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Singh AK, Chauhan A, Singh A. Growth kinetics and morphology characterization of binary polymeric fluid under random photo-illumination. J Chem Phys 2024; 160:024907. [PMID: 38193555 DOI: 10.1063/5.0181688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 12/18/2023] [Indexed: 01/10/2024] Open
Abstract
We present a comprehensive study using dissipative particle dynamics simulations to investigate phase separation kinetics (PSK) in three-dimensional (3d) polymeric fluids under random photo-illumination. We consider two scenarios: polymer blends with active radicals at one end of each immiscible chain and block copolymer (BCP) melts with photosensitive bonds linking incompatible blocks. The phase separation (PS) is induced by temperature quench of the initial homogeneously mixed system. Simultaneously, the system experiences random photo-illumination, simulated by two concurrent random events: (a) the recombination of active radicals in polymer blends and (b) the breaking of photosensitive bonds in BCP chains. Variations in the bond-breaking probability, Pb, mimic the change in light intensity. The length scale follows power law growth, R(t) ∼ tϕ, where ϕ represents the growth exponent. Increasing Pb results in a gradual transition in growth kinetics from micro-PS to macro-PS, accompanied by corresponding transition probabilities for both systems. Micro-PSK dominates the evolution process at low Pb values. The scaling functions exhibit data overlap for most scaled distances, indicating the statistical self-similarity of evolving patterns. Our study enhances the understanding of PSK in polymeric fluids, revealing the impact of photosensitive bonds and active radicals. Furthermore, it suggests the potential for designing novel polymeric materials with desired properties.
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Affiliation(s)
- Ashish Kumar Singh
- Department of Physics, Indian Institute of Technology (BHU), Varanasi, Uttar Pradesh 221005, India
| | - Avinash Chauhan
- Department of Physics, Indian Institute of Technology (BHU), Varanasi, Uttar Pradesh 221005, India
| | - Awaneesh Singh
- Department of Physics, Indian Institute of Technology (BHU), Varanasi, Uttar Pradesh 221005, India
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Singh AK, Chauhan A, Puri S, Singh A. Photo-induced bond breaking during phase separation kinetics of block copolymer melts: a dissipative particle dynamics study. SOFT MATTER 2021; 17:1802-1813. [PMID: 33399613 DOI: 10.1039/d0sm01664k] [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
Using a dissipative particle dynamics (DPD) simulation method, we study the phase separation dynamics in block copolymer (BCP) melts in d = 3, subjected to external stimuli such as light. An initial homogeneous BCP melt is rapidly quenched to a temperature T < Tc, where Tc is the critical temperature. We then allow the system to undergo alternate light "on" and "off" cycles. An on-cycle breaks the stimuli-sensitive bonds connecting both the blocks A and B in the BCP melt, and during the off-cycle, the broken bonds recombine. By simulating the effect of light, we isolate scenarios where phase separation begins with the light off (set 1); the cooperative interactions within the system allow it to undergo microphase separation. When the phase separation starts with the light on (set 2), the system undergoes macrophase separation due to bond breaking. Here, we report the role of alternate cycles on domain morphology by varying the bond-breaking probability for both set 1 and set 2, respectively. We observe that the scaling functions depend upon the conditions mentioned above that change the time scale of the evolving morphologies in various cycles. However, in all the cases, the average domain size respects the power-law growth: R(t) ∼tφ at late times, where φ is the dynamic growth exponent. After a short-lived diffusive growth (φ∼ 1/3) at early times, φ illustrates a crossover from the viscous hydrodynamic (φ∼ 1) to the inertial hydrodynamic (φ∼ 2/3) regimes at late times.
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Affiliation(s)
- Ashish Kumar Singh
- Department of Physics, Indian Institute of Technology (BHU), Varanasi-221005, India.
| | - Avinash Chauhan
- Department of Physics, Indian Institute of Technology (BHU), Varanasi-221005, India.
| | - Sanjay Puri
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi-110067, India.
| | - Awaneesh Singh
- Department of Physics, Indian Institute of Technology (BHU), Varanasi-221005, India.
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de Castro P, Sollich P. Phase separation of mixtures after a second quench: composition heterogeneities. SOFT MATTER 2019; 15:9287-9299. [PMID: 31637388 DOI: 10.1039/c9sm01706b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We investigate binary mixtures undergoing phase separation after a second (deeper) temperature quench into two- and three-phase coexistence regions. The analysis is based on a lattice theory previously developed for gas-liquid separation in generic mixtures. Our previous results, which considered an arbitrary number of species and a single quench, showed that, due to slow changes in composition, dense colloidal mixtures can phase-separate in two stages. Moreover, the denser phase contains long-lived composition heterogeneities that originate as the interfaces of shrunk domains. Here we predict several new effects that arise after a second quench, mostly associated with the extent to which crowding can slow down 'fractionation', i.e. equilibration of compositions. They include long-lived regular arrangements of secondary domains; wetting of fractionated interfaces by oppositely fractionated layers; 'surface'-directed spinodal 'waves' propagating from primary interfaces; a 'dead zone' where no phase separation occurs; and, in the case of three-phase coexistence, filamentous morphologies arising out of secondary domains.
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Affiliation(s)
- Pablo de Castro
- Disordered Systems Group, Department of Mathematics, King's College London, London, UK.
| | - Peter Sollich
- Disordered Systems Group, Department of Mathematics, King's College London, London, UK. and Institut für Theoretische Physik, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
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Saranathan V, Forster JD, Noh H, Liew SF, Mochrie SGJ, Cao H, Dufresne ER, Prum RO. Structure and optical function of amorphous photonic nanostructures from avian feather barbs: a comparative small angle X-ray scattering (SAXS) analysis of 230 bird species. J R Soc Interface 2012; 9:2563-80. [PMID: 22572026 DOI: 10.1098/rsif.2012.0191] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Non-iridescent structural colours of feathers are a diverse and an important part of the phenotype of many birds. These colours are generally produced by three-dimensional, amorphous (or quasi-ordered) spongy β-keratin and air nanostructures found in the medullary cells of feather barbs. Two main classes of three-dimensional barb nanostructures are known, characterized by a tortuous network of air channels or a close packing of spheroidal air cavities. Using synchrotron small angle X-ray scattering (SAXS) and optical spectrophotometry, we characterized the nanostructure and optical function of 297 distinctly coloured feathers from 230 species belonging to 163 genera in 51 avian families. The SAXS data provided quantitative diagnoses of the channel- and sphere-type nanostructures, and confirmed the presence of a predominant, isotropic length scale of variation in refractive index that produces strong reinforcement of a narrow band of scattered wavelengths. The SAXS structural data identified a new class of rudimentary or weakly nanostructured feathers responsible for slate-grey, and blue-grey structural colours. SAXS structural data provided good predictions of the single-scattering peak of the optical reflectance of the feathers. The SAXS structural measurements of channel- and sphere-type nanostructures are also similar to experimental scattering data from synthetic soft matter systems that self-assemble by phase separation. These results further support the hypothesis that colour-producing protein and air nanostructures in feather barbs are probably self-assembled by arrested phase separation of polymerizing β-keratin from the cytoplasm of medullary cells. Such avian amorphous photonic nanostructures with isotropic optical properties may provide biomimetic inspiration for photonic technology.
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Affiliation(s)
- Vinodkumar Saranathan
- Department of Ecology and Evolutionary Biology and Peabody Museum of Natural History, Yale University, New Haven, CT 06520, USA.
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Li YC, Shi RP, Wang CP, Liu XJ, Wang Y. Predicting microstructures in polymer blends under two-step quench in two-dimensional space. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 83:041502. [PMID: 21599164 DOI: 10.1103/physreve.83.041502] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2010] [Indexed: 05/30/2023]
Abstract
The formation of nanostructures during two-step quench in binary polymer systems having various types of liquid miscibility gaps are investigated systematically via computer simulations using the phase field method. Coupled liquid spinodal decomposition and fluid flow processes are considered by solving simultaneously the Cahn-Hilliard and Navier-Stokes equations. Various interesting phenomena and morphological patterns are predicted. It is found that the primary microstructures developed at the first quench and isothermal holding temperature greatly affect the secondary microstructures developed during the second quench and isothermal holding. Depending on the morphology and scale of the primary microstructure, either multicore and multishell or unicore and unishell structures are predicted. The breakup of annuluses in a core-shell structure in two dimensions is analyzed. The effects of viscosity on the formation of core-shell structure and on the growth and coarsening behaviors of bimodal droplets produced by the two-step quench in systems are also investigated.
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Affiliation(s)
- Y C Li
- Department of Materials Science and Engineering, College of Materials, and Research Center of Materials Design and Applications, Xiamen University, Xiamen 361005, People's Republic of China
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Yang J, Chen X, Fu R, Luo WA, Li Y, Zhang M. Kinetics of phase separation in polymer blends revealed by resonance light scattering spectroscopy. Phys Chem Chem Phys 2010; 12:2238-45. [DOI: 10.1039/b918069a] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Tang XL, Li L, Zhao L, Zhang HD, Wu PY. Using two-dimensional time resolved light scattering to study the cure reaction induced phase separation process of epoxy-amine-polyethersulfone blend with secondary phase separation. CHINESE JOURNAL OF POLYMER SCIENCE 2009. [DOI: 10.1007/s10118-010-8201-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Yan LT, Li J, Zhang F, Xie XM. Surface-Directed Phase Separation via a Two-Step Quench Process in Binary Polymer Mixture Films with Asymmetry Compositions. J Phys Chem B 2008; 112:8499-506. [DOI: 10.1021/jp801648t] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Li-Tang Yan
- Advanced Materials Laboratory, Department of Chemical Engineering, Tsinghua University, Beijing 100084, People’s Republic of China
| | - Jialin Li
- Advanced Materials Laboratory, Department of Chemical Engineering, Tsinghua University, Beijing 100084, People’s Republic of China
| | - Fengbo Zhang
- Advanced Materials Laboratory, Department of Chemical Engineering, Tsinghua University, Beijing 100084, People’s Republic of China
| | - Xu-Ming Xie
- Advanced Materials Laboratory, Department of Chemical Engineering, Tsinghua University, Beijing 100084, People’s Republic of China
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Yan LT, Li J, Xie XM. Three-dimensional numerical simulations of lamellar structure via two-step surface-directed phase separation in polymer blend films. J Chem Phys 2008; 128:224906. [DOI: 10.1063/1.2938370] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Yan LT, Xie XM. The phase dynamics and wetting layer formation mechanisms in two-step surface-directed spinodal decomposition. J Chem Phys 2008; 128:154702. [DOI: 10.1063/1.2897974] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Yan LT, Xie XM. Lamellar morphology induced by two-step surface-directed spinodal decomposition in binary polymer mixture films. J Chem Phys 2008; 128:034901. [DOI: 10.1063/1.2819676] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Sun Z, Song HH. Thermal Induced Periodic Phase Separation in Polymer Blends. CHINESE J CHEM PHYS 2006. [DOI: 10.1360/cjcp2006.19(2).99.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Sun Z, Song H. Pattern Evolution Induced by Periodic Temperature Modulation in a Binary Polymeric Mixture. MACROMOL THEOR SIMUL 2006. [DOI: 10.1002/mats.200500086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Buxton GA, Clarke N. Creating structures in polymer blends via a dissolution and phase-separation process. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2005; 72:011807. [PMID: 16089993 DOI: 10.1103/physreve.72.011807] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2005] [Indexed: 05/03/2023]
Abstract
We show how three-dimensional structures can be formed in polymer blends from pre-existing structures. "Tape" of one polymer is inserted into a matrix of an alternative polymer to form an array of parallelepipeds. We subject this regular structure to partial dissolution in the one-phase region, before quenching the system into the two-phase region. The interplay between dissolution and phase separation can result in complex hierarchic structures. In particular, arrays of microchannels of one polymer species can be formed inside the other polymer.
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Sigehuzi T, Tanaka H. Coarsening mechanism of phase separation caused by a double temperature quench in an off-symmetric binary mixture. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2004; 70:051504. [PMID: 15600621 DOI: 10.1103/physreve.70.051504] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2004] [Indexed: 05/24/2023]
Abstract
We study phase-separation behavior of an off-symmetric fluid mixture induced by a "double temperature quench." We first quench a system into the unstable region. After a large phase-separated structure is formed, we again quench the system more deeply and follow the pattern-evolution process. The second quench makes the domains formed by the first quench unstable and leads to double phase separation; that is, small droplets are formed inside the large domains created by the first quench. The complex coarsening behavior of this hierarchic structure having two characteristic length scales is studied in detail by using the digital image analysis. We find three distinct time regimes in the time evolution of the structure factor of the system. In the first regime, small droplets coarsen with time inside large domains. There a large domain containing small droplets in it can be regarded as an isolated system. Later, however, the coarsening of small droplets stops when they start to interact via diffusion with the large domain containing them. Finally, small droplets disappear due to the Lifshitz-Slyozov mechanism. Thus the observed behavior can be explained by the crossover of the nature of a large domain from the isolated to the open system; this is a direct consequence of the existence of the two characteristic length scales.
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Affiliation(s)
- Tomoo Sigehuzi
- Institute of Industrial Science, University of Tokyo, Meguro-ku, Tokyo 153-8505, Japan
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Abstract
The phase separation process in a critical mixture of polydimethylsiloxane and polyethylmethylsiloxane (PDMS/PEMS, a system with an upper critical solution temperature) was investigated by time-resolved light scattering during continuous quenches from the one-phase into the two-phase region. Continuous quenches were realized by cooling ramps with different cooling rates kappa. Phase separation kinetics is studied by means of the temporal evolution of the scattering vector qm and the intensity Im at the scattering peak. The curves qm(t) for different cooling rates can be shifted onto a single mastercurve. The curves Im(t) show similar behavior. As shift factors, a characteristic length Lc and a characteristic time tc are introduced. Both characteristic quantities depend on the cooling rate through power laws: Lc approximately kappa(-delta) and tc approximately kappa(-rho). Scaling behavior in isothermal critical demixing is well known. There the temporal evolutions of qm and Im for different quench depths DeltaT can be scaled with the correlation length xi and the interdiffusion coefficient D, both depending on DeltaT through critical power laws. We show in this paper that the cooling rate scaling in nonisothermal demixing is a consequence of the quench depth scaling in the isothermal case. The exponents delta and rho are related to the critical exponents nu and nu* of xi and D, respectively. The structure growth during nonisothermal demixing can be described with a semiempirical model based on the hydrodynamic coarsening mechanism well known in the isothermal case. In very late stages of nonisothermal phase separation a secondary scattering maximum appears. This is due to secondary demixing. We explain the onset of secondary demixing by a competition between interdiffusion and coarsening.
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Affiliation(s)
- Max Rüllmann
- Deutsches Kunststoff-Institut, Schlossgartenstrasse 6, D-64289 Darmstadt, Germany
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Affiliation(s)
- Ian C. Henderson
- Department of Chemistry, University Science Laboratories, South Road, Durham DH1 3LE, United Kingdom
| | - Nigel Clarke
- Department of Chemistry, University Science Laboratories, South Road, Durham DH1 3LE, United Kingdom
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Graca M, Wieczorek SA, Hołyst R. Memory Effects in Homopolymer Blends during Annealing. Macromolecules 2002. [DOI: 10.1021/ma0206467] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M. Graca
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - S. A. Wieczorek
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - R. Hołyst
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
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Fiałkowski M, Hołyst R. Quench–jump sequence in phase separation in polymer blends. J Chem Phys 2002. [DOI: 10.1063/1.1487375] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Hayashi M, Jinnai H, Hashimoto T. Validity of linear analysis in early-stage spinodal decomposition of a polymer mixture. J Chem Phys 2000. [DOI: 10.1063/1.1287272] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Hayashi M, Jinnai H, Hashimoto T. Two-step phase separation of a polymer mixture. II. Time evolution of structure factor. J Chem Phys 2000. [DOI: 10.1063/1.481321] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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