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Blagojevic N, Müller M. Simulation of Membrane Fabrication via Solvent Evaporation and Nonsolvent-Induced Phase Separation. ACS APPLIED MATERIALS & INTERFACES 2023; 15:57913-57927. [PMID: 37222486 PMCID: PMC10739593 DOI: 10.1021/acsami.3c03126] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 05/08/2023] [Indexed: 05/25/2023]
Abstract
Block copolymer membranes offer a bottom-up approach to form isoporous membranes that are useful for ultrafiltration of functional macromolecules, colloids, and water purification. The fabrication of isoporous block copolymer membranes from a mixed film of an asymmetric block copolymer and two solvents involves two stages: First, the volatile solvent evaporates, creating a polymer skin, in which the block copolymer self-assembles into a top layer, comprised of perpendicularly oriented cylinders, via evaporation-induced self-assembly (EISA). This top layer imparts selectivity onto the membrane. Subsequently, the film is brought into contact with a nonsolvent, and the exchange between the remaining nonvolatile solvent and nonsolvent through the self-assembled top layer results in nonsolvent-induced phase separation (NIPS). Thereby, a macroporous support for the functional top layer that imparts mechanical stability onto the system without significantly affecting permeability is fabricated. We use a single, particle-based simulation technique to investigate the sequence of both processes, EISA and NIPS. The simulations identify a process window, which allows for the successful in silico fabrication of integral-asymmetric, isoporous diblock copolymer membranes, and provide direct insights into the spatiotemporal structure formation and arrest. The role of the different thermodynamic (e.g., solvent selectivity for the block copolymer components) and kinetic (e.g., plasticizing effect of the solvent) characteristics is discussed.
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Affiliation(s)
- Niklas Blagojevic
- Institute for Theoretical
Physics, Georg-August University of Göttingen, 37077 Göttingen, Germany
| | - Marcus Müller
- Institute for Theoretical
Physics, Georg-August University of Göttingen, 37077 Göttingen, Germany
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Garcia JU, Tree DR, Bagoyo A, Iwama T, Delaney KT, Fredrickson GH. Coarsening dynamics of ternary polymer solutions with mobility and viscosity contrasts. J Chem Phys 2023; 159:214904. [PMID: 38054518 DOI: 10.1063/5.0173992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Accepted: 11/14/2023] [Indexed: 12/07/2023] Open
Abstract
Using phase-field simulations, we investigate the bulk coarsening dynamics of ternary polymer solutions undergoing a glass transition for two models of phase separation: diffusion only and with hydrodynamics. The glass transition is incorporated in both models by imposing mobility and viscosity contrasts between the polymer-rich and polymer-poor phases of the evolving microstructure. For microstructures composed of polymer-poor clusters in a polymer-rich matrix, the mobility and viscosity contrasts significantly hinder coarsening, effectively leading to structural arrest. For microstructures composed of polymer-rich clusters in a polymer-poor matrix, the mobility and viscosity contrasts do not impede domain growth; rather, they change the transient concentration of the polymer-rich phase, altering the shape of the discrete domains. This effect introduces several complexities to the coarsening process, including percolation inversion of the polymer-rich and polymer-poor phases-a phenomenon normally attributed to viscoelastic phase separation.
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Affiliation(s)
- Jan Ulric Garcia
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA
- Asahi Kasei Corporation, 2-1 Samejima, Fuji, Shizuoka 416-8501, Japan
| | - Douglas R Tree
- Department of Chemical Engineering, Brigham Young University, Provo, Utah 84602, USA
| | - Alyssa Bagoyo
- Department of Chemical Engineering, Brigham Young University, Provo, Utah 84602, USA
| | - Tatsuhiro Iwama
- Asahi Kasei Corporation, 2-1 Samejima, Fuji, Shizuoka 416-8501, Japan
| | - Kris T Delaney
- Materials Research Laboratory, University of California, Santa Barbara, California 93106, USA
| | - Glenn H Fredrickson
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA
- Materials Research Laboratory, University of California, Santa Barbara, California 93106, USA
- Department of Materials, University of California, Santa Barbara, California 93106, USA
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Wang JH, Xue CH, Liu BY, Guo XJ, Hu LC, Wang HD, Deng FQ. A Superhydrophobic Dual-Mode Film for Energy-Free Radiative Cooling and Solar Heating. ACS OMEGA 2022; 7:15247-15257. [PMID: 35572754 PMCID: PMC9089744 DOI: 10.1021/acsomega.2c01947] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 04/07/2022] [Indexed: 06/15/2023]
Abstract
Traditional electric cooling in summer and coal heating in winter consume a huge amount of energy and lead to a greenhouse effect. Herein, we developed an energy-free dual-mode superhydrophobic film, which consists of a white side with porous coating of styrene-ethylene-butylene-styrene/SiO2 for radiative cooling and a black side with nanocomposite coating of carbon nanotubes/polydimethylsiloxane for solar heating. In the cooling mode with the white side, the film achieved a high sunlight reflection of 94% and a strong long-wave infrared emission of 92% in the range of 8-13 μm to contribute to a temperature drop of ∼11 °C. In the heating mode with the black side, the film achieved a high solar absorption of 98% to induce heating to raise the air temperature beneath by ΔT of ∼35.6 °C. Importantly, both sides of the film are superhydrophobic with a contact angle over 165° and a sliding angle near 0°, showing typical self-cleaning effects, which defend the surfaces from outdoor contamination, thus conducive to long-term cooling and heating. This dual-mode film shows great potential in outdoor applications as coverings for both cooling in hot summer and heating in winter without an energy input.
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Affiliation(s)
- Jiang-He Wang
- College
of Chemistry and Chemical Engineering, Shaanxi
University of Science and Technology, Xi’an 710021, China
| | - Chao-Hua Xue
- College
of Chemistry and Chemical Engineering, Shaanxi
University of Science and Technology, Xi’an 710021, China
- College
of Bioresources Chemical and Materials Engineering, Shaanxi University of Science and Technology, Xi’an 710021, China
| | - Bing-Ying Liu
- College
of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi’an 710021, China
| | - Xiao-Jing Guo
- College
of Materials Science and Engineering, Shaanxi
University of Science and Technology, Xi’an 710021, China
| | - Li-Cui Hu
- College
of Bioresources Chemical and Materials Engineering, Shaanxi University of Science and Technology, Xi’an 710021, China
| | - Hui-Di Wang
- College
of Materials Science and Engineering, Shaanxi
University of Science and Technology, Xi’an 710021, China
| | - Fu-Quan Deng
- College
of Bioresources Chemical and Materials Engineering, Shaanxi University of Science and Technology, Xi’an 710021, China
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Müller M, Abetz V. Nonequilibrium Processes in Polymer Membrane Formation: Theory and Experiment. Chem Rev 2021; 121:14189-14231. [PMID: 34032399 DOI: 10.1021/acs.chemrev.1c00029] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Porous polymer and copolymer membranes are useful for ultrafiltration of functional macromolecules, colloids, and water purification. In particular, block copolymer membranes offer a bottom-up approach to form isoporous membranes. To optimize permeability, selectivity, longevity, and cost, and to rationally design fabrication processes, direct insights into the spatiotemporal structure evolution are necessary. Because of a multitude of nonequilibrium processes in polymer membrane formation, theoretical predictions via continuum models and particle simulations remain a challenge. We compiled experimental observations and theoretical approaches for homo- and block copolymer membranes prepared by nonsolvent-induced phase separation and highlight the interplay of multiple nonequilibrium processes─evaporation, solvent-nonsolvent exchange, diffusion, hydrodynamic flow, viscoelasticity, macro- and microphase separation, and dynamic arrest─that dictates the complex structure of the membrane on different scales.
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Affiliation(s)
- Marcus Müller
- Georg-August Universität, Institut für Theoretische Physik, 37073 Göttingen, Germany
| | - Volker Abetz
- Helmholtz-Zentrum Hereon, Institut für Membranforschung, 21502 Geesthacht, Germany.,Universität Hamburg, Institut für Physikalische Chemie, 20146 Hamburg, Germany
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Liao C, Wang X. Triphasic Polymer Particles Assembled via Microphase Separation with Multiple Functions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:11818-11834. [PMID: 34585922 DOI: 10.1021/acs.langmuir.1c01769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
This work investigated a unique type of triphasic colloidal particles composed of an azo polymer (PCNAZO), a fluorescent pyrene-containing polymer [P(MMA-co-PyMA)], and a poly(dimethylsiloxane)-based polymer (H2pdca-PDMS), focusing on the synthesis, forming mechanism, morphology control, and functions. The triphasic particles with well-defined morphologies were assembled through the microphase separation of the components in dichloromethane (DCM) droplets in an aqueous medium, induced by the gradual evaporation of the organic solvent. The real-time fluorescence emission spectra of the pyrenyl moieties and in situ microscopic observations show that the formation of the triphasic particles undergoes the segregation of the PCNAZO-rich phase, separation between P(MMA-co-PyMA)-rich and H2pdca-PDMS-rich phases, coalescence, and solidification in the dispersed droplets. The structure formation is due to the strong phase separation of the polymers as revealed by the calculations based on the Flory-Huggins theory. The morphologies and phase boundaries of the particles are found to be controlled by the interfacial energy between the phases and processing conditions. The triphasic particles thus obtained possess a series of interesting functions stemming from the polymers and the triple-compartmentalized structures. After being deposited on a substrate, the H2pdca-PDMS parts can tightly adhere on the surface, caused by the spreading nature of the polymer when slightly swelled by DCM. Upon irradiation with a linearly polarized laser beam at 488 nm, the azo polymer compartments show a significant elongation along the electric vibration direction of the polarized light, accompanied by the cooperative deformation of the H2pdca-PDMS pads. When dispersed in water and adhered on the substrate surface, the triphasic particles exhibit tunable colors originating from the fluorescence of the pyrenyl fluorophores and light absorption of the azo chromophores. The real-time investigation methods developed here could lead to the deep understanding of the structure formation process in the confined volume and be applied in phase-separation study of other polymers as well.
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Affiliation(s)
- Chuyi Liao
- Department of Chemical Engineering, Laboratory of Advanced Materials (MOE), Tsinghua University, Beijing 100084, P. R. China
| | - Xiaogong Wang
- Department of Chemical Engineering, Laboratory of Advanced Materials (MOE), Tsinghua University, Beijing 100084, P. R. China
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