1
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Kumar R, Tewari A, Parashar A. Thermal Transport Phenomena in PEGDA-Based Nanocomposite Hydrogels Using Atomistic and Experimental Techniques. J Phys Chem B 2024; 128:5254-5267. [PMID: 38770752 DOI: 10.1021/acs.jpcb.4c01376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Poly(ethylene glycol) diacrylate (PEGDA) hydrogel is a very peculiar, fascinating material with good chemical stability and biocompatibility. However, the poor thermal transport phenomenon in PEGDA, limits its performance in cartilage replacement and developing therapies for treating burns. In this article, a combined experimental and atomistic approach was adopted to investigate the thermal transport phenomena in PEGDA hydrogel with different weight concentrations of boron nitride nanoplatelets as a function of water content. The incorporation of boron nitride nanofillers helps in enhancing the thermal conductivity of PEGDA hydrogels, and the reinforcement effect was more dominating at lower water content. Experimental investigation was complemented with molecular dynamics-based studies to capture the effect of defective (bicrystalline) boron nitride nanosheets on the interfacial thermal conductance in PEGDA hydrogels. It can be concluded from the simulations that defective nanosheets are superior reinforcement for enhancing the thermal transport in PEGDA hydrogels, and this is independent of the water content. These biocompatible boron nitride nanoparticle (BNNP)-incorporated PEGDA hydrogels with enhanced thermal conductivity are promising materials in addressing locally overheating tissues such as cartilage replacement. They may have comprehensive utility for biomedical applications such as tissue engineering, drug delivery, biosensors, and burn therapy.
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2
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Kumari P, Ballone P, Paniagua C, Abou-Saleh RH, Benitez-Alfonso Y. Cellulose-Callose Hydrogels: Computational Exploration of Their Nanostructure and Mechanical Properties. Biomacromolecules 2024; 25:1989-2006. [PMID: 38410888 PMCID: PMC10934845 DOI: 10.1021/acs.biomac.3c01396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 02/06/2024] [Accepted: 02/07/2024] [Indexed: 02/28/2024]
Abstract
Polysaccharides play a crucial role in virtually all living systems. They also represent the biocompatible and fully sustainable component of a variety of nanoparticles, which are of increasing interest in biomedicine, food processing, cosmetics, and structural reinforcement of polymeric materials. The computational modeling of complex polysaccharide phases will assist in understanding the properties and behavior of all these systems. In this paper, structural, bonding, and mechanical properties of 10 wt % cellulose-callose hydrogels (β-glucans coexisting in plant cell walls) were investigated by atomistic simulations. Systems of this kind have recently been introduced in experiments revealing unexpected interactions between the polysaccharides. Starting from initial configurations inspired by X-ray diffraction data, atomistic models made of ∼1.6 × 106 atoms provide a qualitatively consistent view of these hydrogels, displaying stability, homogeneity, connectivity, and elastic properties beyond those of a liquid suspension. The simulation shows that the relatively homogeneous distribution of saccharide nanofibers and chains in water is not due to the solubility of cellulose and callose, but to the formation of a number of cross-links among the various sample components. The broad distribution of strength and elasticity among the links implies a degree of anharmonicity and irreversible deformation already evident at low external load. Besides the qualitative agreement with experimental observations, the simulation results display also quantitative disagreements in the estimation of elastic coefficients, such as the Young's modulus, that require further investigation. Complementary simulations of dense cellulose-callose mixtures (no hydrogels) highlight the role of callose in smoothing the contact surface of different nanofibers forming larger bundles. Cellulose-callose structures in these systems displayed an enhanced water uptake and delayed dye release when compared to cellulose alone, highlighting potential new applications as drug delivery scaffolds. The simulation trajectories provide a tuning and testing ground for the development of coarse-grained models that are required for the large scale investigation of mechanical properties of cellulose and callose mixtures in a watery environment.
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Affiliation(s)
- Pallavi Kumari
- The
Astbury Centre and the Centre for Plant Science, School of Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom
- School
of Physics and Astronomy, University of
Leeds, Woodhouse Lane, Leeds, LS2 9JT, United Kingdom
| | - Pietro Ballone
- School
of Physics, University College Dublin, Dublin 4 D04 C1P1, Ireland
- Conway
Institute for Biomolecular and Biomedical Research, University College Dublin, Dublin
4 D04 C1P1, Ireland
| | - Candelas Paniagua
- The
Astbury Centre and the Centre for Plant Science, School of Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom
- Instituto
de Hortofruticultura Subtropical y Mediterránea (IHSM-UMA-CSIC).
Dpto. Botánica y Fisiología Vegetal, Universidad de Málaga, 29071, Málaga, Spain
| | - Radwa H. Abou-Saleh
- School
of Physics and Astronomy, University of
Leeds, Woodhouse Lane, Leeds, LS2 9JT, United Kingdom
- Department
of Physics, Faculty of Science, Galala University, Galala Plateau, Attaka, Suez 43511, Egypt
- Department
of Physics, Faculty of Science, Mansoura
University, El Gomhouria
St, El Mansoura 1, Dakahlia Governorate 35516, Egypt
| | - Yoselin Benitez-Alfonso
- The
Astbury Centre and the Centre for Plant Science, School of Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom
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3
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Kumar R, Parashar A. Effect of the degree of polymerization and water content on the thermal transport phenomena in PEGDA hydrogel: a molecular-dynamics-based study. Phys Chem Chem Phys 2023. [PMID: 37409672 DOI: 10.1039/d3cp00667k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/07/2023]
Abstract
A hydrogel is a 3D cross-linked polymer network that can absorb copious amounts of water or biological fluid. Due to their biocompatibility and non-toxicity, hydrogels have a wide range of applications in biomedical engineering. To develop hydrogels with superior thermal dissipation properties, atomistic-level studies are required to quantify the effect of the water content and the degree of polymerization. Classical mechanics-based non-equilibrium molecular dynamics (NEMD) simulations were performed in conjunction with a mathematical formulation developed by Müller-Plathe to explore the thermal conductivity of the poly(ethylene glycol)diacrylate (PEGDA) hydrogel. This work reveals that the thermal conductivity of the PEGDA hydrogel is enhanced with the increase in water content and approaches the value of the thermal conductivity of water at 85% water content in the hydrogel. The PEGDA-9 hydrogel, with a lower level of degree of polymerization, has a superior thermal conductivity than the PEGDA-13 and PEGDA-23 hydrogels. The lower level of degree of polymerization is associated with the higher mesh density of polymer chain network junctions that help to achieve the superior thermal conductivity at higher water contents. Increasing the water content improves the structural stability and compactness of the polymer chains, which can be further associated with the enhanced phonon transfer in PEGDA hydrogels. The work will help in the development of PEGDA-based hydrogels with superior thermal dissipation properties for tissue engineering.
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Affiliation(s)
- Raju Kumar
- Department of Mechanical and Industrial Engineering Indian Institute of Technology, Roorkee 247667, Uttarakhand, India.
| | - Avinash Parashar
- Department of Mechanical and Industrial Engineering Indian Institute of Technology, Roorkee 247667, Uttarakhand, India.
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4
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Chi C, Liu G, An M, Zhang Y, Song D, Qi X, Zhao C, Wang Z, Du Y, Lin Z, Lu Y, Huang H, Li Y, Lin C, Ma W, Huang B, Du X, Zhang X. Reversible bipolar thermopower of ionic thermoelectric polymer composite for cyclic energy generation. Nat Commun 2023; 14:306. [PMID: 36658195 PMCID: PMC9852232 DOI: 10.1038/s41467-023-36018-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 01/11/2023] [Indexed: 01/21/2023] Open
Abstract
The giant thermopower of ionic thermoelectric materials has attracted great attention for waste-heat recovery technologies. However, generating cyclic power by ionic thermoelectric modules remains challenging, since the ions cannot travel across the electrode interface. Here, we reported a reversible bipolar thermopower (+20.2 mV K-1 to -10.2 mV K-1) of the same composite by manipulating the interactions of ions and electrodes. Meanwhile, a promising ionic thermoelectric generator was proposed to achieve cyclic power generation under a constant heat course only by switching the external electrodes that can effectively realize the alternating dominated thermodiffusion of cations and anions. It eliminates the necessity to change the thermal contact between material and heat, nor does it require re-establish the temperature differences, which can favor improving the efficiency of the ionic thermoelectrics. Furthermore, the developed micro-thermal sensors demonstrated high sensitivity and responsivity in light detecting, presenting innovative impacts on exploring next-generation ionic thermoelectric devices.
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Affiliation(s)
- Cheng Chi
- grid.12527.330000 0001 0662 3178Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, 100084 Beijing, China ,grid.261049.80000 0004 0645 4572Key Laboratory of Power Station Energy Transfer Conversion and System of Ministry of Education, School of Energy Power and Mechanical Engineering, North China Electric Power University, 102206 Beijing, China
| | - Gongze Liu
- grid.24515.370000 0004 1937 1450Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong SAR, China
| | - Meng An
- grid.12527.330000 0001 0662 3178Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, 100084 Beijing, China ,grid.454711.20000 0001 1942 5509College of Mechanical and Electrical Engineering, Shaanxi University of Science and Technology, 710021 Xi’an, China
| | - Yufeng Zhang
- grid.12527.330000 0001 0662 3178Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, 100084 Beijing, China
| | - Dongxing Song
- grid.12527.330000 0001 0662 3178Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, 100084 Beijing, China
| | - Xin Qi
- grid.12527.330000 0001 0662 3178Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, 100084 Beijing, China
| | - Chunyu Zhao
- grid.12527.330000 0001 0662 3178Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, 100084 Beijing, China
| | - Zequn Wang
- grid.454711.20000 0001 1942 5509College of Mechanical and Electrical Engineering, Shaanxi University of Science and Technology, 710021 Xi’an, China
| | - Yanzheng Du
- grid.12527.330000 0001 0662 3178Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, 100084 Beijing, China
| | - Zizhen Lin
- grid.12527.330000 0001 0662 3178Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, 100084 Beijing, China
| | - Yang Lu
- grid.12527.330000 0001 0662 3178Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, 100084 Beijing, China
| | - He Huang
- grid.24515.370000 0004 1937 1450Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong SAR, China
| | - Yang Li
- grid.24515.370000 0004 1937 1450Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong SAR, China
| | - Chongjia Lin
- grid.24515.370000 0004 1937 1450Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong SAR, China
| | - Weigang Ma
- grid.12527.330000 0001 0662 3178Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, 100084 Beijing, China
| | - Baoling Huang
- grid.24515.370000 0004 1937 1450Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong SAR, China
| | - Xiaoze Du
- grid.261049.80000 0004 0645 4572Key Laboratory of Power Station Energy Transfer Conversion and System of Ministry of Education, School of Energy Power and Mechanical Engineering, North China Electric Power University, 102206 Beijing, China
| | - Xing Zhang
- grid.12527.330000 0001 0662 3178Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, 100084 Beijing, China
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5
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Kumar R, Parashar A. Atomistic simulations of pristine and nanoparticle reinforced hydrogels: A review. WIRES COMPUTATIONAL MOLECULAR SCIENCE 2023. [DOI: 10.1002/wcms.1655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Raju Kumar
- Department of Mechanical and Industrial Engineering Indian Institute of Technology Roorkee Uttarakhand India
| | - Avinash Parashar
- Department of Mechanical and Industrial Engineering Indian Institute of Technology Roorkee Uttarakhand India
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6
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Mercado-Montijo J, Anstine DM, Rukmani SJ, Colina CM, Andrew JS. PEGDA hydrogel structure from semi-dilute concentrations: insights from experiments and molecular simulations. SOFT MATTER 2022; 18:3565-3574. [PMID: 35466967 DOI: 10.1039/d1sm01708j] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The efficacy of hydrogel materials used in biomedical applications is dependent on polymer network topology and the structure of water-laden pore space. Hydrogel microstructure can be tuned by adjusting synthesis parameters such as macromer molar mass and concentration. Moreover, hydrogels beyond dilute conditions are needed to produce mechanically robust and dense networks for tissue engineering and/or drug delivery systems. Thus, this study utilizes a combined experimental and molecular simulation approach to characterize structural features for 4.8 and 10 kDa poly (ethylene glycol) diacrylate (PEGDA) hydrogels formed from a range of semi-dilute solution concentrations. The connection between chain-chain interactions in polymer solutions, hydrogel structure, and equilibrium swelling behavior is presented. Bulk rheology analysis revealed an entanglement concentration for PEGDA pre-gel solutions around 28 wt% for both macromers studied. A similar transition in swelling behavior was revealed around the same concentration where hydrogel capacity to retain water was drastically reduced. To understand this transition, the hydrogel structure was characterized using the swollen polymer network hypothesis and compared to pore size distributions from molecular dynamics simulations. We find in both approaches a structural transition concentration at the hydrogel swelling inflection point that is comparable to the entanglement concentration. Calculated mesh sizes from theory are compared with computationally determined average maximum pore diameters; mesh sizes from theory yielded greater feature sizes across all concentrations considered. Molecular simulations are further used to assess pore dynamics, which are shown to vary in distribution shape and number of modes compared to the time-averaged hydrogel pore features. Altogether, this work provides insights into hydrogel network features and their dynamic behavior at physiological conditions (37 °C) as a basis for hydrogel design beyond dilute conditions for biomedical applications.
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Affiliation(s)
- Jomary Mercado-Montijo
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611, USA.
| | - Dylan M Anstine
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611, USA.
- George and Josephine Butler Polymer Research Laboratory, University of Florida, Gainesville, Florida 32611, USA
| | - Shalini J Rukmani
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611, USA.
- George and Josephine Butler Polymer Research Laboratory, University of Florida, Gainesville, Florida 32611, USA
| | - Coray M Colina
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611, USA.
- George and Josephine Butler Polymer Research Laboratory, University of Florida, Gainesville, Florida 32611, USA
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, USA
| | - Jennifer S Andrew
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611, USA.
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7
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Chi C, An M, Qi X, Li Y, Zhang R, Liu G, Lin C, Huang H, Dang H, Demir B, Wang Y, Ma W, Huang B, Zhang X. Selectively tuning ionic thermopower in all-solid-state flexible polymer composites for thermal sensing. Nat Commun 2022; 13:221. [PMID: 35017492 PMCID: PMC8752756 DOI: 10.1038/s41467-021-27885-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 12/17/2021] [Indexed: 12/26/2022] Open
Abstract
There has been increasing interest in the emerging ionic thermoelectric materials with huge ionic thermopower. However, it's challenging to selectively tune the thermopower of all-solid-state polymer materials because the transportation of ions in all-solid-state polymers is much more complex than those of liquid-dominated gels. Herein, this work provides all-solid-state polymer materials with a wide tunable thermopower range (+20~-6 mV K-1), which is different from previously reported gels. Moreover, the mechanism of p-n conversion in all-solid-state ionic thermoelectric polymer material at the atomic scale was presented based on the analysis of Eastman entropy changes by molecular dynamics simulation, which provides a general strategy for tuning ionic thermopower and is beneficial to understand the fundamental mechanism of the p-n conversion. Furthermore, a self-powered ionic thermoelectric thermal sensor fabricated by the developed p- and n-type polymers demonstrated high sensitivity and durability, extending the application of ionic thermoelectric materials.
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Affiliation(s)
- Cheng Chi
- Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China
| | - Meng An
- Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China
- College of Mechanical & Electrical Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, China
| | - Xin Qi
- Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China
| | - Yang Li
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong SAR, China
| | - Ruihan Zhang
- Department of Mechanical Engineering, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA, 01609, USA
| | - Gongze Liu
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong SAR, China
| | - Chongjia Lin
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong SAR, China
| | - He Huang
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong SAR, China
| | - Hao Dang
- Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China
| | - Baris Demir
- Centre for Theoretical and Computational Molecular Science, The Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Yan Wang
- Department of Mechanical Engineering, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA, 01609, USA
| | - Weigang Ma
- Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China.
| | - Baoling Huang
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong SAR, China.
| | - Xing Zhang
- Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China
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8
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Shi L, Ren L, Li Y, Fu X, Meng S, Wang J. A study of the mechanical properties of the NEPE binders by molecular dynamic simulations and experiments. RSC Adv 2022; 12:16319-16328. [PMID: 35733693 PMCID: PMC9157741 DOI: 10.1039/d2ra02692a] [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: 04/28/2022] [Accepted: 05/16/2022] [Indexed: 11/21/2022] Open
Abstract
In this study, the crosslinking structures of nitrate ester plasticized polyether (NEPE) binders were constructed by a computational procedure. Based on the final crosslinking models, the glass transition temperatures, mechanical properties, and thermal expansion coefficients of polyethylene glycol400/multi-functional isocyanate (PEG400/N-100), polyethylene glycol400/toluene diisocyanate (PEG400/HDI), polyethylene glycol400/hexamethylene diisocyanate (PEG400/TDI) and polyethylene glycol400/isophorone diisocyanate (PEG400/IPDI) models were simulated by molecular dynamics, and could be confirmed by experiments. Then the bond-length distributions, conformation properties and cohesive energy densities were used to analyze in detail how the different cured structures influenced the mechanical and thermal properties. Furthermore, the radial distribution function, mean square radius of gyration, volume shrinkage and fraction free volume were calculated, which could directly explain the relationships between the intermolecular chains and macroscopical properties of the NEPE binders. Lastly, PEG400/N-100 and PEG400/HDI systems were chosen for the experiments. The dynamic mechanical analysis results explained that PEG400-HDI showed better flexibility and its Tg value was 45 °C lower than that of PEG400-N100. The mechanical properties illustrated that the ultimate tensile strength and Young's modulus of PEG400/N-100 were both to an extent higher than that of PEG400/HDI in the temperature range of −40 °C to 50 °C, according to the results provided by a universal tensile test machine. The experimental results were in good agreement with the simulation analysis. This work can help us to have an efficient comprehension on the crosslinking structures and micro-property relationships of the NEPE binders and act as a guidance for designing applicable polyurethanes in propellant applications. The mechanical properties of NEPE binders were performed well with combining simulations and experiments.![]()
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Affiliation(s)
- La Shi
- Xi'an Modern Chemistry Research Institute, Xi'an 710065, China
| | - Li Ren
- Xi'an Modern Chemistry Research Institute, Xi'an 710065, China
| | - Yang Li
- Xi'an Modern Chemistry Research Institute, Xi'an 710065, China
| | - Xiaolong Fu
- Xi'an Modern Chemistry Research Institute, Xi'an 710065, China
| | - Saiqin Meng
- Xi'an Modern Chemistry Research Institute, Xi'an 710065, China
| | - Jiangning Wang
- Xi'an Modern Chemistry Research Institute, Xi'an 710065, China
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9
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Demir B, Chan KY, Searles DJ. Structural Electrolytes Based on Epoxy Resins and Ionic Liquids: A Molecular-Level Investigation. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c00824] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Baris Demir
- Centre for Theoretical and Computational Molecular Science, The Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Kit-ying Chan
- Centre for Translational Atomaterials, Swinburne University of Technology, Hawtorn, Melbourne, VIC 3122, Australia
| | - Debra J. Searles
- Centre for Theoretical and Computational Molecular Science, The Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
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10
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Gavriil V, Chatzichristidi M, Christofilos D, Kourouklis GA, Kollia Z, Bakalis E, Cefalas AC, Sarantopoulou E. Entropy and Random Walk Trails Water Confinement and Non-Thermal Equilibrium in Photon-Induced Nanocavities. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E1101. [PMID: 32498312 PMCID: PMC7353189 DOI: 10.3390/nano10061101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/18/2020] [Accepted: 05/22/2020] [Indexed: 01/18/2023]
Abstract
Molecules near surfaces are regularly trapped in small cavitations. Molecular confinement, especially water confinement, shows intriguing and unexpected behavior including surface entropy adjustment; nevertheless, observations of entropic variation during molecular confinement are scarce. An experimental assessment of the correlation between surface strain and entropy during molecular confinement in tiny crevices is difficult because strain variances fall in the nanometer scale. In this work, entropic variations during water confinement in 2D nano/micro cavitations were observed. Experimental results and random walk simulations of water molecules inside different size nanocavitations show that the mean escaping time of molecular water from nanocavities largely deviates from the mean collision time of water molecules near surfaces, crafted by 157 nm vacuum ultraviolet laser light on polyacrylamide matrixes. The mean escape time distribution of a few molecules indicates a non-thermal equilibrium state inside the cavity. The time differentiation inside and outside nanocavities reveals an additional state of ordered arrangements between nanocavities and molecular water ensembles of fixed molecular length near the surface. The configured number of microstates correctly counts for the experimental surface entropy deviation during molecular water confinement. The methodology has the potential to identify confined water molecules in nanocavities with life science importance.
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Affiliation(s)
- Vassilios Gavriil
- National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vassileos Constantinou Avenue, 11635 Athens, Greece; (V.G.); (Z.K.); (E.B.); (A.-C.C.)
- School of Chemical Engineering and Physics Laboratory, Faculty of Engineering, Aristotle University of Thessaloniki, University Campus, 54124 Thessaloniki, Greece; (D.C.); (G.A.K.)
| | - Margarita Chatzichristidi
- Department of Chemistry, Laboratory of Industrial Chemistry, Panepistimiopolis Zografou, National and Kapodistrian University of Athens, 15771 Athens, Greece;
| | - Dimitrios Christofilos
- School of Chemical Engineering and Physics Laboratory, Faculty of Engineering, Aristotle University of Thessaloniki, University Campus, 54124 Thessaloniki, Greece; (D.C.); (G.A.K.)
| | - Gerasimos A. Kourouklis
- School of Chemical Engineering and Physics Laboratory, Faculty of Engineering, Aristotle University of Thessaloniki, University Campus, 54124 Thessaloniki, Greece; (D.C.); (G.A.K.)
| | - Zoe Kollia
- National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vassileos Constantinou Avenue, 11635 Athens, Greece; (V.G.); (Z.K.); (E.B.); (A.-C.C.)
| | - Evangelos Bakalis
- National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vassileos Constantinou Avenue, 11635 Athens, Greece; (V.G.); (Z.K.); (E.B.); (A.-C.C.)
- Dipartimento di Chimica “G. Giamician” University di Bologna, Via F. Selmi 2, 40126 Bologna, Italy
| | - Alkiviadis-Constantinos Cefalas
- National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vassileos Constantinou Avenue, 11635 Athens, Greece; (V.G.); (Z.K.); (E.B.); (A.-C.C.)
| | - Evangelia Sarantopoulou
- National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vassileos Constantinou Avenue, 11635 Athens, Greece; (V.G.); (Z.K.); (E.B.); (A.-C.C.)
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11
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Enhancing the Thermo-Mechanical Property of Polymer by Weaving and Mixing High Length-Diameter Ratio Filler. Polymers (Basel) 2020; 12:polym12061255. [PMID: 32486186 PMCID: PMC7361691 DOI: 10.3390/polym12061255] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 02/06/2020] [Accepted: 02/10/2020] [Indexed: 01/28/2023] Open
Abstract
Improving thermo-mechanical characteristics of polymers can efficiently promote their applications in heat exchangers and thermal management. However, a feasible way to enhance the thermo-mechanical property of bulk polymers at low filler content still remains to be explored. Here, we propose mixing high length-diameter ratio filler such as carbon nanotube (CNT), boron nitride (BN) nanotube, and copper (Cu) nanowire, in the woven polymer matrix to meet the purpose. Through molecular dynamics (MD) simulation, the thermal properties of three woven polymers including woven polyethylene (PE), woven poly (p-phenylene) (PPP), and woven polyacetylene (PA) are investigated. Besides, using woven PE as a polymer matrix, three polymer nanocomposites, namely PE-CNT, PE-BN, and PE-Cu, are constructed by mixing CNT, BN nanotube, and Cu nanowire respectively, whose thermo-mechanical characteristics are compared via MD simulation. Morphology and phonons spectra analysis are conducted to reveal the underlying mechanisms. Furthermore, impacts of electron-phonon coupling and electrical field on the thermal conductivity of PE-Cu are uncovered via two temperature model MD simulation. Classical theoretical models are modified to predict the effects of filler and matrix on the thermal conductivity of polymer nanocomposites. This work can provide useful guidelines for designing thermally conductive bulk polymers and polymer nanocomposites.
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Lei J, Xu S, Li Z, Liu Z. Study on Large Deformation Behavior of Polyacrylamide Hydrogel Using Dissipative Particle Dynamics. Front Chem 2020; 8:115. [PMID: 32158745 PMCID: PMC7052281 DOI: 10.3389/fchem.2020.00115] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 02/07/2020] [Indexed: 12/17/2022] Open
Abstract
Meso-scale models for hydrogels are crucial to bridge the conformation change of polymer chains in micro-scale to the bulk deformation of hydrogel in macro-scale. In this study, we construct coarse-grain bead-spring models for polyacrylamide (PAAm) hydrogel and investigate the large deformation and fracture behavior by using Dissipative Particle Dynamics (DPD) to simulate the crosslinking process. The crosslinking simulations show that sufficiently large diffusion length of polymer beads is necessary for the formation of effective polymer. The constructed models show the reproducible realistic structure of PAAm hydrogel network, predict the reasonable crosslinking limit of water content and prove to be sufficiently large for statistical averaging. Incompressible uniaxial tension tests are performed in three different loading rates. From the nominal stress-stretch curves, it demonstrated that both the hyperelasticity and the viscoelasticity in our PAAm hydrogel models are reflected. The scattered large deformation behaviors of three PAAm hydrogel models with the same water content indicate that the mesoscale conformation of polymer network dominates the mechanical behavior in large stretch. This is because the effective chains with different initial length ratio stretch to straight at different time. We further propose a stretch criterion to measure the fracture stretch of PAAm hydrogel using the fracture stretch of C-C bonds. Using the stretch criterion, specific upper and lower limits of the fracture stretch are given for each PAAm hydrogel model. These ranges of fracture stretch agree quite well with experimental results. The study shows that our coarse-grain PAAm hydrogel models can be applied to numerous single network hydrogel systems.
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Affiliation(s)
- Jincheng Lei
- International Center for Applied Mechanics, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Jiaotong University, Xi'an, China
| | - Shuai Xu
- International Center for Applied Mechanics, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Jiaotong University, Xi'an, China
| | - Ziqian Li
- International Center for Applied Mechanics, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Jiaotong University, Xi'an, China
| | - Zishun Liu
- International Center for Applied Mechanics, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Jiaotong University, Xi'an, China
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Rukmani SJ, Anstine DM, Munasinghe A, Colina CM. An Insight into Structural and Mechanical Properties of Ideal‐Networked Poly(Ethylene Glycol)–Peptide Hydrogels from Molecular Dynamics Simulations. MACROMOL CHEM PHYS 2020. [DOI: 10.1002/macp.201900326] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Shalini J. Rukmani
- Department of Materials Science and EngineeringUniversity of Florida Gainesville FL 32611 USA
- George and Josephine Butler Polymer Research LaboratoryDepartment of ChemistryUniversity of Florida Gainesville FL 32611 USA
| | - Dylan M. Anstine
- Department of Materials Science and EngineeringUniversity of Florida Gainesville FL 32611 USA
- George and Josephine Butler Polymer Research LaboratoryDepartment of ChemistryUniversity of Florida Gainesville FL 32611 USA
| | - Aravinda Munasinghe
- George and Josephine Butler Polymer Research LaboratoryDepartment of ChemistryUniversity of Florida Gainesville FL 32611 USA
- Department of ChemistryUniversity of Florida Gainesville FL 32611 USA
| | - Coray M. Colina
- Department of Materials Science and EngineeringUniversity of Florida Gainesville FL 32611 USA
- George and Josephine Butler Polymer Research LaboratoryDepartment of ChemistryUniversity of Florida Gainesville FL 32611 USA
- Department of ChemistryUniversity of Florida Gainesville FL 32611 USA
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Rukmani SJ, Lin P, Andrew JS, Colina CM. Molecular Modeling of Complex Cross-Linked Networks of PEGDA Nanogels. J Phys Chem B 2019; 123:4129-4138. [PMID: 31038311 DOI: 10.1021/acs.jpcb.9b01622] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Poly(ethylene glycol) (PEG)-based nanogels are attractive for biomedical applications due to their biocompatibility, versatile end group chemistry, and ability to sterically shield encapsulated drug molecules. The characteristics of a hydrogel network govern the encapsulation and efficient delivery of drug molecules for a target application. A molecular-level description of network topology can complement experimental investigations to understand its effects on the structural properties of these nanogels. In this work, atomistic molecular simulations of heterogeneous, nonideal PEG-diacrylate (PEGDA) nanogels are presented. The effects of cross-linking density and topological features on the structural properties of PEGDA nanogels were studied. The average functionality was controlled to systematically study the effect of cross-linking density on the radius of gyration, shape, and mesh size of the nanogels. For a given average functionality, the impact of distinct network topologies on the structural properties was also studied. The aspect ratios, based on the gyration tensor, were calculated to characterize the shapes of these nanogels for different topologies. Nanogel structures with higher cross-linking densities showed a globular shape, while structures with lower cross-linking density showed shape anisotropy. The distribution and connectivity of the cross-linked junctions played a key role in determining the size and shape anisotropy of PEGDA nanogels; the number of unreacted chain ends and their connectivity directly affected the anisotropy. The mesh size, denoted by the limiting "free volume element" present in the nanogel samples, does not show a significant change with increasing average functionality. This work provides insight into the structural properties of heterogeneous hydrogels that aid the design of nonideal nanogel networks for a targeted drug delivery application.
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Surblys D, Matsubara H, Kikugawa G, Ohara T. Application of atomic stress to compute heat flux via molecular dynamics for systems with many-body interactions. Phys Rev E 2019; 99:051301. [PMID: 31212446 DOI: 10.1103/physreve.99.051301] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Indexed: 06/09/2023]
Abstract
Although the computation of heat flux and thermal conductivity either via Fourier's law or the Green-Kubo relation has become a common task in molecular dynamics simulation, contributions of three-body and larger many-body interactions have always proved problematic to compute. In recent years, due to the success when applying to pressure tensor computation, atomic stress approximation has been widely used to calculate heat flux, where the lammps molecular dynamics package is the most prominent propagator. We demonstrated that the atomic stress approximation, while adequate for obtaining pressure, produces erroneous results in the case of heat flux when applied to systems with many-body interactions, such as angle, torsion, or improper potentials. This also produces incorrect thermal conductivity values. To remedy this deficiency, by starting from a strict formulation of heat flux with many-body interactions, we reworked the atomic stress definition which resulted in only a simple modification. We modified the lammps package accordingly to demonstrate that the new atomic stress approximation produces excellent results close to that of a rigid formulation.
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Affiliation(s)
- Donatas Surblys
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Hiroki Matsubara
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Gota Kikugawa
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Taku Ohara
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
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Tahini HA, Tan X, Smith SC. Computational Materials Science: Discovering and Accelerating Future Technologies. ADVANCED THEORY AND SIMULATIONS 2019. [DOI: 10.1002/adts.201900023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Hassan A. Tahini
- Integrated Materials Design Laboratory; Research School of Physics and Engineering; Australian National University; Canberra ACT 2601 Australia
| | - Xin Tan
- Integrated Materials Design Laboratory; Research School of Physics and Engineering; Australian National University; Canberra ACT 2601 Australia
| | - Sean C. Smith
- Integrated Materials Design Laboratory; Research School of Physics and Engineering; Australian National University; Canberra ACT 2601 Australia
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