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Gabrielli V, Kuraite A, da Silva MA, Edler KJ, Angulo J, Nepravishta R, Muñoz-García JC, Khimyak YZ. Spin diffusion transfer difference (SDTD) NMR: An advanced method for the characterisation of water structuration within particle networks. J Colloid Interface Sci 2021; 594:217-227. [PMID: 33756365 DOI: 10.1016/j.jcis.2021.02.094] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 02/13/2021] [Accepted: 02/23/2021] [Indexed: 11/26/2022]
Abstract
HYPOTHESIS The classical STD NMR protocol to monitor solvent interactions in gels is strongly dependent on gelator and solvent concentrations and does not report on the degree of structuration of the solvent at the particle/solvent interface. We hypothesised that, for suspensions of large gelator particles, solvent structuration could be characterised by STD NMR when taking into account the particle-to-solvent 1H-1H spin diffusion transfer using the 1D diffusion equation. EXPERIMENTS We have carried out a systematic study on effect of gelator and solvent concentrations, and gelator surface charge, affecting the behaviour of the classical STD NMR build-up curves. To do so, we have characterised solvent interactions in dispersions of starch and cellulose-like particles prepared in deuterated water and alcohol/D2O mixtures. FINDINGS The Spin Diffusion Transfer Difference (SDTD) NMR protocol is independent of the gelator and solvent concentrations, hence allowing the estimation of the degree of solvent structuration within different particle networks. In addition, the simulation of SDTD build-up curves using the general one-dimensional diffusion equation allows the determination of minimum distances (r) and spin diffusion rates (D) at the particle/solvent interface. This novel NMR protocol can be readily extended to characterise the solvent(s) organisation in any type of colloidal systems constituted by large particles.
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Affiliation(s)
- Valeria Gabrielli
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Agne Kuraite
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | | | - Karen J Edler
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Jesús Angulo
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Ridvan Nepravishta
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK.
| | - Juan C Muñoz-García
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK.
| | - Yaroslav Z Khimyak
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK.
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Haraguchi K, Kimura Y. New Aqueous Solutions with Lower Viscosities than Water. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2021. [DOI: 10.1246/bcsj.20200396] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Kazutoshi Haraguchi
- Department of Applied Molecular Chemistry, College of Industrial Technology, Nihon University, 1-2-1 Izumi-cho, Narashino, Chiba 275-8575, Japan
| | - Yuji Kimura
- Department of Applied Molecular Chemistry, College of Industrial Technology, Nihon University, 1-2-1 Izumi-cho, Narashino, Chiba 275-8575, Japan
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Wei P, Chen T, Chen G, Liu H, Mugaanire IT, Hou K, Zhu M. Conductive Self-Healing Nanocomposite Hydrogel Skin Sensors with Antifreezing and Thermoresponsive Properties. ACS APPLIED MATERIALS & INTERFACES 2020; 12:3068-3079. [PMID: 31869196 DOI: 10.1021/acsami.9b20254] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
With growing interest in flexible and wearable devices, the demand for nature-inspired soft smart materials, especially intelligent hydrogels with multiple perceptions toward external strain and temperatures to mimic the human skin, is on the rise. However, simultaneous achievement of intelligent hydrogels with skin-compatible performances, including good transparency, appropriate mechanical properties, autonomous self-healing ability, multiple mechanical/thermoresponsiveness, and retaining flexibility at subzero temperatures, is still challenging and thus limits their application as skinlike devices. Here, conductive nanocomposite hydrogels (NC gels) were delicately designed and prepared via gelation of oligo(ethylene glycol) methacrylate (OEGMA)-based monomers in a glycerol-water cosolvent, where inorganic clay served as the physical cross-linker and provided conductive ions. The resultant NC gels exhibited good conductivity (∼3.32 × 10-4 S cm-1, akin to biological muscle tissue) and an autonomously self-healing capacity (healing efficiency reached 84.8%). Additionally, such NC gels displayed excellent flexibility and responded well to multiple strain/temperature external stimuli and subtle human motions in a wide temperature range (from -20 to 45 °C). These distinguished properties would endow such NC gels significant applications in fields of biosensors, human-machine interfaces, and soft robotics.
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Affiliation(s)
- Peiling Wei
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering , Donghua University , 2999 North Renmin Road , Shanghai 201620 , P. R. China
| | - Tao Chen
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering , Donghua University , 2999 North Renmin Road , Shanghai 201620 , P. R. China
| | - Guoyin Chen
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering , Donghua University , 2999 North Renmin Road , Shanghai 201620 , P. R. China
| | - Hongmei Liu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering , Donghua University , 2999 North Renmin Road , Shanghai 201620 , P. R. China
| | - Innocent Tendo Mugaanire
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering , Donghua University , 2999 North Renmin Road , Shanghai 201620 , P. R. China
| | - Kai Hou
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering , Donghua University , 2999 North Renmin Road , Shanghai 201620 , P. R. China
| | - Meifang Zhu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering , Donghua University , 2999 North Renmin Road , Shanghai 201620 , P. R. China
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Pujala RK, Bohidar HB. Hierarchical self-assembly, spongy architecture, liquid crystalline behaviour and phase diagram of Laponite nanoplatelets in alcohol-water binary solvents. J Colloid Interface Sci 2019; 554:731-742. [PMID: 31374517 DOI: 10.1016/j.jcis.2019.07.040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 06/10/2019] [Accepted: 07/15/2019] [Indexed: 10/26/2022]
Abstract
Hydrophobicity and solvation of different charged species are among the various key factors that regulate the self-assembly of colloids, and macromolecules in their suspensions. In this paper, we demonstrate a method to tune the interaction potential and the resulting phase behaviour and microstructure of the states that form by using a combination of Laponite nanoplatelets and alcohols in water. This allows us to exquisitely control the self-assembly process of Laponite nanoplatelets. A new class of soft materials, called nanoclay-organogels, is studied systematically for their aging behaviour, microscopic structure and mechanical properties. Real space imaging techniques depicted spongy architecture with nano and micron size pores inside the gel matrix indicating the hierarchical self-assembly of the nanoplatelets in the aqueous solutions of polar organics. We have extensively examined the dispersion stability, aggregation, gelation and liquid crystalline behaviour of Laponite nanoplatelets in different alcohol (methanol, ethanol, 1-proponaol and ethylene glycol, and glycerol)-water binary solvents, thereby proposing a generalized description of nanoclay in alcoholic solutions, which is poorly probed and marginally understood in the literature. A phase diagram of Laponite® in alcohol solutions is proposed, which clearly demarcates regions of isotropic sol, unstable sol, isotropic gel, nematic/birefringent gel, glass, flocculated sedimentation and liquid crystalline structures.
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Affiliation(s)
- Ravi Kumar Pujala
- Soft and Active Matter Group, Department of Physics, Indian Institute of Science Education and Research (IISER) Tirupati, Andhra Pradesh 517507, India.
| | - H B Bohidar
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110 067, India
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da Silva MA, Calabrese V, Schmitt J, Celebi D, Scott JL, Edler KJ. Alcohol induced gelation of TEMPO-oxidized cellulose nanofibril dispersions. SOFT MATTER 2018; 14:9243-9249. [PMID: 30418451 DOI: 10.1039/c8sm01815d] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Solvent-induced physical hydrogels of TEMPO-oxidized cellulose nanofibrils (OCNFs) were obtained from aqueous/alcoholic dispersions of fibrils in lower alcohols, namely, methanol, ethanol, 1-propanol and 2-propanol. The sol-gel transition occurs above a critical alcohol concentration of ca. 30 wt% for all alcohols tested. The rheological properties of the hydrogels depend on the nature of the alcohol: for ethanol, 1-propanol and 2-propanol the magnitude of the shear storage modulus follows the alcohol hydrophilicity, whilst methanol produces the weakest gels in the group. Above a second critical concentration, ca. 60 wt% alcohol, phase separation is observed as the gels undergo syneresis. Analysis of small-angle X-ray scattering data shows that the OCNFs may be modelled as rigid rods. In the presence of lower alcohols, attractive interactions between nanofibrils are present and, above the alcohol concentration leading to gelation, an increase of the OCNF cross-section is observed, suggesting alcohol induced aggregation of nanofibrils.
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Affiliation(s)
- Marcelo A da Silva
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
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