D printing techniques, EBL is limited by the stringent requirement of a range of fabrication equipment and complex fabrication processes. Here, we have demonstrated that EBL can be developed to a controllable 3D nanoprinting technology with the aid of ice resists. With carefully selected accelerating voltage, electron dose, and ice thickness, 3D objects can be efficiently printed in a single vacuum system through an iterative process of ice deposition and e-beam exposure. Mixed ice resists containing solid anisole and water are also introduced into the printing process, which offer a flexible control of the thickness of printed layers. Apart from carbonaceous objects obtained with our method, 3D printing of metals is also promising by employing organometallic compounds as ice resists. This study provides a fresh perspective in EBL-based nanofabrication and expands the spectrum of modern additive manufacturing.
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Affiliation(s)
- Shan Wu
- College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027, China
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310024, China
- Institute of Advanced Technology, Westlake Institute for Advanced Study, Hangzhou 310024, China
| | - Ding Zhao
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310024, China
- Institute of Advanced Technology, Westlake Institute for Advanced Study, Hangzhou 310024, China
| | - Min Qiu
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310024, China
- Institute of Advanced Technology, Westlake Institute for Advanced Study, Hangzhou 310024, China
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22
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Polymerization and Structure of Opposing Polymer Brushes Studied by Computer Simulations. Polymers (Basel) 2021; 13:polym13244294. [PMID: 34960846 PMCID: PMC8706839 DOI: 10.3390/polym13244294] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 12/03/2021] [Accepted: 12/06/2021] [Indexed: 12/17/2022] Open
Abstract
A model of the polymerization process during the formation of a pair of polymer brushes was designed and investigated. The obtained system consisted of two impenetrable parallel surfaces with the same number of chains grafted on both surfaces. Coarse-grained chains embedded in nodes of a face-centered cubic lattice with excluded volume interactions were obtained by a ‘grafted from’ procedure. The structure of synthesized macromolecular systems was also studied. Monte Carlo simulations using the dynamic lattice liquid model were employed using dedicated parallel machine ARUZ in a large size and time scale. The parameters of the polymerization process were found to be crucial for the proper structure of the brush. It was found that for high grafting densities, chains were increasingly compressed, and there is surprisingly little interpenetration of chains from opposite surfaces. It was predicted and confirmed that in a polydisperse sample, the longer chains have unique configurations consisting of a stretched stem and a coiled crown.
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23
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Syrlybayev D, Zharylkassyn B, Seisekulova A, Perveen A, Talamona D. Optimization of the Warpage of Fused Deposition Modeling Parts Using Finite Element Method. Polymers (Basel) 2021; 13:polym13213849. [PMID: 34771405 PMCID: PMC8587906 DOI: 10.3390/polym13213849] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 11/02/2021] [Accepted: 11/02/2021] [Indexed: 11/16/2022] Open
Abstract
Fused deposition modeling (FDM) is one of the most affordable and widespread additive manufacturing (AM) technologies. Despite its simplistic implementation, the physics behind this FDM process is very complex and involves rapid heating and cooling of the polymer feedstock. As a result, highly non-uniform internal stresses develop within the part, which can cause warpage deformation. The severity of the warpage is highly dependent on the process parameters involved, and therefore, currently extensive experimental studies are ongoing to assess their influence on the final accuracy of the part. In this study, a thermomechanical Finite Element model of the 3D printing process was developed using ANSYS. This model was compared against experimental results and several other analytical models available in the literature. The developed Finite Element Analysis (FEA) model demonstrated a good qualitative and quantitative correlation with the experimental results. An L9 orthogonal array, from Taguchi Design of Experiments, was used for the optimization of the warpage based on experimental results and numerical simulations. The optimum process parameters were identified for each objective and parts were printed using these process parameters. Both parts showed an approximately equal warpage value of 320 μm, which was the lowest among all 10 runs of the L9 array. Additionally, this model is extended to predict the warpage of FDM printed multi-material parts. The relative percentage error between the numerical and experimental warpage results for alternating and sandwich specimens are found to be 1.4% and 9.5%, respectively.
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24
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Shelukhin V. Flows of Linear Polymer Solutions and Other Suspensions of Rod-like Particles: Anisotropic Micropolar-Fluid Theory Approach. Polymers (Basel) 2021; 13:polym13213679. [PMID: 34771236 PMCID: PMC8588494 DOI: 10.3390/polym13213679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/15/2021] [Accepted: 10/16/2021] [Indexed: 12/05/2022] Open
Abstract
We formulate equations governing flows of suspensions of rod-like particles. Such suspensions include linear polymer solutions, FD-virus, and worm-like micelles. To take into account the particles that form and their rotation, we treat the suspension as a Cosserat continuum and apply the theory of micropolar fluids. Anisotropy of suspensions is determined through the inclusion of the microinertia tensor in the rheological constitutive equations. We check that the model is consistent with the basic principles of thermodynamics. In addition to anisotropy, the theory also captures gradient banding instability, coexistence of isotropic and nematic phases, sustained temporal oscillations of macroscopic viscosity, shear thinning and hysteresis. For the flow between two planes, we also establish that the total flow rate depends not only on the pressure gradient, but on the history of its variation as well.
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Affiliation(s)
- Vladimir Shelukhin
- Lavrentyev Institute of Hydrodynamics, 630090 Novosibirsk, Russia;
- Mathematical Department, Novosibirsk State University, 630090 Novosibirsk, Russia
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25
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A High-Similarity Modeling Method for Low-Porosity Porous Material and Its Application in Bearing Cage Self-Lubrication Simulation. MATERIALS 2021; 14:ma14185449. [PMID: 34576673 PMCID: PMC8471339 DOI: 10.3390/ma14185449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 09/17/2021] [Accepted: 09/17/2021] [Indexed: 11/26/2022]
Abstract
The porous oil-containing cage achieves the storage, spillage, and suction of lubricating oil by its micro-pore structure, thus ensuring the self-lubricating performance of the bearing. Carrying out fast and accurate modeling of the cage microscopic pore structure is the key to the analysis of the self-lubricating mechanism of bearings. In response to the issues where current modeling methods of porous materials have a low similarity of pore distribution, morphology, structure, and size characteristics, and the transition of pore surfaces is sharp, this paper proposed a modeling method of a highly similar micro-pore structure based on the idea of median filtering, the quartet structure generation set (QSGS), and the slice method. By extracting and analyzing the pore characteristics of the porous model and comparing them with the experimental results of CT scanning, the advantages of the modeling method in terms of morphology and pore connectivity were verified. Finally, by carrying out simulation analysis of the centrifugal force of oil splashing and capillary oil absorption on the constructed model by combining the parameters of porous structures such as porosity and tortuosity, the advantages of the modeling method in the construction of the porous model and multi-physical field analysis were further verified.
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26
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Zhang HF, Chen XH, Xiao QL, Chen F, Feng Z, Cao S, Zhang J, Qi Y, Shi Z, Ge JY. Evolution of Superconducting Properties in Fe 1.1Se 0.8Te 0.2 Films Before and After Structure Avalanche. ACS APPLIED MATERIALS & INTERFACES 2021; 13:42138-42145. [PMID: 34432434 DOI: 10.1021/acsami.1c10303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
By preparing a series of high-quality Fe1.1Se0.8Te0.2 films on the CaF2 substrate via pulsed laser deposition, we reveal the evolution of the structure as well as the superconductivity with the film thickness. We have found that there exists a threshold thickness above which the critical temperature Tc reaches its optimal value of 23.18 K with large activation energy, promising for high-field technological applications. Most importantly, the thick films have been found in a metastable state due to the fragile balance between the increased strain energy and the large compressive stress. Once the balance is broken by an external perturbation, a unique structure avalanche happens with a large part of the film exfoliated from the substrate and curves out. The exfoliated part of the film remains a single phase, with its lattice parameter and Tc recovering the bulk values. Our results clearly demonstrate the close relation between the compressive stress of the film/substrate interface and the high critical temperature observed in FeSeTe films. Moreover, this also provides an efficient way to fabricate free-standing single-phase FeSeTe crystals in the phase-separation regime.
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Affiliation(s)
- Han-Fang Zhang
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Xing-Hong Chen
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Qi-Ling Xiao
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Fei Chen
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Zhenjie Feng
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Shixun Cao
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
- Department of Physics, Shanghai Key Laboratory for High Temperature Superconductors, Shanghai University, 200444 Shanghai, China
| | - Jincang Zhang
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Yanpeng Qi
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - Zhixiang Shi
- Department of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, 211189 Nanjing, China
| | - Jun-Yi Ge
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
- Department of Physics, Shanghai Key Laboratory for High Temperature Superconductors, Shanghai University, 200444 Shanghai, China
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27
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DPD Study on the Interfacial Properties of PEO/PEO-PPO-PEO/PPO Ternary Blends: Effects of Pluronic Structure and Concentration. Polymers (Basel) 2021; 13:polym13172866. [PMID: 34502907 PMCID: PMC8433662 DOI: 10.3390/polym13172866] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 08/23/2021] [Accepted: 08/25/2021] [Indexed: 12/28/2022] Open
Abstract
Using the method of dissipative particle dynamics (DPD) simulations, we investigated the interfacial properties of PEO/PEO-PPO-PEO/PPO ternary blends composed of the Pluronics L64(EO13PO30EO13), F68(EO76PO29EO76), F88(EO104PO39EO104), or F127(EO106PO70EO106) triblock copolymers. Our simulations show that: (i) The interfacial tensions (γ) of the ternary blends obey the relationship γF68 < γL64 < γF88 < γF127, which indicates that triblock copolymer F68 is most effective in reducing the interfacial tension, compared to L64, F88, and F127; (ii) For the blends of PEO/L64/PPO and the F64 copolymer concentration ranging from ccp = 0.2 to 0.4, the interface exhibits a saturation state, which results in the aggregation and micelle formation of F64 copolymers added to the blends, and a lowered efficiency of the L64 copolymers as a compatibilizer, thus, the interfacial tension decreases slightly; (iii) For the blends of PEO/F68/PPO, elevating the Pluronic copolymer concentration can promote Pluronic copolymer enrichment at the interfaces without forming the micelles, which reduces the interfacial tension significantly. The interfacial properties of the blends contained the PEO-PPO-PEO triblock copolymer compatibilizers are, thus, controlled by the triblock copolymer structure and the concentration. This work provides important insights into the use of the PEO-PPO-PEO triblock copolymer as compatibilizers in the PEO and PPO homopolymer blend systems.
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