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Singh J, Gupta S, Chokshi P. Confinement-induced self-assembly of a diblock copolymer within a non-uniform cylindrical nanopore. SOFT MATTER 2024; 20:1543-1553. [PMID: 38268494 DOI: 10.1039/d3sm01348k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2024]
Abstract
The self-assembly of a diblock copolymer melt confined within a non-uniform cylindrical nanopore is studied using the self-consistent field theory. The non-uniformity manifests in the form of a converging-diverging cylindrical nanopore. The axial variation in pore diameter presents a range of curvatures within the same confinement pore as opposed to a single curvature in a uniform-diameter cylindrical pore. The introduction of multiple curvatures leads to the formation of novel microstructures not accessible in uniform cylindrical confinement. The well-known equilibrium structures like a single helix, double helices, and concentric lamella under cylindrical confinement transition into new morphologies such as hyperboloidal phases, microstructures containing rings with a bead, rings with spheres, and a squeezed helical phase as the pore diameter varies axially. The converging-diverging geometry of the confining pore renders the helical phases seen in the cylindrical pore less favorable. A phase diagram in the parametric space of the block fraction and the ratio of the smallest and largest pore radii has been constructed to depict the order-order transition of various microstructures. The ratio of radii, a measure of the non-uniformity of the pore, along with the pore length brings out some interesting morphologies. The mechanism of these structural transitions is understood as the interplay between the variation in pore curvature attributed to the non-uniformity, the spontaneous curvature of the block copolymer interface, and the enthalpic interaction between the segregated blocks.
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Affiliation(s)
- Jagat Singh
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi 110 016, India.
| | - Supriya Gupta
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi 110 016, India.
| | - Paresh Chokshi
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi 110 016, India.
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2
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Zhang H, Pan F, Li S. Self-Assembly of Lipid Molecules under Shear Flows: A Dissipative Particle Dynamics Simulation Study. Biomolecules 2023; 13:1359. [PMID: 37759759 PMCID: PMC10526246 DOI: 10.3390/biom13091359] [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: 07/20/2023] [Revised: 08/28/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023] Open
Abstract
The self-assembly of lipid molecules in aqueous solution under shear flows was investigated using the dissipative particle dynamics simulation method. Three cases were considered: zero shear flow, weak shear flow and strong shear flow. Various self-assembled structures, such as double layers, perforated double layers, hierarchical discs, micelles, and vesicles, were observed. The self-assembly behavior was investigated in equilibrium by constructing phase diagrams based on chain lengths. Results showed the remarkable influence of chain length, shear flow and solution concentration on the self-assembly process. Furthermore, the self-assembly behavior of lipid molecules was analyzed using the system energy, particle number and shape factor during the dynamic processes, where the self-assembly pathways were observed and analyzed for the typical structures. The results enhance our understanding of biomacromolecule self-assembly in a solution and hold the potential for applications in biomedicine.
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Affiliation(s)
- Huan Zhang
- Department of Physics, Wenzhou University, Wenzhou 325035, China
| | - Fan Pan
- School of Data Science and Artificial Intelligence, Wenzhou University of Technology, Wenzhou 325035, China
| | - Shiben Li
- Department of Physics, Wenzhou University, Wenzhou 325035, China
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3
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Gupta S, Chokshi P. Self-organization of a 4-miktoarm star block copolymer induced by cylindrical confinement. SOFT MATTER 2021; 17:4929-4941. [PMID: 33725050 DOI: 10.1039/d1sm00149c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Self-consistent field calculations have been carried out to reveal the self-assembly behavior of a melt of the ABCD star tetrablock copolymer confined within a cylindrical nanopore. The miktoarm star block copolymer exhibits a rich self-assembly behavior with a myriad of interesting three-dimensional ordered phases with the potential to produce advanced nanomaterials. The broad array of ordered mesophases includes helical microstructures, stack of rings/doughnuts, honeycomb structure, and perforated lamella with beads, depending on the individual block fractions and the size of the cylindrical nanopore. Such chiral motifs generated from achiral polymeric molecules are fascinating due to their superior performance in sophisticated opto-electronic devices. The study also demonstrates an interesting morphology, viz. a honeycomb structure, obtained from the self-organization of ABCD star block copolymer molecules with equal block fractions. The system exhibits order-order phase transition covering a range of ordered morphologies by changing either the block fraction or the nanopore radius. A representative phase diagram in terms of block fractions is constructed. These novel ordered microstructures, arising mainly out of structural frustration and confinement-induced entropy loss, can serve as structural scaffolds to host the spatial distribution of nanoparticles resulting into novel nanocomposites with significantly enhanced as well as controllable properties.
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Affiliation(s)
- Supriya Gupta
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi 110 016, India.
| | - Paresh Chokshi
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi 110 016, India.
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Hu X, Wang Z, Yin Y, Jiang R, Li B. Controlling the chirality and number of strands of helices self-assembled from achiral block copolymers confined inside a nanopore: a simulation study. SOFT MATTER 2021; 17:4434-4444. [PMID: 33908596 DOI: 10.1039/d1sm00103e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Achiral block copolymers can self-assemble into helical structures when confined inside a cylindrical nanopore. However, controlling the chirality and the number of strands of helices is challenging. We present our simulation results of the influence of a chiral patch added to the confining nanopore on the structures and chirality of helices self-assembled from achiral cylinder-forming diblock copolymers under the confinement. Our results indicate that, when the designed patch is of proper geometry, it can induce the formation of helical structures and exhibit good control over their chirality. The bottom surface of the patch can induce the formation of a characteristic local structure near and parallel to it. It is the characteristic local structure that directs the formation of helices and of their chirality consistent with that of the patch. A large patch angle or the top/bottom surface of a weakly selective pore promotes the formation of double-helices compared to single-helices by enlarging the pitch of the helices near the patch or through the entropic attraction of the top surface of the pore to the minority blocks.
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Affiliation(s)
- Xiejun Hu
- School of Physics, Key Laboratory of Functional Polymer Materials of Ministry of Education, and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin, 300071, China.
| | - Zheng Wang
- School of Physics, Key Laboratory of Functional Polymer Materials of Ministry of Education, and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin, 300071, China.
| | - Yuhua Yin
- School of Physics, Key Laboratory of Functional Polymer Materials of Ministry of Education, and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin, 300071, China.
| | - Run Jiang
- School of Physics, Key Laboratory of Functional Polymer Materials of Ministry of Education, and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin, 300071, China.
| | - Baohui Li
- School of Physics, Key Laboratory of Functional Polymer Materials of Ministry of Education, and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin, 300071, China.
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Xie Q, Qiang Y, Zhang G, Li W. Emergence and Stability of Janus-Like Superstructures in an ABCA Linear Tetrablock Copolymer. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c01328] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Qiong Xie
- State Key Laboratory of Molecular Engineering of Polymers, Key Laboratory of Computational Physical Sciences, Department of Macromolecular Science, Fudan University, Shanghai 200433, China
| | - Yicheng Qiang
- State Key Laboratory of Molecular Engineering of Polymers, Key Laboratory of Computational Physical Sciences, Department of Macromolecular Science, Fudan University, Shanghai 200433, China
| | - Guojie Zhang
- Department of Chemical Engineering, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, China
| | - Weihua Li
- State Key Laboratory of Molecular Engineering of Polymers, Key Laboratory of Computational Physical Sciences, Department of Macromolecular Science, Fudan University, Shanghai 200433, China
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Gupta S, Chokshi P. Diblock copolymer templated self-assembly of grafted nanoparticles under circular pore confinement. SOFT MATTER 2020; 16:3522-3535. [PMID: 32215433 DOI: 10.1039/d0sm00124d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Geometrical confinement plays an important role in generating novel molecular organization arising out of structural frustration and confinement-induced entropy loss. In the present study, we perform self-consistent mean-field theoretical calculations to examine a mixture of a diblock copolymer and polymer grafted nanoparticles confined in a cylindrical nanopore. The two-dimensional analysis is aimed at constructing the equilibrium nanostructures decorated with particles in an ordered manner. The rich variety of ordered mesophases of the diblock copolymer under confinement provide a template to achieve the self-assembly of nanoparticles in a selective domain. The localization behavior of nanoparticles under confinement is found to be qualitatively different from that in a bulk system. In particular, for the concentric lamellar phase the particles tend to localize predominantly in the region of greater curvature within the curved lamella. The incorporation of grafted nanoparticles also results in a transition in ordered phases. Various equilibrium morphologies are observed depending upon the degree of confinement, particle loading, density of grafted segments and selectivity of the particle core to the polymeric species. The ordering of particles and the ensuing equilibrium nanostructures are analyzed. The comprehensive understanding of the self-assembly behavior of particles enables one to design novel nanomaterials with desirable material properties.
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Affiliation(s)
- Supriya Gupta
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi 110 016, India.
| | - Paresh Chokshi
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi 110 016, India.
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7
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Jiang Y, Qian M, Xu Y. Influence of Branches on the Phase Behavior of (AB) f Starlike Block Copolymer under Cylindrical Confinement. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:16813-16820. [PMID: 31789525 DOI: 10.1021/acs.langmuir.9b02740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Experimentally, self-assembled morphologies of the (AB)f starlike block copolymer are strongly dependent on the number of arms, f. For example, the 2- and 4-arm starlike block copolymers exhibited the morphologies of hexagonally arrayed polystyrene cylinder in the polyisoprene matrix while order-bicontinuous nanostructures were observed in 8-, 12-, and 18-arm stars. Theoretically, we found that the transition sequence for (AB)3 is C1B → DkB → P2B → L2B, which becomes C1B → L1B when f > 6. To explore the influence of f on the phase behavior of (AB)f under cylindrical confinement, we calculated the two-dimensional phase diagram with respect to the volume fraction and the pore diameter. Our conclusions show that the topologies of the phase diagram are independent of the number of arms; however, the number of arms does affect the phase boundary, which inevitably leads to the different phase transition sequences at fixed volume fraction. Therefore, from the calculated phase diagram, the influence of f on the phase behavior of the starlike copolymer is fully understood.
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Affiliation(s)
- Yangyang Jiang
- Faculty of Materials Science and Chemical Engineering , Ningbo University , 818 Fenghua Road , Ningbo , Zhejiang 315211 , China
| | - Mingshuang Qian
- Faculty of Materials Science and Chemical Engineering , Ningbo University , 818 Fenghua Road , Ningbo , Zhejiang 315211 , China
| | - Yuci Xu
- Faculty of Materials Science and Chemical Engineering , Ningbo University , 818 Fenghua Road , Ningbo , Zhejiang 315211 , China
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Shao Z, Zhang D, Hu W, Xu Y, Li W. Transition mechanisms of three-dimensional nanostructures formed from geometrically constraining (AB) star block copolymers. POLYMER 2019. [DOI: 10.1016/j.polymer.2019.05.062] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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9
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Zhou L, Peng J, Tan ZZ. Array-induced perfectly-ordered microstructures in nanoparticle-polymer mixtures. JOURNAL OF POLYMER RESEARCH 2019. [DOI: 10.1007/s10965-019-1828-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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10
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Jiang W, Qiang Y, Liu M, Li W, Qiu F, Shi AC. Tetragonal phase of cylinders self-assembled from binary blends of AB diblock and (A'B) n star copolymers. Phys Chem Chem Phys 2017; 19:25754-25763. [PMID: 28914309 DOI: 10.1039/c7cp03718j] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The phase behavior of binary blends composed of AB diblock and (A'B)n star copolymers is studied using the polymeric self-consistent field theory, focusing on the formation and stability of the stable tetragonal phase of cylinders. In general, cylindrical domains self-assembled from AB-type block copolymers are packed into a hexagonal array, although a tetragonal array of cylinders could be more favourable for lithography applications in microelectronics. The polymer blends are designed such that there is an attractive interaction between the A and A' blocks, which increases the compatibility between the two copolymers and thus suppresses the macroscopic phase separation of the blends. With an appropriate choice of system parameters, a considerable stability window for the targeted tetragonal phase is identified in the blends. Importantly, the transition mechanism between the hexagonal and tetragonal phases is elucidated by examining the distribution of the two types of copolymers in the unit cell of the structure. The results reveal that the short (A'B)n star copolymers are preferentially located in the bonding area connecting two neighboring domains in order to reduce extra stretching, whereas the long AB diblock copolymers are extended to further space of the unit cell.
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Affiliation(s)
- Wenbo Jiang
- 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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Wang C, Xu Y, Li W, Lin Z. Rich Variety of Three-Dimensional Nanostructures Enabled by Geometrically Constraining Star-like Block Copolymers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:7908-7916. [PMID: 27389278 DOI: 10.1021/acs.langmuir.6b01904] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The influence of star-like architecture on phase behavior of star-like block copolymer under cylindrical confinement differs largely from the bulk (i.e., nonconfinement). A set of intriguing self-assembled morphologies and the corresponding phase diagrams of star-like (AB)f diblock copolymers with different numbers of arms f (i.e., f = 3, 9, 15, and 21) in four scenarios (ϕA = 0.3 and V0 > 0; ϕA = 0.3 and V0 < 0; ϕA = 0.7 and V0 > 0; and ϕA = 0.7 and V0 < 0 (where ϕA is the volume fraction of A block) and V0 < 0 and V0 > 0 represent that the pore wall of cylindrical confinement prefers the inner A block (i.e., A-preferential) and B block (i.e., B-preferential), respectively) were for the first time scrutinized by employing the pseudospectral method of self-consistent mean-field theory. Surprisingly, a new nanoscopic phase, that is, perforated-lamellae-on-cylinder (denoted PC), was observed in star-like (AB)3 diblock copolymer at ϕA = 0.3 and V0 > 0. With a further increase in f, a single lamellae (denoted L1) was found to possess a larger phase region. Under the confinement of A-preferential wall (i.e., V0 < 0) at ϕA = 0.3, PC phase became metastable and its free energy increased as f increased. Quite intriguingly, when ϕA = 0.7 and V0 > 0, where an inverted cylinder was formed in bulk, the PC phase became stable, and its free energy decreased as f increased, suggesting the propensity to form PC phase under this condition. Moreover, in stark contrast to the phase transition of C1 → L1 → PC (C1, a single cylindrical microdmain) at ϕA = 0.3 and V0 > 0, when subjected to the A-preferential wall (ϕA = 0.7), a different phase transition sequence (i.e., C1 → PC → L1) was identified due to the formation of a double-layer structure. On the basis of our calculations, the influence of star-like architecture on (AB)f diblock copolymer under the imposed cylindrical confinement, particularly the shift of the phase boundaries as a function of f, was thoroughly understood. These self-assembled nanostructures may hold the promise for applications as lithographic templates for nanowires, photonic crystals, and nanotechnology.
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Affiliation(s)
- Chao Wang
- Faculty of Materials Science and Chemical Engineering, Ningbo University , Ningbo, Zhejiang 315211, China
| | - Yuci Xu
- Faculty of Materials Science and Chemical Engineering, Ningbo University , Ningbo, Zhejiang 315211, China
| | - Weihua Li
- State Key Laboratory of Molecular Engineering of Polymer, Department of Macromolecular Science, Fudan University , Shanghai 200433, China
| | - Zhiqun Lin
- School of Materials Science and Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
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12
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Self-assembly of tiling-forming ABC star triblock copolymers in cylindrical nanotubes: A study of self-consistent field theory. J Taiwan Inst Chem Eng 2016. [DOI: 10.1016/j.jtice.2016.05.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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13
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Morphologies and phase diagrams of ABC star triblock copolymers in cylindrical nanotubes with homogenous and patterned surfaces. POLYMER 2016. [DOI: 10.1016/j.polymer.2016.03.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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14
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Huang JH, Wu JJ, Huang XW. Self-assembly of symmetric rod-coil diblock copolymers in cylindrical nanopore. RSC Adv 2016. [DOI: 10.1039/c6ra22122j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Self-assembly of rod-coil (RC) symmetric diblock copolymers (DBCs) in a cylindrical nanopore is investigated by performing dissipative particle dynamics simulation.
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Affiliation(s)
- Jian-Hua Huang
- Department of Chemistry
- Zhejiang Sci-Tech University
- Hangzhou 310018
- China
| | - Jia-Jun Wu
- Department of Chemistry
- Zhejiang Sci-Tech University
- Hangzhou 310018
- China
| | - Xiao-Wei Huang
- Department of Chemistry
- Zhejiang Sci-Tech University
- Hangzhou 310018
- China
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15
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Zhang T, Deng H, Yang T, Li W. Defective morphologies kinetically formed in diblock copolymers under the cylindrical confinement. POLYMER 2015. [DOI: 10.1016/j.polymer.2015.03.059] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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16
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Xu Y, Wang C, Zhong S, Li W, Lin Z. Self-assembly of miktoarm star-like ABn block copolymers: from wet to dry brushes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:2905-2913. [PMID: 25689323 DOI: 10.1021/acs.langmuir.5b00081] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Self-assembly of miktoarm star-like ABn block copolymer in both selective solvent (A- or B-selective) and miscible homopolymer matrix (A or B homopolymer), that is, formation of micelles, was for the first time investigated by theoretical calculations based on self-consistent mean field theory. Interestingly, the calculation revealed that the size of micelles in solvent was smaller than that in homopolymer under the same conditions. In B-selective solvent, with increasing number of B blocks n in miktoarm star-like ABn block copolymer at a fixed volume fraction of A block, the micellar size decreased gradually. In stark contrast, when miktoarm star-like ABn block copolymer dissolved in B homopolymer matrix at molecular weight ratio of B homopolymer to ABn block copolymer fH = 0.30, the overall micellar size decreased nonmonotonically as the number of B blocks n in ABn block copolymer increased. The largest micelle was formed in AB2 (i.e., n = 2). This intriguing finding can be attributed to a wet-to-dry brush transition that occurred from n = 1 to n = 2 in the micellization of miktoarm star-like ABn block copolymer. Moreover, the micellization behaviors of miktoarm star-like ABn block copolymer in A-selective solvent and A homopolymer matrix were also explored, where the overall micellar size in both scenarios was found to decrease monotonically as n in ABn block copolymer increased. These self-assembled nanostructures composed of miktoarm star-like ABn block copolymers may promise a wide range of applications in size-dependent drug delivery and bionanotechnology.
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Affiliation(s)
- Yuci Xu
- Department of Polymer Science and Engineering, Faculty of Materials Science and Chemical Engineering, Key Laboratory of Specialty Polymers, Ningbo University , Ningbo, Zhejiang 315211, China
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Synthesis and self-assembly in bulk of star-shaped block copolymers based on helical polypeptides. Colloid Polym Sci 2014. [DOI: 10.1007/s00396-014-3345-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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18
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Ross CA, Berggren KK, Cheng JY, Jung YS, Chang JB. Three-dimensional nanofabrication by block copolymer self-assembly. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:4386-4396. [PMID: 24706521 DOI: 10.1002/adma.201400386] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 02/20/2014] [Indexed: 06/03/2023]
Abstract
Thin films of block copolymers are widely seen as enablers for nanoscale fabrication of semiconductor devices, membranes, and other structures, taking advantage of microphase separation to produce well-organized nanostructures with periods of a few nm and above. However, the inherently three-dimensional structure of block copolymer microdomains could enable them to make 3D devices and structures directly, which could lead to efficient fabrication of complex heterogeneous structures. This article reviews recent progress in developing 3D nanofabrication processes based on block copolymers.
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Affiliation(s)
- Caroline A Ross
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
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19
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Jiang WB, Lang WC, Li SB, Wang XH. Morphologies of Core-Shell-Cylinder-Forming ABC Star Triblock Copolymers in Nanopores. CHINESE J CHEM PHYS 2014. [DOI: 10.1063/1674-0068/27/03/337-342] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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20
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Xu Y, Li W, Qiu F, Lin Z. Self-assembly of 21-arm star-like diblock copolymer in bulk and under cylindrical confinement. NANOSCALE 2014; 6:6844-6852. [PMID: 24830862 DOI: 10.1039/c4nr01275e] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Phase behaviors of a 21-arm star-like diblock copolymer in bulk and under confinement were explored by using the pseudo-spectral method of a self-consistent mean field theory. An asymmetrical phase diagram in bulk was constructed by comparing the free energy of different structures. The gyroid phase was found to possess a large phase region when the inner block in the star-like diblock copolymer has a small volume fraction, suggesting the propensity to form the gyroid phase under this condition. Combined with the early experimental work, a scaling law correlating the period of lamellae D(multiarms) formed from multi-arm star-like block copolymers with the number of arms f was identified, that is, D(multiarms) = D/f(1/2), where D is the period of a linear diblock copolymer with the same degree of polymerization N as a star-like diblock copolymer. The scaling law was also substantiated by the scaling theory. The bridging fraction of the lamellae formed in a star-like diblock copolymer was nearly 100%, which is advantageous for improving its mechanical properties. Some interesting two-dimensional and three-dimensional morphologies were yielded under the cylindrical confinement, where a 3D double helix was found to be the most stable structure.
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Affiliation(s)
- Yuci Xu
- Department of Macromolecular Science and Engineering, Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, China
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21
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Zhang R, Zeng X, Prehm M, Liu F, Grimm S, Geuss M, Steinhart M, Tschierske C, Ungar G. Honeycombs in honeycombs: complex liquid crystal alumina composite mesostructures. ACS NANO 2014; 8:4500-4509. [PMID: 24758721 DOI: 10.1021/nn406368e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Small-angle X-ray scattering (SAXS) and atomic force microscopy (AFM) were used to study orientation patterns of two polyphilic liquid crystals (LC) confined to cylindrical pores of anodic aluminum oxide (AAO). The hierarchical hybrid systems had the LC honeycomb (lattice parameter 3.5-4 nm) inside the pores of the AAO honeycomb (diameters 60 and 400 nm). By conducting complete reciprocal space mapping using SAXS, we conclude that the columns of both compounds align in planes normal to the AAO pore axis, with a specific crystallographic direction of the LC lattice aligning strictly parallel to the pore axis. AFM of LC-containing AAO fracture surfaces further revealed that the columns of the planar anchoring LC (compound 1) formed concentric circles in the plane normal to the pore axis near the AAO wall. Toward the pore center, the circles become anisometric "racetrack" loops consisting of two straight segments and two semicircles. This mode compensates for slight ellipticity of the pore cross section. Indications are, however, that for perfectly circular pores, circular shape is maintained right to the center of the pore, the radius coming down to the size of a molecule. For the homeotropically anchoring compound 2, the columns are to the most part straight and parallel to each other, arranged in layers normal to the AAO pore axis, like logs in an ordered pile. Only near the pore wall the columns splay somewhat. In both cases, columns are confined to layers strictly perpendicular to the AAO pore axis, and there is no sign of escape to the third dimension or of axial orientation, the latter having been reported previously for some discotic LCs. The main cause of the two new LC configurations, the "racetrack" and the "logpile", and of their difference from those of confined nematic LC, is the very high splay energy and low bend energy of columnar phases.
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Affiliation(s)
- Ruibin Zhang
- Department of Materials Science and Engineering, University of Sheffield , Sheffield S1 3JD, United Kingdom
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22
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Liu M, Li W, Qiu F. Segmented helical structures formed by ABC star copolymers in nanopores. J Chem Phys 2013; 138:104904. [PMID: 23514516 DOI: 10.1063/1.4794785] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Self-assembly of ABC star triblock copolymers confined in cylindrical nanopores is studied using self-consistent mean-field theory. With an ABC terpolymer forming hexagonally-arranged cylinders, segmented into alternative B and C domains, in the bulk, we observe the formation in the nanopore of a segmented single circular and non-circular cylinder, a segmented single-helix, and a segmented double-helix as stable phases, and a metastable stacked-disk phase with fourfold symmetry. The phase sequence from single-cylinder, to single-helix, and then to double-helix, is similar as that in the cylindrically-confined diblock copolymers except for the absence of an equilibrium stacked-disk phase. It is revealed that the arrangement of the three-arm junctions plays a critical role for the structure formation. One of the most interesting features in the helical structures is that there are two periods: the period of the B/C domains in the helix and the helical period. We demonstrate that the period numbers of the B/C domains contained in each helical period can be tuned by varying the pore diameter. In addition, it is predicted that the period number of B/C domains can be any rational in real helical structures whose helical period can be tuned freely.
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Affiliation(s)
- Meijiao Liu
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433, China
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Xu Y, Xie N, Li W, Qiu F, Shi AC. Phase behaviors and ordering dynamics of diblock copolymer self-assembly directed by lateral hexagonal confinement. J Chem Phys 2012. [DOI: 10.1063/1.4765098] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Yuci Xu
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433, China
| | - Nan Xie
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433, China
| | - Weihua Li
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433, China
| | - Feng Qiu
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433, China
- Key Laboratory of Computational Physical Sciences, Ministry of Education of China, Shanghai 200433, China
| | - An-Chang Shi
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
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Li S, Qiu W, Zhang L, Liang H. Nanostructures and phase diagrams of ABC star triblock copolymers in pore geometries. J Chem Phys 2012; 136:124906. [DOI: 10.1063/1.3697764] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Xu Y, Li W, Qiu F, Zhang H, Yang Y, Shi AC. Stability of hierarchical lamellar morphologies formed in ABC star triblock copolymers. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/polb.22000] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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