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Varadarajan A, Badani Prado RM, Elmore K, Mishra S, Kundu S. Effects of concentration of hydrophobic component and swelling in saline solutions on mechanical properties of a stretchable hydrogel. SOFT MATTER 2024; 20:869-876. [PMID: 38170915 DOI: 10.1039/d3sm01215h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
An elastic biopolymer, resilin possesses exceptional qualities such as high stretchability and resilience. Such attributes are utilized in nature by many species for mechanical energy storage to facilitate movement. The properties of resilin are attributed to the balanced combination of hydrophilic and hydrophobic segments. To mimic the properties of resilin, we developed a hydrogel system composed of hydrophilic acrylic acid (AAc) and methacrylamide (MAM) chains and hydrophobic poly(propylene glycol diacrylate) (PPGDA) chains. The gel was produced through free-radical polymerization in 0.8 M NaCl solutions using KPS as an initiator. In these gels, AAc and MAM can form hydrogen bonds, whereas the association between PPGDA chains can lead to hydrophobic domains. The PPGDA concentration affects the level of hydrogen bonding and gel mechanical properties. Tensile experiments revealed that the elastic modulus increased with a higher PPGDA concentration. Retraction experiments demonstrated increased velocity and acceleration when released from a stretched state with increasing PPGDA concentration. Swelling and deswelling of gels in saline solutions led to a change in mechanical properties and retraction behavior. This study shows that the stretchability and resilience of these hydrogels can be adjusted by changing the concentration of hydrophobic components.
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Affiliation(s)
- Anandavalli Varadarajan
- Dave C Swalm School of Chemical Engineering, Mississippi State University, MS State, MS, 39762, USA.
| | - Rosa Maria Badani Prado
- Dave C Swalm School of Chemical Engineering, Mississippi State University, MS State, MS, 39762, USA.
| | - Katherine Elmore
- Dave C Swalm School of Chemical Engineering, Mississippi State University, MS State, MS, 39762, USA.
| | - Satish Mishra
- Dave C Swalm School of Chemical Engineering, Mississippi State University, MS State, MS, 39762, USA.
| | - Santanu Kundu
- Dave C Swalm School of Chemical Engineering, Mississippi State University, MS State, MS, 39762, USA.
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Keane DP, Constantine CJ, Mellor MD, Poling-Skutvik R. Bridging Heterogeneity Dictates the Microstructure and Yielding Response of Polymer-Linked Emulsions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:7852-7862. [PMID: 37204835 PMCID: PMC11331760 DOI: 10.1021/acs.langmuir.3c00707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Soft materials possessing tunable rheological properties are desirable in applications ranging from 3D printing to biological scaffolds. Here, we use a telechelic, triblock copolymer polystyrene-b-poly(ethylene oxide)-b-polystyrene (SEOS) to form elastic networks of polymer-linked droplets in cyclohexane-in-water emulsions. The SEOS endblocks partition into the dispersed cyclohexane droplets while the midblocks remain in the aqueous continuous phase, resulting in each chain taking on either a looping or bridging conformation. By controlling the fraction of chains that form bridges, we tune the linear elasticity of the emulsions and generate a finite yield stress. Polymers with higher molecular weight (Mw) endblocks form stronger interdroplet connections and display a higher bridging density. Beyond modifying the linear rheology, the telechelic, triblock copolymers also alter the yielding behavior and processability of the linked emulsions. We examine the yield transition of these polymer-linked emulsions through large amplitude oscillatory shear (LAOS) and probe the emulsion structure through confocal microscopy, concluding that polymers that more readily form bridges generate a strongly percolated network, whereas those that are less prone to form bridges tend to produce networks composed of weakly linked clusters of droplets. When yielded, the emulsions consisting of linked clusters break apart into individual clusters that can rearrange upon the application of further shear. By contrast, when the systems containing a more homogeneous bridging density are yielded, the system remains percolated but with reduced elasticity and bridging density. The demonstrated ability of telechelic triblock copolymers to tune not only the linear viscoelasticity of complex fluids but also their nonlinear yield transition enables the use of these polymers as versatile and robust rheological modifiers. We expect our findings to therefore aid the design of the next generation of complex fluids and soft materials.
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Affiliation(s)
- Daniel P Keane
- Department of Chemical Engineering, University of Rhode Island, Kingston, Rhode Island 02881, United States
| | - Colby J Constantine
- Department of Chemical Engineering, University of Rhode Island, Kingston, Rhode Island 02881, United States
| | - Matthew D Mellor
- Department of Chemical Engineering, University of Rhode Island, Kingston, Rhode Island 02881, United States
| | - Ryan Poling-Skutvik
- Department of Chemical Engineering, University of Rhode Island, Kingston, Rhode Island 02881, United States
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Badani Prado RM, Mishra S, Ahmed H, Burghardt WR, Kundu S. Temperature- and strain-dependent transient microstructure and rheological responses of endblock-associated triblock gels of different block lengths in a midblock selective solvent. SOFT MATTER 2022; 18:7020-7034. [PMID: 36070440 DOI: 10.1039/d2sm00567k] [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
Endblock associative ABA gels in midblock selective solvents are attractive due to their easily tunable mechanical properties. Here, we present the effects of A- and B-block lengths on the rheological properties and microstructure of ABA gels by considering three low and one high polymer concentrations. The triblock polymer considered is poly(methyl methacrylate)-poly(n-butyl acrylate)-poly(methyl methacrylate) [PMMA-PnBA-PMMA] and the midblock solvent is 2-ethyl-1-hexanol. The gelation temperature has been found to be strongly dependent on the B-block (PnBA) length, as longer B-blocks facilitate network formation resulting in higher gelation temperature even with lower polymer chain density. Longer A-blocks (PMMA chains) make the endblock association stronger and significantly increase the relaxation time of gels. Temperature-dependent microstructure evolution for the gels with high polymer concentration reveals that the gel microstructure does not change significantly after the gel formation takes place. The dynamic change of microstructure in an applied strain cycle was captured using RheoSAXS experiments. The microstructure orients with the applied strain and the process is reversible in nature, indicating no significant A-block pullout. Our results provide new understandings regarding the temperature and strain-dependent microstructural change of ABA gels in midblock selective solvents.
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Affiliation(s)
- Rosa Maria Badani Prado
- Dave C. Swalm School of Chemical Engineering, 323 Presidents Circle, Mississippi State University, Mississippi State, MS 39762, USA.
| | - Satish Mishra
- Dave C. Swalm School of Chemical Engineering, 323 Presidents Circle, Mississippi State University, Mississippi State, MS 39762, USA.
| | - Humayun Ahmed
- Dave C. Swalm School of Chemical Engineering, 323 Presidents Circle, Mississippi State University, Mississippi State, MS 39762, USA.
| | - Wesley R Burghardt
- Department of Chemical Engineering, Northwestern University, Evanston, IL, USA
| | - Santanu Kundu
- Dave C. Swalm School of Chemical Engineering, 323 Presidents Circle, Mississippi State University, Mississippi State, MS 39762, USA.
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Zhao Y, Ma Y, Xiong Y, Qin T, Zhu Y, Deng H, Qin J, Shi X, Zhang G. Chemically crosslinked crystalline thermoplastic polyolefin elastomer with good elasticity and improved thermo-mechanical properties. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.125075] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Steube M, Johann T, Barent RD, Müller AH, Frey H. Rational design of tapered multiblock copolymers for thermoplastic elastomers. Prog Polym Sci 2022. [DOI: 10.1016/j.progpolymsci.2021.101488] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Prado RMB, Mishra S, Ahmad H, Burghardt WR, Kundu S. Capturing the Transient Microstructure of a Physically Assembled Gel Subjected to Temperature and Large Deformation. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00895] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Rosa Maria Badani Prado
- Dave C. Swalm School of Chemical Engineering, Mississippi State University, Mississippi State, Mississippi 39762, United States
| | - Satish Mishra
- Dave C. Swalm School of Chemical Engineering, Mississippi State University, Mississippi State, Mississippi 39762, United States
| | - Humayun Ahmad
- Dave C. Swalm School of Chemical Engineering, Mississippi State University, Mississippi State, Mississippi 39762, United States
| | - Wesley R. Burghardt
- Department of Chemical Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Santanu Kundu
- Dave C. Swalm School of Chemical Engineering, Mississippi State University, Mississippi State, Mississippi 39762, United States
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Prado RMB, Mishra S, Morgan B, Wijayapala R, Hashemnejad SM, Kundu S. Achieving High-Speed Retraction in Stretchable Hydrogels. ACS APPLIED MATERIALS & INTERFACES 2020; 12:40719-40727. [PMID: 32805889 DOI: 10.1021/acsami.0c08132] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Hydrogels mimicking elastomeric biopolymers such as resilin, responsible for power-amplified activities in biological species necessary for locomotion, feeding, and defense have applications in soft robotics and prosthetics. Here, we report a bioinspired hydrogel synthesized through a free-radical polymerization reaction. By maintaining a balance between the hydrophilic and hydrophobic components, we obtain gels with an elastic modulus as high as 100 kPa, stretchability up to 800%, and resilience up to 98%. Such properties enable these gels to catapult projectiles. Furthermore, these gels achieve a retraction velocity of 16 m s-1 with an acceleration of 4 × 103 m s-2 when released from a stretched state, and these values are comparable to those observed in many biological species during a power amplification process. By utilizing and tuning the simple synthetic strategy used here, these gels can be used in soft robotics, prosthetics, and engineered devices where power amplification is desired.
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Affiliation(s)
- Rosa Maria Badani Prado
- Dave C. Swalm School of Chemical Engineering, Mississippi State University, 323 Presidents Circle, Mississippi State, Mississippi 39762, United States
| | - Satish Mishra
- Dave C. Swalm School of Chemical Engineering, Mississippi State University, 323 Presidents Circle, Mississippi State, Mississippi 39762, United States
| | - Buckston Morgan
- Dave C. Swalm School of Chemical Engineering, Mississippi State University, 323 Presidents Circle, Mississippi State, Mississippi 39762, United States
| | - Rangana Wijayapala
- Dave C. Swalm School of Chemical Engineering, Mississippi State University, 323 Presidents Circle, Mississippi State, Mississippi 39762, United States
| | - Seyed Meysam Hashemnejad
- Dave C. Swalm School of Chemical Engineering, Mississippi State University, 323 Presidents Circle, Mississippi State, Mississippi 39762, United States
| | - Santanu Kundu
- Dave C. Swalm School of Chemical Engineering, Mississippi State University, 323 Presidents Circle, Mississippi State, Mississippi 39762, United States
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Hashemnejad SM, Kundu S. Rheological properties and failure of alginate hydrogels with ionic and covalent crosslinks. SOFT MATTER 2019; 15:7852-7862. [PMID: 31531488 DOI: 10.1039/c9sm01039d] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Polysaccharide-based hydrogels are being used in a wide variety of applications ranging from tissue engineering to food products due to their biocompatibility and the ease of gel formation. In real-life applications, hydrogels can undergo large strain deformation, which may result in structural damage leading to failure. Here, we report the nonlinear rheological properties and failure behavior of alginate hydrogels, a class of polysaccharide hydrogels, synthesized via ionic and covalent crosslinking. Gels with ionic crosslinks or ionic alginate hydrogels are prepared by addition of Ca2+ ions in the aqueous solution of sodium alginate, and the covalently crosslinked alginate gels or chemical alginate hydrogels are obtained via amidation reactions. Because of their structural differences, ionic and chemical alginate hydrogels display different scattering profiles captured by using small angle X-ray scattering (SAXS) technique. Both ionic and chemical alginate hydrogels exhibit strain stiffening behavior when subjected to large amplitude oscillatory shear (LAOS) and the strain-stiffening behavior is accompanied by negative normal stress. A custom-built cavitation rheometer has been utilized to probe the local failure behavior of these gels. The cavitation rheometry captures different defect growth or fracture mechanism in ionic versus chemical alginate hydrogels, even if these two types of gels have a similar linear elastic modulus. Based on the critical pressure for gel fracture, we have provided an estimate of the critical energy release rate.
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Affiliation(s)
- Seyed Meysam Hashemnejad
- Dave C. Swalm School of Chemical Engineering, Mississippi State University, MS State, Starkville, Mississippi 39762, USA.
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Wijayapala R, Mishra S, Elmore B, Freeman C, Kundu S. Synthesis and characterization of crosslinked polymers from cottonseed oil. J Appl Polym Sci 2019. [DOI: 10.1002/app.47655] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Rangana Wijayapala
- Dave C. Swalm School of Chemical EngineeringMississippi State University Mississippi State Mississippi 39762
| | - Satish Mishra
- Dave C. Swalm School of Chemical EngineeringMississippi State University Mississippi State Mississippi 39762
| | - Bill Elmore
- Dave C. Swalm School of Chemical EngineeringMississippi State University Mississippi State Mississippi 39762
| | - Charles Freeman
- School of Human SciencesMississippi State University Mississippi State Mississippi, 39762
| | - Santanu Kundu
- Dave C. Swalm School of Chemical EngineeringMississippi State University Mississippi State Mississippi 39762
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