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Kumar B, Noor N, Thakur S, Pan N, Narayana H, Yan SC, Wang F, Shah P. Shape Memory Polyurethane-Based Smart Polymer Substrates for Physiologically Responsive, Dynamic Pressure (Re)Distribution. ACS OMEGA 2019; 4:15348-15358. [PMID: 31572833 PMCID: PMC6761750 DOI: 10.1021/acsomega.9b01167] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 09/02/2019] [Indexed: 06/10/2023]
Abstract
Shape memory polymers (SMPs) are an exciting class of stimuli-responsive smart materials that demonstrate reactive and reversible changes in mechanical property, usually by switching between different states due to external stimuli. We report on the development of a polyurethane-based SMP foam for effective pressure redistribution that demonstrates controllable changes in dynamic pressure redistribution capability at a low transition temperature (∼24 °C)-ideally suited to matching modulations in body contact pressure for dynamic pressure relief (e.g., for alleviation or pressure ulcer effects). The resultant SMP material has been extensively characterized by a series of tests including stress-strain testing, compression testing, dynamic mechanical analysis, optical microscopy, UV-visible absorbance spectroscopy, variable-temperature areal pressure distribution, Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, differential scanning calorimetry, dynamic thermogravimetric analysis, and 1H nuclear magnetic resonance spectroscopy. The foam system exhibits high responsivity when tested for plantar pressure modulation with significant potential in pressure ulcers treatment. Efficient pressure redistribution (∼80% reduction in interface pressure), high stress response (∼30% applied stress is stored in fixity and released on recovery), and excellent deformation recovery (∼100%) are demonstrated in addition to significant cycling ability without performance loss. By providing highly effective pressure redistribution and modulation when in contact with the body's surface, this SMP foam offers novel mechanisms for alleviating the risk of pressure ulcers.
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Affiliation(s)
- Bipin Kumar
- Department of Textile Technology, Indian
Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Nuruzzaman Noor
- Institute of Textiles and Clothing, University Research
Facility in Chemical and Environmental Analysis, and School of Design, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Suman Thakur
- Institute of Textiles and Clothing, University Research
Facility in Chemical and Environmental Analysis, and School of Design, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Ning Pan
- Biological & Agricultural Engineering, UC Davis, Davis, California 95616, United States
| | - Harishkumar Narayana
- Institute of Textiles and Clothing, University Research
Facility in Chemical and Environmental Analysis, and School of Design, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Siu-cheong Yan
- Institute of Textiles and Clothing, University Research
Facility in Chemical and Environmental Analysis, and School of Design, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Faming Wang
- Institute of Textiles and Clothing, University Research
Facility in Chemical and Environmental Analysis, and School of Design, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Parth Shah
- Institute of Textiles and Clothing, University Research
Facility in Chemical and Environmental Analysis, and School of Design, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
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Zhang T, Sanguramath RA, Israel S, Silverstein MS. Emulsion Templating: Porous Polymers and Beyond. Macromolecules 2019. [DOI: 10.1021/acs.macromol.8b02576] [Citation(s) in RCA: 178] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Tao Zhang
- Department of Materials Science and Engineering, Technion−Israel Institute of Technology, Haifa 32000, Israel
- College of Textile and Clothing Engineering, Soochow University, Suzhou 215123, China
| | | | - Sima Israel
- Department of Materials Science and Engineering, Technion−Israel Institute of Technology, Haifa 32000, Israel
| | - Michael S. Silverstein
- Department of Materials Science and Engineering, Technion−Israel Institute of Technology, Haifa 32000, Israel
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Mouquet A, Khidas Y, Saison T, Faou JY, Pitois O. Well-controlled foam-based solid coatings. SOFT MATTER 2019; 15:5084-5093. [PMID: 31184688 DOI: 10.1039/c9sm00786e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Foam-based solid coatings appear to be a simple solution for giving new properties to solid surfaces. An efficient method is presented for producing open-cell foam coatings having a tunable pore radius distribution (i.e. monodisperse within the range 100-1000 μm, bidisperse or fully polydisperse), tunable thickness, and tunable bulk and surface porosities. This is achieved by mixing a precursor aqueous foam and particle suspension (here a micrometer-sized polyurethane dispersion), and by spreading with a nozzle the resulting particle-loaded foam on the solid surface to be coated. It is shown that the bubble size distribution of the precursor foam can be preserved in the final solid coating. This is highlighted by using a monodisperse aqueous foam, for which coatings showed a polycrystalline structure, as well as bidisperse or fully polydisperse foams. As a major advantage of our method, the bubble size and solid volume fraction are shown to be independent parameters, allowing the size of the microstructural elements to be tuned easily, and so the expected functional properties of the coating. Results obtained with the studied polyurethane dispersion are expected to be reproduced with other dispersions.
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Affiliation(s)
- A Mouquet
- Université Paris Est, Laboratoire Navier, UMR 8205 CNRS -École des Ponts ParisTech - IFSTTAR cité Descartes, 2 allée Kepler, 77420 Champs-sur-Marne, France.
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Wang F, Altschuh P, Ratke L, Zhang H, Selzer M, Nestler B. Progress Report on Phase Separation in Polymer Solutions. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1806733. [PMID: 30856293 DOI: 10.1002/adma.201806733] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 11/22/2018] [Indexed: 05/11/2023]
Abstract
Polymeric porous media (PPM) are widely used as advanced materials, such as sound dampening foams, lithium-ion batteries, stretchable sensors, and biofilters. The functionality, reliability, and durability of these materials have a strong dependence on the microstructural patterns of PPM. One underlying mechanism for the formation of porosity in PPM is phase separation, which engenders polymer-rich and polymer-poor (pore) phases. Herein, the phase separation in polymer solutions is discussed from two different aspects: diffusion and hydrodynamic effects. For phase separation governed by diffusion, two novel morphological transitions are reviewed: "cluster-to-percolation" and "percolation-to-droplets," which are attributed to an effect that the polymer-rich and the solvent-rich phases reach the equilibrium states asynchronously. In the case dictated by hydrodynamics, a deterministic nature for the microstructural evolution during phase separation is scrutinized. The deterministic nature is caused by an interfacial-tension-gradient (solutal Marangoni force), which can lead to directional movement of droplets as well as hydrodynamic instabilities during phase separation.
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Affiliation(s)
- Fei Wang
- Institute of Applied Materials-Computational Materials Science, Karlsruhe Institute of Technology (KIT), Straße am Forum 7, 76131, Karlsruhe, Germany
| | - Patrick Altschuh
- Institute of Applied Materials-Computational Materials Science, Karlsruhe Institute of Technology (KIT), Straße am Forum 7, 76131, Karlsruhe, Germany
- Institute of Digital Materials Science, Karlsruhe University of Applied Sciences, Moltkestraße 30, 76133, Karlsruhe, Germany
| | - Lorenz Ratke
- Institute of Materials Research, German Aerospace Center (DLR), Linder Hoehe, 51147, Cologne, Germany
| | - Haodong Zhang
- Institute of Applied Materials-Computational Materials Science, Karlsruhe Institute of Technology (KIT), Straße am Forum 7, 76131, Karlsruhe, Germany
| | - Michael Selzer
- Institute of Applied Materials-Computational Materials Science, Karlsruhe Institute of Technology (KIT), Straße am Forum 7, 76131, Karlsruhe, Germany
- Institute of Digital Materials Science, Karlsruhe University of Applied Sciences, Moltkestraße 30, 76133, Karlsruhe, Germany
| | - Britta Nestler
- Institute of Applied Materials-Computational Materials Science, Karlsruhe Institute of Technology (KIT), Straße am Forum 7, 76131, Karlsruhe, Germany
- Institute of Digital Materials Science, Karlsruhe University of Applied Sciences, Moltkestraße 30, 76133, Karlsruhe, Germany
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Bae J, Lee J, Zhou Q, Kim T. Micro-/Nanofluidics for Liquid-Mediated Patterning of Hybrid-Scale Material Structures. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1804953. [PMID: 30600554 DOI: 10.1002/adma.201804953] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 09/17/2018] [Indexed: 06/09/2023]
Abstract
Various materials are fabricated to form specific structures/patterns at the micro-/nanoscale, which exhibit additional functions and performance. Recent liquid-mediated fabrication methods utilizing bottom-up approaches benefit from micro-/nanofluidic technologies that provide a high controllability for manipulating fluids containing various solutes, suspensions, and building blocks at the microscale and/or nanoscale. Here, the state-of-the-art micro-/nanofluidic approaches are discussed, which facilitate the liquid-mediated patterning of various hybrid-scale material structures, thereby showing many additional advantages in cost, labor, resolution, and throughput. Such systems are categorized here according to three representative forms defined by the degree of the free-fluid-fluid interface: free, semiconfined, and fully confined forms. The micro-/nanofluidic methods for each form are discussed, followed by recent examples of their applications. To close, the remaining issues and potential applications are summarized.
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Affiliation(s)
- Juyeol Bae
- Department of Mechanical Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan, 44919, Republic of Korea
| | - Jongwan Lee
- Department of Mechanical Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan, 44919, Republic of Korea
| | - Qitao Zhou
- Department of Mechanical Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan, 44919, Republic of Korea
| | - Taesung Kim
- Department of Mechanical Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan, 44919, Republic of Korea
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Tu S, Zhao Y, Tan H, Yu H, Zhu X, Wang H. Ultralight Silica Foams with a Hierarchical Pore Structure via a Surfactant-Free High Internal Phase Emulsion Process. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:10381-10388. [PMID: 30088939 DOI: 10.1021/acs.langmuir.8b02094] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
An ultralight silica aerogel is among the most versatile materials available for technical applications; however, it remains a huge challenge to reduce its manufacturing cost. Here, we report on a simple approach for the preparation of silica foam monoliths with ultrahigh porosity up to 99.5% and specific surface area as high as 755 m2 g-1, which are similar to those of an aerogel. Our strategy is based on the effective stabilization of water-in-oil high internal phase emulsions by a hydrophobic silica precursor polymer, hyperbranched polyethoxysiloxane because of its hydrolysis-induced amphiphilicity. After conversion of this precursor polymer to silica, the emulsions are solidified without significant volume shrinkage. Thus, mechanically strong macroporous silica monoliths are obtained after removal of its liquid components. According to nitrogen sorption data, the resulting silica foams exhibit a high specific surface area and a foam skeleton consisting of both micropores (<2 nm) and mesopores (2-50 nm). The pore size, porosity, and surface area can be regulated by varying pH as well as the concentration of the silica precursor in the oil phase. In addition, the pore size can be adjusted by controlling shear force during emulsification. This work opens a new avenue for producing ultralight porous materials amenable to numerous applications.
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Affiliation(s)
- Shuhua Tu
- State Key Laboratory of Molecular Engineering of Polymers, Collaborative Innovation Center of Polymers and Polymer Composite Materials, Department of Macromolecular Science , Fudan University , Shanghai 200433 , China
| | - Yongliang Zhao
- Shanghai Dilato Materials Co., Ltd , Shanghai 200433 , China
| | - Haotian Tan
- State Key Laboratory of Molecular Engineering of Polymers, Collaborative Innovation Center of Polymers and Polymer Composite Materials, Department of Macromolecular Science , Fudan University , Shanghai 200433 , China
| | - Heng Yu
- State Key Laboratory of Molecular Engineering of Polymers, Collaborative Innovation Center of Polymers and Polymer Composite Materials, Department of Macromolecular Science , Fudan University , Shanghai 200433 , China
| | - Xiaomin Zhu
- DWI-Leibniz-Institute for Interactive Materials e.V. and Institute for Technical and Macromolecular Chemistry of RWTH Aachen University , Aachen 52056 , Germany
| | - Haitao Wang
- State Key Laboratory of Molecular Engineering of Polymers, Collaborative Innovation Center of Polymers and Polymer Composite Materials, Department of Macromolecular Science , Fudan University , Shanghai 200433 , China
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