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Zheng X, Xu L, Douglas JF, Xia W. Role of additive size in the segmental dynamics and mechanical properties of cross-linked polymers. NANOSCALE 2024. [PMID: 39189325 DOI: 10.1039/d4nr02631d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/28/2024]
Abstract
Thermoset materials often involve the addition of molecular and nanoparticle additives to alter various chemo-physical properties of importance in their ultimate applications. The resulting compositional heterogeneities can lead to either enhancement or degradation of thermoset properties, depending on the additive chemical structure and concentration. We tentatively explore this complex physical phenomenon through the consideration of a model polymeric additive to our coarse-grained (CG) thermoset investigated in previous works by simply varying the size of additive segments compared to those of polymer melt. We find that the additive modified thermoset material becomes chemically heterogeneous from additive aggregation when the additive segments become much smaller than those of the thermoset molecules, and a clear evidence is observed in the spatial distribution of local molecular stiffness estimated from Debye-Waller factor 〈u2〉. Despite the non-monotonic variation trends observed in dynamical and mechanical properties with decreasing additive segmental size, both the structural relaxation time and moduli (i.e., shear modulus and bulk modulus) exhibit scaling laws with 〈u2〉. The present work highlights the complex role of additive size played in the dynamical and mechanical properties of thermoset polymers, which should provide a better understanding for the glass formation process of cross-linked polymer composites.
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Affiliation(s)
- Xiangrui Zheng
- Department of Mechanics, School of Aerospace Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Lan Xu
- Department of Aerospace Engineering, Iowa State University, Ames, Iowa 50011, USA.
| | - Jack F Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
| | - Wenjie Xia
- Department of Aerospace Engineering, Iowa State University, Ames, Iowa 50011, USA.
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Gupta SK, Deshpande AP, Kumar R. Rheological and dielectric behavior of sodium carboxymethyl cellulose (NaCMC)/Ca 2+ and esterified NaCMC/Ca 2+ hydrogels: Correlating microstructure and dynamics with properties. Carbohydr Polym 2024; 335:122049. [PMID: 38616088 DOI: 10.1016/j.carbpol.2024.122049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 02/29/2024] [Accepted: 03/12/2024] [Indexed: 04/16/2024]
Abstract
Polyelectrolyte-based conductive hydrogels are being extensively explored for applications in energy storage and as electrode materials for batteries. We synthesized ionically crosslinked sodium carboxymethyl cellulose (NaCMC), esterified NaCMC, and Ca2+ doped esterified NaCMC hydrogels. This work aims to understand the effect of Ca2+ ions on the NaCMC and esterified NaCMC. FTIR, SEM, Rheology and EIS studies were performed to understand the structure and dynamics of hydrogels. Results confirmed that Ca2+ ions have an important role in determining the rheological and dielectric response of hydrogels. Power law behavior was observed in their rheological response with exponent (n) of 0.81 for G' and 0.76 for G″ of ionically crosslinked NaCMC, 5.38 for G' and 4.70 for G″ of esterified NaCMC, whereas, negative exponents -1.44 for G' and -1.10 for G″ of Ca2+ ion doped esterified NaCMC. Ionically crosslinked NaCMC hydrogels have relaxation times (τ) in the range of 8.9 × 10-5 s-2.8 × 10-5 s may be due to the formation of temporary dipoles by electrostatic bridge formations with dc conductivity of (0.1 S/cm-5 S/cm), whereas, esterified NaCMC showed relaxation times (10-3 s-8.9 × 10-5 s) with increasing ester crosslinks and dc conductivity of (0.05 S/cm-0.8 S/cm). Interestingly, Ca2+ ion doped esterified hydrogels showed multiple dielectric relaxations on Ca2+ ion addition with different relaxation times may be due to change in ionic environment. The understanding obtained from this work may be useful for designing tuneable hydrogels with optimum electrical and mechanical properties.
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Affiliation(s)
- Sateesh Kumar Gupta
- Department of Physics, Dr. Harisingh University, Sagar 470003, Madhya Pradesh, India.
| | - Abhijit P Deshpande
- Department of Chemical Engineering, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Ranveer Kumar
- Department of Physics, Dr. Harisingh University, Sagar 470003, Madhya Pradesh, India
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Park J, Sasaki Y, Ishii Y, Murayama S, Ohshiro K, Nishiura K, Ikura R, Yamaguchi H, Harada A, Matsuba G, Washizu H, Minami T, Takashima Y. Leaf-Inspired Host-Guest Complexation-Dictating Supramolecular Gas Sensors. ACS APPLIED MATERIALS & INTERFACES 2023; 15:39777-39785. [PMID: 37565809 DOI: 10.1021/acsami.3c04395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
We report unique conductive leaf-inspired (in particular, stomata-inspired) supramolecular gas sensors in which acetylated cyclodextrin derivatives rule the electric output. The gas sensors consist of polymers bearing acetylated cyclodextrin, adamantane, and carbon black. Host-guest complexes between acetylated cyclodextrin and adamantane corresponding to the closed stomata realize a flexible polymeric matrix. Effective recombination of the cross-links contributes to the robustness. As gas sensors, the supramolecular materials detect ammonia as well as various other gases at 1 ppm in 10 min. The free acetylated cyclodextrin corresponding to open stomata recognized the guest gases to alter the electric resistivity. Interestingly, the conductive device failed to detect ammonia gases at all without acetylated cyclodextrin. The molecular recognition was studied by molecular dynamics simulations. The gas molecules existed stably in the cavity of free acetylated cyclodextrin. These findings show the potential for developing wearable gas sensors.
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Affiliation(s)
- Junsu Park
- Department of Macromolecular Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
- Forefront Research Center, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Yui Sasaki
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
| | - Yoshiki Ishii
- Graduate School of Information Science, University of Hyogo, 7-1-28 minatojima-minamimachi, Chuo, Kobe, Hyogo 650-0047, Japan
| | - Shunsuke Murayama
- Graduate School of Organic Materials Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan
| | - Kohei Ohshiro
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
| | - Kengo Nishiura
- Graduate School of Organic Materials Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan
| | - Ryohei Ikura
- Department of Macromolecular Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
- Forefront Research Center, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Hiroyasu Yamaguchi
- Department of Macromolecular Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
- Forefront Research Center, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
- Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, 1-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Akira Harada
- Forefront Research Center, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
| | - Go Matsuba
- Graduate School of Organic Materials Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan
| | - Hitoshi Washizu
- Graduate School of Information Science, University of Hyogo, 7-1-28 minatojima-minamimachi, Chuo, Kobe, Hyogo 650-0047, Japan
| | - Tsuyoshi Minami
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
| | - Yoshinori Takashima
- Department of Macromolecular Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
- Institute for Advanced Co-Creation Studies, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
- Forefront Research Center, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
- Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, 1-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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Kimura T, Aoyama T, Nakahata M, Takashima Y, Tanaka M, Harada A, Urayama K. Time-strain inseparability in multiaxial stress relaxation of supramolecular gels formed via host-guest interactions. SOFT MATTER 2022; 18:4953-4962. [PMID: 35748314 DOI: 10.1039/d2sm00285j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Supramolecular hydrogels utilizing host-guest interactions (HG gels) exhibit large deformability and pronounced viscoelasticity. The inclusion complexes between β-cyclodextrin (host) and adamantane (guest) units on the water-soluble polymers form transient bonds. The HG gels show significant stress relaxation with finite equilibrium stress following the step strain. The stress relaxation process reflects the detachment dynamics of the transient bonds which sustain the initial stress, while the finite equilibrium stress is preserved by the permanent topological cross-links with a rotaxane structure. Nonlinear stress relaxation experiments in biaxial stretching with various combinations of two orthogonal strains unambiguously reveal that time and strain effects on stress are not separable. The relaxation is accelerated for a short time frame (<102 s) with an increase in the magnitude of strain, whereas it is retarded for a longer time window with an increase in the anisotropy of the imposed biaxial strain. The time-strain inseparability in the HG gels is in contrast to the simple nonlinear viscoelasticity of a dual cross-link gel with covalent and transient cross-links in which the separability was previously validated by the same assessment. We currently interpret that the significant susceptibility of the detachment dynamics to the deformation type results from the structural characteristics of the HG gels, i.e., the host and guest moieties covalently connected to the network chains, the considerably low concentrations (<0.1 M) of these moieties, and the slidability of the permanent rotaxane cross-links.
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Affiliation(s)
- Takuro Kimura
- Department of Macromolecular Science and Engineering, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585, Japan
| | - Takuma Aoyama
- Department of Macromolecular Science and Engineering, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585, Japan
| | - Masaki Nakahata
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 560-8531 Osaka, Japan
| | - Yoshinori Takashima
- Institute for Advanced Co-Creation Studies, Osaka University, Suita, Osaka 565-0871, Japan
| | - Motomu Tanaka
- Center for Integrative Medicine and Physics, Institute for Advanced Study, Kyoto University, 606-8501 Kyoto, Japan
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, Heidelberg University, D69120 Heidelberg, Germany
| | - Akira Harada
- The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Kenji Urayama
- Department of Macromolecular Science and Engineering, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585, Japan
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, 615-8510 Kyoto, Japan.
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