Remarkable interfacial dielectric relaxation of physically cross-linked ice hydrogels

Abstract

In the conventional scenario, it is believed that hydrogels typically consist of two-phase coexisting structures based on polymer structural networks filled with water droplets and that the polymer-water interfacial layer may not be a substantial component in determining their structure and functionality. Unfortunately, it is challenging to unveil the properties of the interfacial layer, if any, owing to the multiphase nature and structural complexity of hydrogels. In this work, the morphology and microstructures of the well-known non-covalent bonding dominant polyacrylonitrile-based hydrogels are characterized and it is confirmed that the as-prepared hydrogels do consist of polymer networks and filled water droplets. The dielectric relaxation behavior in the ice hydrogel state with different water/ice contents is investigated in detail by means of dielectric relaxation spectroscopy, in order to avoid the electrode polarization effect, which is non-negligible in liquid hydrogels, particularly in the low-frequency range. The dielectric relaxation spectroscopy data demonstrate the remarkable dielectric response contributed from the polymer-ice interfacial layer, which likely accommodates a high density of polar molecules/dipoles. The temperature-dependent dielectric relaxation behavior of the ice hydrogels with different water contents is discussed and the thermal activation energy for the interfacial polar structure may be likely extracted from the dielectric loss peak data. It is found that this energy is approximately consistent with the typical bonding energy of non-covalent bonding dominant hydrogels. This study represents a substantial step towards understanding the interfacial coupling in hydrogels, an issue that has not yet been thoroughly considered.

Keywords

Ice hydrogels / dielectric relaxation / polar molecules / interfacial layer

References

[1] Vázquez-González M.Stimuli-responsive biomolecule-based hydrogels and their applications.Angew Chem Int Ed Engl2020;59:15342-77

[2] Gong JP.Why are double network hydrogels so tough?.Soft Matter2010;6:2583

[3] Gong J,Kurokawa T.Double-network hydrogels with extremely high mechanical strength.Adv Mater2003;15:1155-8

[4] Zhang Y,Liu W.Dipole-dipole and H-bonding interactions significantly enhance the multifaceted mechanical properties of thermoresponsive shape memory hydrogels.Adv Funct Mater2015;25:471-80

[5] Qiu Y.Environment-sensitive hydrogels for drug delivery.Adv Drug Delivery Rev2001;53:321-39

[6] Chen Q,Zhu L.Fundamentals of double network hydrogels.J Mater Chem B2015;3:3654-76

[7] Balakrishnan B.Biopolymer-based hydrogels for cartilage tissue engineering.Chem Rev2011;111:4453-74

[8] Wegst UG,Saiz E,Ritchie RO.Bioinspired structural materials.Nat Mater2015;14:23-36

[9] Deng J,Wu J.Electrical bioadhesive interface for bioelectronics.Nat Mater2021;20:229-36

[10] Cao C,Li B,Wang L.Uncovering isolated resonant responses in antagonistic pure-shear dielectric elastomer actuators.Soft Sci2021;1:1-19

[11] Li G,Cai M.A stretchable and adhesive ionic conductor based on polyacrylic acid and deep eutectic solvents.npj Flex Electron2021;5:23

[12] Wang W,Liu W.Bioinspired fabrication of high strength hydrogels from non-covalent interactions.Prog Polym Sci2017;71:1-25

[13] Mati IK.Molecular balances for quantifying non-covalent interactions.Chem Soc Rev2010;39:4195-205

[14] Green JJ.Mimicking biological functionality with polymers for biomedical applications.Nature2016;540:386-94 PMCID:PMC8186828

[15] Rosales AM.The design of reversible hydrogels to capture extracellular matrix dynamics.Nat Rev Mater2016;1:15012 PMCID:PMC5714327

[16] Tang L,Liu G.High-strength hydrogels with integrated functions of H-bonding and thermoresponsive surface-mediated reverse transfection and cell detachment.Adv Mater2010;22:2652-6

[17] Wang X,Yang Y,Wu D.Fabrication of multi-stimuli responsive supramolecular hydrogels based on host–guest inclusion complexation of a tadpole-shaped cyclodextrin derivative with the azobenzene dimer.Polym Chem2017;8:3901-9

[18] Zhang Y,Wang H.Radiopaque highly stiff and tough shape memory hydrogel microcoils for permanent embolization of arteries.Adv Funct Mater2018;28:1705962

[19] Koetting MC,Steichen SD.Stimulus-responsive hydrogels: theory, modern advances, and applications.Mater Sci Eng R Rep2015;93:1-49 PMCID:PMC4847551

[20] Li J,Vlassak JJ.Stiff, strong, and tough hydrogels with good chemical stability.J Mater Chem B2014;2:6708-13

[21] Bai T,Han Y.Construction of an ultrahigh strength hydrogel with excellent fatigue resistance based on strong dipole-dipole interaction.Soft Matter2011;7:2825

[22] Lin P,Wang X.Molecularly engineered dual-crosslinked hydrogel with ultrahigh mechanical strength, toughness, and good self-recovery.Adv Mater2015;27:2054-9

[23] Vermonden T,Hennink WE.Hydrogels for protein delivery.Chem Rev2012;112:2853-88

[24] Kühlbrandt W.Biochemistry. The resolution revolution.Science2014;343:1443-4

[25] O'Reilly FJ,Graziadei A.In-cell architecture of an actively transcribing-translating expressome.Science2020;369:554-7 PMCID:PMC7115962

[26] Lyon LA,Fox AP.Raman spectroscopy.Anal Chem1998;70:341R-61R

[27] Paolini L,Consoli G.Fourier-transform Infrared (FT-IR) spectroscopy fingerprints subpopulations of extracellular vesicles of different sizes and cellular origin.J Extracell Vesicles2020;9:1741174 PMCID:PMC7170381

[28] De Francesco A,Lennox RB.Model-free description of polymer-coated gold nanoparticle dynamics in aqueous solutions obtained by Bayesian analysis of neutron spin echo data.Phys Rev E2019;99:052504

[29] Li Y,Jia P.Dielectric relaxation of interfacial polarizable molecules in chitosan ice-hydrogel materials.J Materiomices2018;4:35-43

[30] Zhou H,Jin X.Capacitive pressure sensors containing reliefs on solution-processable hydrogel electrodes.ACS Appl Mater Interfaces2021;13:1441-51

[31] Wang Y,Liu J,Guo D.Adaptive deformation of ionic domains in hydrogel enforcing dielectric coupling for sensitive response to mechanical stretching.Advanced Intelligent Systems2020;2:2000016

[32] Cai Y,Yin R,Zhang H.An enzyme-free capacitive glucose sensor based on dual-network glucose-responsive hydrogel and coplanar electrode.Analyst2021;146:213-21

[33] Ishai PB,Caduff A,Feldman Y.Electrode polarization in dielectric measurements: a review.Meas Sci Technol2013;24:102001

[34] Bai T,Zhang P,Liu W.Zinc ion-triggered two-way macro-/microscopic shape changing and memory effects in high strength hydrogels with pre-programmed unilateral patterned surfaces.Soft Matter2012;8:6846

[35] Malkin TL,Brukhno AV,Salzmann CG.Structure of ice crystallized from supercooled water.Proc Natl Acad Sci U S A2012;109:1041-5 PMCID:PMC3268266

[36] Gong Y,Mo G,Lü C.In-situ microstructural changes of polyacrylonitrile based fibers with stretching deformation.Polymer2014;55:4270-80

[37] Chaudhuri O.Viscoelastic hydrogels for 3D cell culture.Biomater Sci2017;5:1480-90

[38] Markel VA.Introduction to the Maxwell Garnett approximation: tutorial.J Opt Soc Am A Opt Image Sci Vis2016;33:1244-56

[39] Laidler KJ.The development of the Arrhenius equation.J Chem Educ1984;61:494

[40] Popov I,Khamzin A.The dynamic crossover in dielectric relaxation behavior of ice I(h).Phys Chem Chem Phys2015;17:1489-97

[41] Khamzin AA,Nikitin AS.Theoretical description of dielectric relaxation of ice with low concentration impurities.Chemical Physics2021;541:111040