1
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Roussel S, Udabe J, Bin Sabri A, Calderón M, Donnelly R. Leveraging novel innovative thermoresponsive polymers in microneedles for targeted intradermal deposition. Int J Pharm 2024; 652:123847. [PMID: 38266945 DOI: 10.1016/j.ijpharm.2024.123847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/19/2024] [Accepted: 01/21/2024] [Indexed: 01/26/2024]
Abstract
Microneedles have garnered considerable attention over the years as a versatile pharmaceutical platform that could be leveraged to deliver drugs into and across the skin. In the current work, poly (N-isopropylacrylamide) (PNIPAm) is synthesized and characterized as a novel material for the development of a physiologically responsive microneedle-based drug delivery system. Typically, this polymer transitions reversibly between a swell state at lower temperatures and a more hydrophobic state at higher temperatures, enabling precise drug release. This study demonstrates that dissolving microneedles patches made from PNIPAm, incorporating BIS-PNIPAm, a crosslinked polymer variant, exhibit enhanced mechanical properties, evident from a smaller height reduction in microneedle (∼10 %). Although microneedles using PNIPAm alone were achievable, it displayed poor mechanical strength, requiring the inclusion of additional polymeric excipients like PVA to enhance mechanical properties. In addition, the incorporation of a thermoresponsive polymer did not have a significant (p > 0.05) impact on the insertion properties of the needles as all formulations inserted to a similar depth of 500 µm into ex vivo skin. Furthering this, the needles were loaded with a model payload, 1,1'-dioctadecyl-3,3,3',3'-tetramethylindodicarbocyanine perchlorate (DID) and the deposition of the cargo was monitored via multiphoton microscopy that showed that a deposit is formed at a depth of ≈200 µm. Also, it was revealed that crosslinked-PNIPAm (Bis-PNIPAm) formulations exhibited notable skin accumulationof the dye only after 4 h, independent of the excipient matrix used. This phenomenon was absent in non-crosslinked PNIPAm formulations, indicating a deposit formation in Bis-PNIPAm microneedle formulation. Collectively, this proof-of-concept study has advanced our understanding on the possibility to use PNIPAm for dissolving microneedle fabrication which could be harnessed for the deposition of nanoparticles into the dermis, for extended drug release within the skin.
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Affiliation(s)
- Sabrina Roussel
- Faculty of Pharmacy, CHU de Quebec Research Center, Université Laval, 2705 Laurier Blvd, Quebec G1V 4G2, Canada; School of Pharmacy, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK
| | - Jakes Udabe
- School of Pharmacy, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK; POLYMAT, Applied Chemistry Department, Faculty of Chemistry, University of the Basque Country UPV/EHU, Donostia - San Sebastián, Spain
| | - Akmal Bin Sabri
- School of Pharmacy, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK; Division of Advanced Materials and Healthcare Technologies, School of Pharmacy, The University of Nottingham, NG7 2RD, UK
| | - Marcelo Calderón
- POLYMAT, Applied Chemistry Department, Faculty of Chemistry, University of the Basque Country UPV/EHU, Donostia - San Sebastián, Spain; IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Ryan Donnelly
- School of Pharmacy, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK.
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2
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Minato H, Ushida S, Yokouchi K, Suzuki D. Multi-layer core/shell microgels with internal complexity and their nanocomposites. Chem Commun (Camb) 2024; 60:1630-1633. [PMID: 38234227 DOI: 10.1039/d3cc05579e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
In this study, we show that core/shell (CS) microgels with multiple layers can be created via a one-pot precipitation polymerization, in which monomers are added to the reaction flask multiple times once most of the previous monomer has been consumed. The complex internal structures of the microgels were examined using a combination of scattering and microscopy techniques.
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Affiliation(s)
- Haruka Minato
- Graduate School of Textile Science & Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan.
| | - Satoki Ushida
- Graduate School of Textile Science & Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan.
| | - Kentaro Yokouchi
- Graduate School of Textile Science & Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan.
| | - Daisuke Suzuki
- Graduate School of Textile Science & Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan.
- Research Initiative for Supra-Materials, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan
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3
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Yamamoto A, Inui T, Suzuki D, Urayama K. Stress-independent delay time in yielding of dilute colloidal gels. SOFT MATTER 2023; 19:9082-9091. [PMID: 37987474 DOI: 10.1039/d3sm01238g] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
We investigate the yielding under shear for dilute poly(N-isopropyl acrylamide-co-fumaric acid) (PNIPAM-FAc) colloidal gels obtained above the volume phase transition temperature. In this temperature range, the microgel suspensions form colloidal gels due to hydrophobic interparticle interactions under appropriate pH and ionic strength conditions. Step-strain tests revealed that yielding occurs when the applied strain exceeds a specific threshold, requiring a finite, stress-independent delay time (tD). This is distinct from previous findings on delayed yielding in other colloidal gels, where tD decreases with increasing stress. In the start-up shear tests, yield strain (γy) at a higher strain rate () increases with escalating , while γy at lower remains constant. This characteristic γy- relationship is successfully explained by a simple model using the stress-independent tD value without an adjustable fitting parameter. The distinctive yielding behavior, underscored by a stress-independent tD, is expected to originate from strain-induced macroscopic phase separation into a dense colloidal gel and water, observable separately from rheological measurements.
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Affiliation(s)
- Atsushi Yamamoto
- Department of Macromolecular Science and Engineering, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585, Japan
| | - Takumi Inui
- Graduate School of Textile Science & Technology, Shinshu University, Ueda 386-8567, Japan.
| | - Daisuke Suzuki
- Graduate School of Textile Science & Technology, Shinshu University, Ueda 386-8567, Japan.
- Research Initiative for Supra-Materials, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Ueda 386-8567, Japan
| | - Kenji Urayama
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.
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Kawamoto T, Yanagi K, Nishizawa Y, Minato H, Suzuki D. The compression of deformed microgels at an air/water interface. Chem Commun (Camb) 2023; 59:13289-13292. [PMID: 37830179 DOI: 10.1039/d3cc03425a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
The compression of deformed hydrogel microspheres (microgels) at air/water interfaces was investigated using a Langmuir-Blodgett trough with simultaneous in situ visualization of the process using a fluorescent microscope. The relationship between the structure of the microgel arrays and the compression behavior was clarified using microgels with different degrees of crosslinking.
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Affiliation(s)
- Takahisa Kawamoto
- Graduate School of Textile Science & Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan
| | - Kohei Yanagi
- Graduate School of Textile Science & Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan
| | - Yuichiro Nishizawa
- Graduate School of Textile Science & Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan
| | - Haruka Minato
- Graduate School of Textile Science & Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan
| | - Daisuke Suzuki
- Graduate School of Textile Science & Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan
- Research Initiative for Supra-Materials, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan.
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5
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Bhat B, Pahari S, Kwon JSI, Akbulut MES. Stimuli-responsive viscosity modifiers. Adv Colloid Interface Sci 2023; 321:103025. [PMID: 37871381 DOI: 10.1016/j.cis.2023.103025] [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: 04/18/2023] [Revised: 09/01/2023] [Accepted: 10/10/2023] [Indexed: 10/25/2023]
Abstract
Stimuli responsive viscosity modifiers entail an important class of materials which allow for smart material formation utilizing various stimuli for switching such as pH, temperature, light and salinity. They have seen applications in the biomedical space including tissue engineering and drug delivery, wherein stimuli responsive hydrogels and polymeric vessels have been extensively applied. Applications have also been seen in other domains like the energy sector and automobile industry, in technologies such as enhanced oil recovery. The chemistry and microstructural arrangements of the aqueous morphologies of dissolved materials are usually sensitive to the aforementioned stimuli which subsequently results in rheological sensitivity as well. Herein, we overview different structures capable of viscosity modification as well as go over the rheological theory associated with classical systems studied in literature. A detailed analysis allows us to explore correlations between commonly discussed models such as molecular packing parameter, tube reptation and stress relaxation with structural and rheological changes. We then present five primary mechanisms corresponding to stimuli responsive viscosity modification: (i) packing parameter modification via functional group conditioning and (ii) via dynamic bond formation, (iii) mesh formation by interlinking of network nodes, (iv) viscosity modification by chain conformation changes and (v) viscosity modification by particle jamming. We also overview several recent examples from literature that employ the concepts discussed to create novel classes of intriguing stimuli responsive structures and their corresponding rheological properties. Furthermore, we also explore systems that are responsive to multiple stimuli which can provide enhanced functionality and versatility by providing multi-level and precise actuation. Such systems have been used for programmed site-specific drug delivery.
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Affiliation(s)
- Bhargavi Bhat
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Silabrata Pahari
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Joseph Sang-Il Kwon
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, USA; Texas A&M Energy Institute, College Station, TX 77843, USA
| | - Mustafa E S Akbulut
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, USA; Department of Materials Science and Engineering, Texas A&M University, College Station, TX 77843, USA; Texas A&M Energy Institute, College Station, TX 77843, USA.
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6
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Akgonullu DZ, Murray BS, Connell SD, Fang Y, Linter B, Sarkar A. Synthetic and biopolymeric microgels: Review of similarities and difference in behaviour in bulk phases and at interfaces. Adv Colloid Interface Sci 2023; 320:102983. [PMID: 37690329 DOI: 10.1016/j.cis.2023.102983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 08/12/2023] [Accepted: 08/14/2023] [Indexed: 09/12/2023]
Abstract
This review discusses the current knowledge of interfacial and bulk interactions of biopolymeric microgels in relation to the well-established properties of synthetic microgels for applications as viscosity modifiers and Pickering stabilisers. We present a timeline showing the key milestones in designing microgels and their bulk/ interfacial performance. Poly(N-isopropylacrylamide) (pNIPAM) microgels have remained as the protagonist in the synthetic microgel domain whilst proteins or polysaccharides have been primarily used to fabricate biopolymeric microgels. Bulk properties of microgel dispersions are dominated by the volume fraction (ϕ) of the microgel particles, but ϕ is difficult to pinpoint, as addressed by many theoretical models. By evaluating recent experimental studies over the last five years, we find an increasing focus on the analysis of microgel elasticity as a key parameter in modulating their packing at the interfaces, within the provinces of both synthetic and biopolymeric systems. Production methods and physiochemical factors shown to influence microgel swelling in the aqueous phase can have a significant impact on their bulk as well as interfacial performance. Compared to synthetic microgels, biopolymer microgels show a greater tendency for polydispersity and aggregation and do not appear to have a core-corona structure. Comprehensive studies of biopolymeric microgels are still lacking, for example, to accurately determine their inter- and intra- particle interactions, whilst a wider variety of techniques need to be applied in order to allow comparisons to real systems of practical usage.
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Affiliation(s)
- Daisy Z Akgonullu
- Food Colloids and Bioprocessing Group, School of Food Science and Nutrition, University of Leeds, UK
| | - Brent S Murray
- Food Colloids and Bioprocessing Group, School of Food Science and Nutrition, University of Leeds, UK
| | - Simon D Connell
- Molecular and Nanoscale Physics Group, School of Physics and Astronomy, University of Leeds, UK
| | - Yuan Fang
- PepsiCo, Valhalla, New York, NY, USA
| | | | - Anwesha Sarkar
- Food Colloids and Bioprocessing Group, School of Food Science and Nutrition, University of Leeds, UK.
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7
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Morozova SM, Gevorkian A, Kumacheva E. Design, characterization and applications of nanocolloidal hydrogels. Chem Soc Rev 2023. [PMID: 37464914 DOI: 10.1039/d3cs00387f] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
Nanocolloidal gels (NCGs) are an emerging class of soft matter, in which nanoparticles act as building blocks of the colloidal network. Chemical or physical crosslinking enables NCG synthesis and assembly from a broad range of nanoparticles, polymers, and low-molecular weight molecules. The synergistic properties of NCGs are governed by nanoparticle composition, dimensions and shape, the mechanism of nanoparticle bonding, and the NCG architecture, as well as the nature of molecular crosslinkers. Nanocolloidal gels find applications in soft robotics, bioengineering, optically active coatings and sensors, optoelectronic devices, and absorbents. This review summarizes currently scattered aspects of NCG formation, properties, characterization, and applications. We describe the diversity of NCG building blocks, discuss the mechanisms of NCG formation, review characterization techniques, outline NCG fabrication and processing methods, and highlight most common NCG applications. The review is concluded with the discussion of perspectives in the design and development of NCGs.
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Affiliation(s)
- Sofia M Morozova
- N.E. Bauman Moscow State Technical University, 5/1 2-nd Baumanskaya street, 105005, Moscow, Russia
- Department of Chemistry University of Toronto, 80 Saint George street, Toronto, Ontario M5S 3H6, Canada.
| | - Albert Gevorkian
- Department of Chemistry University of Toronto, 80 Saint George street, Toronto, Ontario M5S 3H6, Canada.
| | - Eugenia Kumacheva
- Department of Chemistry University of Toronto, 80 Saint George street, Toronto, Ontario M5S 3H6, Canada.
- Department of Chemical Engineering and Applied Chemistry University of Toronto, 200 College street, Toronto, Ontario M5S 3E5, Canada
- The Institute of Biomaterials and Biomedical Engineering University of Toronto, 4 Taddle Creek Road, Toronto, Ontario M5S 3G9, Canada
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8
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Xu H, Li Y, Liu C, Zhu L, Zhou F, Yao E. Performance evaluation of oil-displacement viscoelastic zwitterionic surfactant fracturing fluid. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2023.121545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
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9
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Li S, Song Q, Liu K, Zhang Y, Zhao G, Zhou Y. Emulsion-templated oleogels generated through solvent exchange: Effects of miscibility of alcohols and oils. Lebensm Wiss Technol 2023. [DOI: 10.1016/j.lwt.2023.114545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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10
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Yurdasiper A, Şahiner A, Gökçe EH. Preparation of thermoresponsive triclosan poly (N-isopropylacrylamide) nanogels and evaluation of antibacterial efficacy on Cutibacterium acnes. J Drug Deliv Sci Technol 2022. [DOI: 10.1016/j.jddst.2022.103734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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11
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Xu Y, Zhu H, Denduluri A, Ou Y, Erkamp NA, Qi R, Shen Y, Knowles TPJ. Recent Advances in Microgels: From Biomolecules to Functionality. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2200180. [PMID: 35790106 DOI: 10.1002/smll.202200180] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 03/15/2022] [Indexed: 06/15/2023]
Abstract
The emerging applications of hydrogel materials at different length scales, in areas ranging from sustainability to health, have driven the progress in the design and manufacturing of microgels. Microgels can provide miniaturized, monodisperse, and regulatable compartments, which can be spatially separated or interconnected. These microscopic materials provide novel opportunities for generating biomimetic cell culture environments and are thus key to the advances of modern biomedical research. The evolution of the physical and chemical properties has, furthermore, highlighted the potentials of microgels in the context of materials science and bioengineering. This review describes the recent research progress in the fabrication, characterization, and applications of microgels generated from biomolecular building blocks. A key enabling technology allowing the tailoring of the properties of microgels is their synthesis through microfluidic technologies, and this paper highlights recent advances in these areas and their impact on expanding the physicochemical parameter space accessible using microgels. This review finally discusses the emerging roles that microgels play in liquid-liquid phase separation, micromechanics, biosensors, and regenerative medicine.
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Affiliation(s)
- Yufan Xu
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Hongjia Zhu
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Akhila Denduluri
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Yangteng Ou
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Nadia A Erkamp
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Runzhang Qi
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Yi Shen
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, NSW, 2006, Australia
- The University of Sydney Nano Institute, University of Sydney, Sydney, NSW, 2006, Australia
| | - Tuomas P J Knowles
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
- Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE, UK
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12
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Scotti A, Schulte MF, Lopez CG, Crassous JJ, Bochenek S, Richtering W. How Softness Matters in Soft Nanogels and Nanogel Assemblies. Chem Rev 2022; 122:11675-11700. [PMID: 35671377 DOI: 10.1021/acs.chemrev.2c00035] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Softness plays a key role in determining the macroscopic properties of colloidal systems, from synthetic nanogels to biological macromolecules, from viruses to star polymers. However, we are missing a way to quantify what the term "softness" means in nanoscience. Having quantitative parameters is fundamental to compare different systems and understand what the consequences of softness on the macroscopic properties are. Here, we propose different quantities that can be measured using scattering methods and microscopy experiments. On the basis of these quantities, we review the recent literature on micro- and nanogels, i.e. cross-linked polymer networks swollen in water, a widely used model system for soft colloids. Applying our criteria, we address the question what makes a nanomaterial soft? We discuss and introduce general criteria to quantify the different definitions of softness for an individual compressible colloid. This is done in terms of the energetic cost associated with the deformation and the capability of the colloid to isotropically deswell. Then, concentrated solutions of soft colloids are considered. New definitions of softness and new parameters, which depend on the particle-to-particle interactions, are introduced in terms of faceting and interpenetration. The influence of the different synthetic routes on the softness of nanogels is discussed. Concentrated solutions of nanogels are considered and we review the recent results in the literature concerning the phase behavior and flow properties of nanogels both in three and two dimensions, in the light of the different parameters we defined. The aim of this review is to look at the results on micro- and nanogels in a more quantitative way that allow us to explain the reported properties in terms of differences in colloidal softness. Furthermore, this review can give researchers dealing with soft colloids quantitative methods to define unambiguously which softness matters in their compound.
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Affiliation(s)
- Andrea Scotti
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany, European Union
| | - M Friederike Schulte
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany, European Union
| | - Carlos G Lopez
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany, European Union
| | - Jérôme J Crassous
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany, European Union
| | - Steffen Bochenek
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany, European Union
| | - Walter Richtering
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany, European Union
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13
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Echeverría C, Mijangos C. Rheology Applied to Microgels: Brief (Revision of the) State of the Art. Polymers (Basel) 2022; 14:1279. [PMID: 35406152 PMCID: PMC9003433 DOI: 10.3390/polym14071279] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 03/18/2022] [Accepted: 03/18/2022] [Indexed: 12/10/2022] Open
Abstract
The ability of polymer microgels to rapidly respond to external stimuli is of great interest in sensors, lubricants, and biomedical applications, among others. In most of their uses, microgels are subjected to shear, deformation, and compression forces or a combination of them, leading to variations in their rheological properties. This review article mainly refers to the rheology of microgels, from the hard sphere versus soft particles' model. It clearly describes the scaling theories and fractal structure formation, in particular, the Shih et al. and Wu and Morbidelli models as a tool to determine the interactions among microgel particles and, thus, the viscoelastic properties. Additionally, the most recent advances on the characterization of microgels' single-particle interactions are also described. The review starts with the definition of microgels, and a brief introduction addresses the preparation and applications of microgels and hybrid microgels.
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Affiliation(s)
- Coro Echeverría
- Instituto de Ciencia y Tecnología de Polímeros (ICTP-CSIC), C/Juan de la Cierva 3, 28006 Madrid, Spain;
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14
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Dang S, Brady J, Rel R, Surineni S, O'Shaughnessy C, McGorty R. Core-shell droplets and microcapsules formed through liquid-liquid phase separation of a colloid-polymer mixture. SOFT MATTER 2021; 17:8300-8307. [PMID: 34550150 DOI: 10.1039/d1sm01091c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Microcapsules allow for the controlled containment, transport, and release of cargoes ranging from pharmaceuticals to fragrances. Given the interest from a variety of industries in microcapsules and other core-shell structures, a multitude of fabrication strategies exist. Here, we report on a method relying on a mixture of temperature-responsive microgel particles, poly(N-isopropylacrylamide) (pNIPAM), and a polymer which undergo fluid-fluid phase separation. At room temperature this mixture separates into colloid-rich (liquid) and colloid-poor (gas) fluids. By heating the sample above a critical temperature where the microgel particles shrink dramatically and develop a more deeply attractive interparticle potential, the droplets of the colloid-rich phase become gel-like. As the temperature is lowered back to room temperature, these droplets of gelled colloidal particles reliquefy and phase separation within the droplet occurs. This phase separation leads to colloid-poor droplets within the colloid-rich droplets surrounded by a continuous colloid-poor phase. The gas/liquid/gas all-aqueous double emulsion lasts only a few minutes before a majority of the inner droplets escape. However, the colloid-rich shell of the core-shell droplets can solidify with the addition of salt. That this method creates core-shell structures with a shell composed of stimuli-sensitive microgel colloidal particles using only aqueous components makes it attractive for encapsulating biological materials and making capsules that respond to changes in, for example, temperature, salt concentration, or pH.
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Affiliation(s)
- Steven Dang
- Department of Physics and Biophysics, University of San Diego, San Diego, CA, 92110, USA.
| | - John Brady
- Department of Physics and Biophysics, University of San Diego, San Diego, CA, 92110, USA.
| | - Ryle Rel
- Department of Physics and Biophysics, University of San Diego, San Diego, CA, 92110, USA.
| | - Sreenidhi Surineni
- Department of Physics and Biophysics, University of San Diego, San Diego, CA, 92110, USA.
| | - Conor O'Shaughnessy
- Department of Physics and Biophysics, University of San Diego, San Diego, CA, 92110, USA.
| | - Ryan McGorty
- Department of Physics and Biophysics, University of San Diego, San Diego, CA, 92110, USA.
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15
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Frenzel L, Dartsch M, Balaguer GM, Westermeier F, Grübel G, Lehmkühler F. Glass-liquid and glass-gel transitions of soft-shell particles. Phys Rev E 2021; 104:L012602. [PMID: 34412357 DOI: 10.1103/physreve.104.l012602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 06/23/2021] [Indexed: 12/12/2022]
Abstract
We study the structure and dynamics of colloidal particles with a spherical hard core and a thermo-responsive soft shell over the whole phase diagram by means of small-angle x-ray scattering and x-ray photon correlation spectroscopy. By changing the effective volume fraction by temperature and particle concentration, liquid, repulsive glass. and attractive gel phases are observed. The dynamics slow down with increasing volume fraction in the liquid phase and reflect a Vogel-Fulcher-Tamann behavior known for fragile glass formers. We find a liquid-glass transition above 50 vol.% that is independent of the particles' concentration and temperature. In an overpacked state at effective volume fractions above 1, the dispersion does not show a liquid phase but undergoes a gel-glass transition at an effective volume fraction of 34 vol.%. At the same concentration, extrema of subdiffusive dynamics are found in the liquid phase at lower weight fractions. We interpret this as dynamic precursors of the glass-gel transition.
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Affiliation(s)
- Lara Frenzel
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.,The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Michael Dartsch
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.,The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
| | | | - Fabian Westermeier
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Gerhard Grübel
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.,The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Felix Lehmkühler
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.,The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
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16
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Affiliation(s)
- Yuichiro Nishizawa
- Graduate School of Textile Science & Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan
| | - Kenshiro Honda
- Graduate School of Textile Science & Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan
| | - Daisuke Suzuki
- Graduate School of Textile Science & Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan
- Research Initiative for Supra-Materials, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan
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17
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Chaudhary G, Ghosh A, Kang JG, Braun PV, Ewoldt RH, Schweizer KS. Linear and nonlinear viscoelasticity of concentrated thermoresponsive microgel suspensions. J Colloid Interface Sci 2021; 601:886-898. [PMID: 34186277 DOI: 10.1016/j.jcis.2021.05.111] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/26/2021] [Accepted: 05/19/2021] [Indexed: 11/25/2022]
Abstract
We present an integrated experimental and theoretical study of the dynamics and rheology of self-crosslinked, slightly charged, temperature responsive soft poly(N-isopropylacrylamide) (pNIPAM) microgels over a wide range of concentration and temperature spanning the sharp change in particle size and intermolecular interactions across the lower critical solution temperature (LCST). Dramatic, non-monotonic changes in viscoelasticity are observed as a function of temperature, with distinct concentration dependence in the dense fluid, glassy, and soft-jammed regimes. Motivated by our experimental observations, we formulate a minimalistic model for the size dependence of a single microgel particle and the change of the interparticle interaction from purely repulsive to attractive upon heating. Using microscopic equilibrium and time-dependent statistical mechanical theories, theoretical predictions are quantitatively compared with experimental measurements of the shear modulus. Good agreement is found for the nonmonotonic temperature behavior that originates as a consequence of the competition between reduced microgel packing fraction and increasing interparticle attractions. Testable predictions are made for nonlinear rheological properties such as the yield stress and strain. To our knowledge, this is the first attempt to quantitatively understand in a unified manner the viscoelasticity of dense, temperature-responsive microgel suspensions spanning a wide range of temperatures and concentrations.
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Affiliation(s)
- Gaurav Chaudhary
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Ashesh Ghosh
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Jin Gu Kang
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Paul V Braun
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Randy H Ewoldt
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
| | - Kenneth S Schweizer
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Department of Chemical & Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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18
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Liu W, Zhu Y, Zhang T, Zhu H, He C, Ngai T. Microrheology of thermoresponsive poly(N-isopropylacrylamide) microgel dispersions near a substrate surface. J Colloid Interface Sci 2021; 597:104-113. [PMID: 33866206 DOI: 10.1016/j.jcis.2021.03.181] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/30/2021] [Accepted: 03/31/2021] [Indexed: 10/21/2022]
Abstract
HYPOTHESIS Relative to the bulk systems, the near-wall (<500 nm) rheological responses of soft poly(N-isopropylacrylamide) (PNIPAM) microgel dispersions may exhibit distinct dependence on the frequency (ω), temperature (T), and effective volume fraction (ϕeff) during the volume phase transitions. The microrheological behaviors are expected to be governed by the near-wall microstructure and its spatial heterogeneity. EXPERIMENTS The combination of active microrheometry (multipole magnetic tweezers) and total internal reflection microscopy (TIRM) was employed to probe the structure-rheology relationships of microgel dispersions near a substrate surface. The ω, T, and ϕeff-dependences of the storage modulus (G'), loss modulus (G"), and softness (J) were analyzed by power-law and Arrhenius-like scaling theories. The fluctuation of J was further analyzed to give a quantitative description of the inhomogeneity in the near-wall regions. FINDINGS (1) Remarkable differences in the rheological behaviors between the bulk and near-wall cases are revealed, where the latter shows a segmented overlap behavior in ϕeff; (2) Five regimes of ϕeff that correspond to distinct physical states of the microgel dispersions are determined; (3) The near-wall local structures exhibit more heterogeneity in the glass and colloidal gel regimes as compared to the liquid regime.
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Affiliation(s)
- Wei Liu
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China; Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China; College of Food Engineering and Biotechnology, Hanshan Normal University, Chaozhou 521041, China; Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
| | - Yuwei Zhu
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
| | - Tong Zhang
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
| | - Hui Zhu
- College of Food Engineering and Biotechnology, Hanshan Normal University, Chaozhou 521041, China
| | - Chuanxin He
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China.
| | - To Ngai
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
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19
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Najafi M, Habibi M, Fokkink R, Hennink WE, Vermonden T. LCST polymers with UCST behavior. SOFT MATTER 2021; 17:2132-2141. [PMID: 33439188 DOI: 10.1039/d0sm01505a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
In this study, temperature dependent behavior of dense dispersions of core crosslinked flower-like micelles is investigated. Micelles were prepared by mixing aqueous solutions of two ABA block copolymers with PEG B-blocks and thermosensitive A-blocks containing PNIPAM and crosslinkable moieties. At a temperature above the lower critical solution temperature (LCST), self-assembly of the polymers resulted in the formation of flower-like micelles with a hydrophilic PEG shell and a hydrophobic core. The micellar core was stabilized by native chemical ligation (NCL). Above the LCST, micelles displayed a radius of ∼35 nm, while a radius of ∼48 nm was found below the LCST due to hydration of the PNIPAM core. Concentrated dispersions of these micelles (≥7.5 wt%) showed glassy state behavior below a critical temperature (Tc: 28 °C) which is close to the LCST of the polymers. Below this Tc, the increase in the micelle volume resulted in compression of micelles together above a certain concentration and formation of a glass. We quantified and compared micelle packing at different concentrations and temperatures. The storage moduli (G') of the dispersions showed a universal dependence on the effective volume fraction, which increased substantially above a certain effective volume fraction of φ = 1.2. Furthermore, a disordered lattice model describing this behavior fitted the experimental data and revealed a critical volume fraction of φc = 1.31 close to the experimental value of φ = 1.2. The findings reported provide insights for the molecular design of novel thermosensitive PNIPAM nanoparticles with tunable structural and mechanical properties.
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Affiliation(s)
- Marzieh Najafi
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Science for Life, Faculty of Science, Utrecht University, P. O. Box 80082, 3508 TB Utrecht, The Netherlands.
| | - Mehdi Habibi
- Physics and Physical Chemistry of Foods, Wageningen University & Research, 6708 WG Wageningen, Wageningen, The Netherlands
| | - Remco Fokkink
- Physical Chemistry and Soft Matter, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Wim E Hennink
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Science for Life, Faculty of Science, Utrecht University, P. O. Box 80082, 3508 TB Utrecht, The Netherlands.
| | - Tina Vermonden
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Science for Life, Faculty of Science, Utrecht University, P. O. Box 80082, 3508 TB Utrecht, The Netherlands.
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20
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Nishizawa Y, Minato H, Inui T, Uchihashi T, Suzuki D. Nanostructures, Thermoresponsiveness, and Assembly Mechanism of Hydrogel Microspheres during Aqueous Free-Radical Precipitation Polymerization. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:151-159. [PMID: 33355463 DOI: 10.1021/acs.langmuir.0c02654] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Although techniques to produce uniformly sized hydrogel microspheres (microgels) by aqueous free-radical precipitation polymerization are well established, the details of the polymerization process remain mysterious. In the present study, the structural evolution and thermoresponsiveness of the developing microgels during the polymerization were evaluated by temperature-controlled high-speed atomic force microscopy. This analysis clarified that the swelling properties of the precursor microgels formed in the early stages of the polymerization are quite low due to the high incorporation of cross-linkers and that non-thermoresponsive deca-nanosized spherical domains are already present in the precursor microgels. Furthermore, we succeeded in tracking the formation of nuclei and their growth process, which has never been fully understood, in aqueous solution by real-time observations. These findings will help us to design functional microgels with the desired nanostructures via precipitation polymerization.
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Affiliation(s)
- Yuichiro Nishizawa
- Graduate School of Textile Science & Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan
| | - Haruka Minato
- Graduate School of Textile Science & Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan
| | - Takumi Inui
- Graduate School of Textile Science & Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan
| | - Takayuki Uchihashi
- Department of Physics and Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chiksusa-ku, Nagoya, Aichi 464-8602, Japan
- Exploratory Research Center on Life and Living Systems, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
| | - Daisuke Suzuki
- Graduate School of Textile Science & Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan
- Research Initiative for Supra-Materials, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan
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21
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Synthesis of erucic amide propyl betaine compound fracturing fluid system. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2020.125098] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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22
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Scheffold F. Pathways and challenges towards a complete characterization of microgels. Nat Commun 2020; 11:4315. [PMID: 32887886 PMCID: PMC7473851 DOI: 10.1038/s41467-020-17774-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 07/20/2020] [Indexed: 01/07/2023] Open
Abstract
Due to their controlled size, sensitivity to external stimuli, and ease-of-use, microgel colloids are unique building blocks for soft materials made by crosslinking polymers on the micrometer scale. Despite the plethora of work published, many questions about their internal structure, interactions, and phase behavior are still open. The reasons for this lack of understanding are the challenges arising from the small size of the microgel particles, complex pairwise interactions, and their solvent permeability. Here we describe pathways toward a complete understanding of microgel colloids based on recent experimental advances in nanoscale characterization, such as super-resolution microscopy, scattering methods, and modeling.
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Affiliation(s)
- Frank Scheffold
- Department of Physics, University of Fribourg, Chemin du Musée 3, 1700, Fribourg, Switzerland.
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23
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Minato H, Nishizawa Y, Uchihashi T, Suzuki D. Thermoresponsive structural changes of single poly(N-isopropyl acrylamide) hydrogel microspheres under densely packed conditions on a solid substrate. Polym J 2020. [DOI: 10.1038/s41428-020-0372-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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24
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Roullet M, Clegg PS, Frith WJ. Rheology of protein-stabilised emulsion gels envisioned as composite networks 1- Comparison of pure droplet gels and protein gels. J Colloid Interface Sci 2020; 579:878-887. [PMID: 32679385 DOI: 10.1016/j.jcis.2020.05.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 04/30/2020] [Accepted: 05/01/2020] [Indexed: 01/08/2023]
Abstract
HYPOTHESIS Protein-stabilised emulsion gels can be studied in the theoretical framework of colloidal gels, because both protein assemblies and droplets may be considered as soft colloids. These particles differ in their nature, size and softness, and these differences may have an influence on the rheological properties of the gels they form. EXPERIMENTS Pure gels made of milk proteins (sodium caseinate), or of sub-micron protein-stabilised droplets, were prepared by slow acidification of suspensions at various concentrations. Their microstructure was characterised, their viscoelasticity, both in the linear and non-linear regime, and their frequency dependence were measured, and the behaviour of the two types of gels was compared. FINDINGS Protein gels and droplet gels were found to have broadly similar microstructure and rheological properties when compared at fixed volume fraction, a parameter derived from the study of the viscosity of the suspensions formed by proteins and by droplets. The viscoelasticity displayed a power law behaviour in concentration, as did the storage modulus in frequency. Additionally, strain hardening was found to occur at low concentration. These behaviours differed slightly between protein gels and droplet gels, showing that some specific properties of the primary colloidal particles play a role in the development of the rheological properties of the gels.
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Affiliation(s)
- Marion Roullet
- Unilever R&D Colworth, Sharnbrook, Bedford MK44 1LQ, UK; School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, UK.
| | - Paul S Clegg
- School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, UK.
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25
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Frenzel L, Lokteva I, Koof M, Narayanan S, Grübel G, Lehmkühler F. Influence of TMAO as co-solvent on the gelation of silica-PNIPAm core-shell nanogels at intermediate volume fractions. Chemphyschem 2020; 21:1318-1325. [PMID: 32250508 PMCID: PMC7318175 DOI: 10.1002/cphc.202000114] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/20/2020] [Indexed: 12/29/2022]
Abstract
We study the structure and dynamics of poly(N-isopropylacrylamide) (PNIPAm) core-shell nanogels dispersed in aqueous trimethylamine N-oxide (TMAO) solutions by means of small-angle X-ray scattering and X-ray photon correlation spectroscopy (XPCS). Upon increasing the temperature above the lower critical solution temperature of PNIPAm at 33 °C, a colloidal gel is formed as identified by an increase of I(q) at small q as well as a slowing down of sample dynamics by various orders of magnitude. With increasing TMAO concentration the gelation transition shifts linearly to lower temperatures. Above a TMAO concentration of approximately 0.40 mol/L corresponding to a 1 : 1 ratio of TMAO and NIPAm groups, collapsed PNIPAm states are found for all temperatures without any gelation transition. This suggests that reduction of PNIPAm-water hydrogen bonds due to the presence of TMAO results in a stabilisation of the collapsed PNIPAm state and suppresses gelation of the nanogel.
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Affiliation(s)
- Lara Frenzel
- Deutsches Elektronen-Synchrotron DESYNotkestr. 8522607HamburgGermany
- The Hamburg Centre for Ultrafast ImagingLuruper Chaussee 14922761HamburgGermany
| | - Irina Lokteva
- Deutsches Elektronen-Synchrotron DESYNotkestr. 8522607HamburgGermany
- The Hamburg Centre for Ultrafast ImagingLuruper Chaussee 14922761HamburgGermany
| | - Michael Koof
- Deutsches Elektronen-Synchrotron DESYNotkestr. 8522607HamburgGermany
- The Hamburg Centre for Ultrafast ImagingLuruper Chaussee 14922761HamburgGermany
| | - Suresh Narayanan
- Advanced Photon SourceArgonne National LaboratoryArgonneIllinois60439United States
| | - Gerhard Grübel
- Deutsches Elektronen-Synchrotron DESYNotkestr. 8522607HamburgGermany
- The Hamburg Centre for Ultrafast ImagingLuruper Chaussee 14922761HamburgGermany
| | - Felix Lehmkühler
- Deutsches Elektronen-Synchrotron DESYNotkestr. 8522607HamburgGermany
- The Hamburg Centre for Ultrafast ImagingLuruper Chaussee 14922761HamburgGermany
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26
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Minami S, Yamamoto A, Oura S, Watanabe T, Suzuki D, Urayama K. Criteria for colloidal gelation of thermo-sensitive poly(N-isopropylacrylamide) based microgels. J Colloid Interface Sci 2020; 568:165-175. [DOI: 10.1016/j.jcis.2020.02.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 02/12/2020] [Accepted: 02/13/2020] [Indexed: 11/24/2022]
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27
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Legrand A, Craig GA, Bonneau M, Minami S, Urayama K, Furukawa S. Understanding the multiscale self-assembly of metal-organic polyhedra towards functionally graded porous gels. Chem Sci 2019; 10:10833-10842. [PMID: 32110353 PMCID: PMC7012067 DOI: 10.1039/c9sc04543k] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 10/31/2019] [Indexed: 12/19/2022] Open
Abstract
Spatial heterogeneity and gradients within porous materials are key for controlling their mechanical properties and mass/energy transport, both in biological and synthetic materials. However, it is still challenging to induce such complexity in well-defined microporous materials such as crystalline metal-organic frameworks (MOFs). Here we show a method to generate a continuous gradient of porosity over multiple length scales by taking advantage of the amorphous nature of supramolecular polymers based on metal-organic polyhedra (MOPs). First, we use time-resolved dynamic light scattering (TRDLS) to elucidate the mechanism of hierarchical self-assembly of MOPs into colloidal gels and to understand the relationship between the MOP concentrations and the architecture of the resulting colloidal networks. These features directly impact the viscoelastic response of the gels and their mechanical strength. We then show that gradients of stiffness and porosity can be created within the gel by applying centrifugal force at the point of colloidal aggregation. These results with the creation of asymmetric and graded pore configuration in soft materials could lead to the emergence of advanced properties that are coupled to asymmetric molecule/ion transport as seen in biological systems.
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Affiliation(s)
- Alexandre Legrand
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS) , Kyoto University , Yoshida, Sakyo-ku , Kyoto 606-8501 , Japan .
| | - Gavin A Craig
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS) , Kyoto University , Yoshida, Sakyo-ku , Kyoto 606-8501 , Japan .
| | - Mickaele Bonneau
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS) , Kyoto University , Yoshida, Sakyo-ku , Kyoto 606-8501 , Japan .
| | - Saori Minami
- Department of Macromolecular Science and Engineering , Kyoto Institute of Technology , Matsugasaki, Sakyo-ku , Kyoto 606-8585 , Japan
| | - Kenji Urayama
- Department of Macromolecular Science and Engineering , Kyoto Institute of Technology , Matsugasaki, Sakyo-ku , Kyoto 606-8585 , Japan
| | - Shuhei Furukawa
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS) , Kyoto University , Yoshida, Sakyo-ku , Kyoto 606-8501 , Japan .
- Department of Synthetic Chemistry and Biological Chemistry , Graduate School of Engineering , Kyoto University , Katsura, Nishikyo-ku , Kyoto 615-8510 , Japan
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28
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Feng Y, Koos E. Editorial overview: Rheology of soft materials: Recent progresses. Curr Opin Colloid Interface Sci 2019. [DOI: 10.1016/j.cocis.2019.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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