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Mei H, Mahalik JP, Lee D, Laws TS, Terlier T, Stein GE, Kumar R, Verduzco R. Understanding interfacial segregation in polymer blend films with random and mixed side chain bottlebrush copolymer additives. SOFT MATTER 2021; 17:9028-9039. [PMID: 34523659 DOI: 10.1039/d1sm01146d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Bottlebrush polymers are complex macromolecules with tunable physical properties dependent on the chemistry and architecture of both the side chains and the backbone. Prior work has demonstrated that bottlebrush polymer additives can be used to control the interfacial properties of blends with linear polymers but has not specifically addressed the effects of bottlebrush side chain microstructures. Here, using a combination of experiments and self-consistent field theory (SCFT) simulations, we investigated the effects of side chain microstructures by comparing the segregation of bottlebrush additives having random copolymer side chains with bottlebrush additives having a mixture of two different homopolymer side chain chemistries. Specifically, we synthesized bottlebrush polymers with either poly(styrene-ran-methyl methacrylate) side chains or with a mixture of polystyrene (PS) and poly(methyl methacrylate) (PMMA) side chains. The bottlebrush additives were matched in terms of PS and PMMA compositions, and they were blended with linear PS or PMMA chains that ranged in length from shorter to longer than the bottlebrush side chains. Experiments revealed similar behaviors of the two types of bottlebrushes, with a slight preference for mixed side-chain bottlebrushes at the film surface. SCFT simulations were qualitatively consistent with experimental observations, predicting only slight differences in the segregation of bottlebrush additives driven by side chain microstructures. Specifically, these slight differences were driven by the chemistries of the bottlebrush polymer joints and side chain end-groups, which were entropically repelled and attracted to interfaces, respectively. Using SCFT, we also demonstrated that the interfacial behaviors were dominated by entropic effects with high molecular weight linear polymers, leading to enrichment of bottlebrush near interfaces. Surprisingly, the SCFT simulations showed that the chemistry of the joints connecting the bottlebrush backbones and side chains played a more significant role compared with the side chain end groups in affecting differences in surface excess of bottlebrushes with random and mixed side chains. This work provides new insights into the effects of side chain microstructure on segregation of bottlebrush polymer additives.
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Affiliation(s)
- Hao Mei
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX 77005, USA.
| | - Jyoti P Mahalik
- Department of Polymer Science and Engineering, University of Massachusetts, Amherst, MA 01003, USA
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA.
| | - Dongjoo Lee
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX 77005, USA.
| | - Travis S Laws
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA
| | - Tanguy Terlier
- SIMS Lab, Shared Equipment Authority, Rice University, Houston, TX 77005, USA
| | - Gila E Stein
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA
| | - Rajeev Kumar
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA.
| | - Rafael Verduzco
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX 77005, USA.
- Materials Science and NanoEngineering, Rice University, Houston, TX 77005, USA
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Kalogirou A, Gergidis LN, Moultos O, Vlahos C. Entropic effects, shape, and size of mixed micelles formed by copolymers with complex architectures. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:052601. [PMID: 26651715 DOI: 10.1103/physreve.92.052601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Indexed: 06/05/2023]
Abstract
The entropic effects in the comicellization behavior of amphiphilic AB copolymers differing in the chain size of solvophilic A parts were studied by means of molecular dynamics simulations. In particular, mixtures of miktoarm star copolymers differing in the molecular weight of solvophilic arms were investigated. We found that the critical micelle concentration values show a positive deviation from the analytical predictions of the molecular theory of comicellization for chemically identical copolymers. This can be attributed to the effective interactions between copolymers originated from the arm size asymmetry. The effective interactions induce a very small decrease in the aggregation number of preferential micelles triggering the nonrandom mixing between the solvophilic moieties in the corona. Additionally, in order to specify how the chain architecture affects the size distribution and the shape of mixed micelles we studied star-shaped, H-shaped, and homo-linked-rings-linear mixtures. In the first case the individual constituents form micelles with preferential and wide aggregation numbers and in the latter case the individual constituents form wormlike and spherical micelles.
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Affiliation(s)
- Andreas Kalogirou
- Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece
| | - Leonidas N Gergidis
- Department of Materials Science & Engineering, University of Ioannina, 45110 Ioannina, Greece
| | - Othonas Moultos
- Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece
- Chemical Engineering Program, Texas A&M University at Qatar, P.O. Box 23874, Doha, Qatar
| | - Costas Vlahos
- Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece
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Qian Z, Minnikanti VS, Sauer BB, Dee GT, Kampert WG, Archer LA. Surface tension of polystyrene blends: Theory and experiment. ACTA ACUST UNITED AC 2009. [DOI: 10.1002/polb.21771] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Liu R, De Leonardis P, Cellesi F, Tirelli N, Saunders BR. Cationic temperature-responsive poly(N-isopropyl acrylamide) graft copolymers: from triggered association to gelation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:7099-7106. [PMID: 18547094 DOI: 10.1021/la8002756] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In this work temperature-triggered association and gel formation within aqueous solutions of a new family of cationic poly( N-isopropyl acrylamide) (PNIPAm) graft copolymers have been investigated. Five copolymers were synthesized using aqueous atom transfer radical polymerization (ATRP) involving a macroinitiator based on quaternarized N, N-dimethylaminoethyl methacrylate units (DMA+). The PDMA+) x - g-(PNIPAmn)y copolymers have x and y values that originate from the macroinitiator; values for n correspond to the PNIPAm arm length. The copolymer solutions exhibited temperature-triggered formation of nanometer-sized aggregates at the cloud point temperature, which was 33-34 degrees C. The aggregates were investigated using variable-temperature turbidity, hydrodynamic diameter, and electrophoretic mobility measurements. The aggregates were clearly evident using SEM and flowerlike or spherical morphologies were observed. Variable-temperature electrophoretic mobility measurements revealed that the zeta potentials of the aggregates increased with DMA+ content. A study of the effect of added NaNO3 showed that electrostatic interactions controlled the size of the aggregates. The concentrated graft copolymer solutions showed temperature-triggered gelation when the copolymer concentrations exceeded 5 wt %, Fluid-to-gel phase diagrams were constructed. It was found that electrostatic interactions also controlled the gelation temperature. A correlation was found between aggregate size and the minimum copolymer concentration needed to form a gel. A mechanism for the temperature-triggered structural changes leading to the formation of aggregates (in dilute solution) or gels (in concentrated solutions) is proposed.
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Affiliation(s)
- R Liu
- Polymer Science and Technology Group, The School of Materials, The University of Manchester, Grosvenor Street, M1 7HS, UK
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Reaction-induced microphase separation in thermosetting blends of epoxy resin with poly(methyl methacrylate)-block-polystyrene block copolymers: Effect of topologies of block copolymers on morphological structures. POLYMER 2008. [DOI: 10.1016/j.polymer.2008.05.010] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Theodorakis PE, Avgeropoulos A, Freire JJ, Kosmas M, Vlahos C. Effective interaction parameter of linear/star polymer blends and comparison with that of linear/linear and star/star blends. J Chem Phys 2007; 126:174904. [PMID: 17492883 DOI: 10.1063/1.2731786] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The authors present a detailed study of the microscopic parameters, which control the miscibility in binary linear/star polymer blends. The effective interactions of linear/star polymer blends are studied by means of Monte Carlo simulations and comparison is made with linear/linear and star/star blends, which they also determined. Using the bond fluctuation model on a simple cubic lattice, the authors are able to simulate symmetric linear/linear, star/star, and, for the first time, linear/star blends with a moderate number of arms. The simulations were performed at a volume fraction of occupied lattice sites phi=0.5, which corresponds to dense polymer mixtures for this algorithm. In particular, we study star/star blends with 4, 8, and 12 arms and the respective linear/linear blends as well as linear/star blends, all having the same total number of units equal to 73 and 121. The authors find that linear/star blends are more miscible than the corresponding linear/linear blends, which is in agreement with recent experimental and theoretical results. They find that linear/star mixtures are less miscible than star/star blends, a result which is also verified by theoretical findings.
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Affiliation(s)
- P E Theodorakis
- Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina, Greece
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Zhang H, Kulkarni S, Wunder SL. Blends of POSS−PEO(n=4)8 and High Molecular Weight Poly(ethylene oxide) as Solid Polymer Electrolytes for Lithium Batteries. J Phys Chem B 2007; 111:3583-90. [PMID: 17388529 DOI: 10.1021/jp064585g] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Solid polymer electrolyte blends were prepared with POSS-PEO(n=4)8 (3K), poly(ethylene oxide) (PEO(600K)), and LiClO4 at different salt concentrations (O/Li = 8/1, 12/1, and 16/1). POSS-PEO(n=4)8/LiClO4 is amorphous at all O/Li investigated, whereas PEO(600K) is amorphous only for O/Li = 8/1 and semicrystalline for O/Li = 12/1 and 16/1. The tendency of PEO(600K) to crystallize limited the amount of POSS-PEO(n=4)(8) that could be incorporated into the blends, so that the greatest incorporation of POSS-PEO(n=4)(8) occurred for O/Li = 8/1. Blends of POSS-PEO(n=4)(8)/PEO(600K)/LiClO4 (O/Li = 8/1 and 12/1) microphase separated into two amorphous phases, a low T(g) phase of composition 85% POSS-PEO(n=4)(8)/15% PEO(600K) and a high T(g) phase of composition 29% POSS-PEO(n=4)(8)/71% PEO(600K). For O/Li = 16/1, the blends contained crystalline (pure PEO(600K)), and two amorphous phases, one rich in POSS-PEO(n=4)(8) and one rich in PEO(600K). Microphase, rather than macrophase separation was believed to occur as a result of Li(+)/ether oxygen cross-link sites. The conductivity of the blends depended on their composition. As expected, crystallinity decreased the conductivity of the blends. For the amorphous blends, when the low T(g) (80/20) phase was the continuous phase, the conductivity was intermediate between that of pure PEO(600K) and POSS-PEO(n=4)(8). When the high T(g) (70/30, 50/50, 30/70, and 20/80) phase was the continuous phase, the conductivity of the blend and PEO(600K) were identical, and lower than that for the POSS-PEO(n=4)(8) over the whole temperature range (10-90 degrees C). This suggests that the motions of the POSS-PEO(n=4)(8) were slowed down by the dynamics of the long chain PEO(600K) and that the minor, low Tg phase was not interconnected and thus did not contribute to enhanced conductivity. At temperatures above T(m) of PEO(600K), addition of the POSS-PEO(n=4)(8) did not result in conductivity improvement. The highest RT conductivity, 8 x 10(-6) S/cm, was obtained for a 60% POSS-PEO(n=4)(8)/40% PEO(600K)/LiClO4 (O/Li = 12/1) blend.
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Affiliation(s)
- Hanjun Zhang
- Department of Chemistry 016-11, Temple University, Philadelphia, Pennsylvania 19122, USA
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Fan W, Zheng S. Miscibility and crystallization behavior in blends of poly(methyl methacrylate) and poly(vinylidene fluoride): Effect of star-like topology of poly(methyl methacrylate) chain. ACTA ACUST UNITED AC 2007. [DOI: 10.1002/polb.21264] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Shen J, Zheng S. Comparative studies on miscibility and phase behavior of linear and star poly(2-methyl-2-oxazoline) blends with poly(vinylidene fluoride). ACTA ACUST UNITED AC 2006. [DOI: 10.1002/polb.20748] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Huang CF, Kuo SW, Lin HC, Chen JK, Chen YK, Xu H, Chang FC. Thermal properties, miscibility and specific interactions in comparison of linear and star poly(methyl methacrylate) blend with phenolic. POLYMER 2004. [DOI: 10.1016/j.polymer.2004.05.043] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Synthesis of 4-, 8-, 12-arm star-branched polybutadienes with three different chain-end functionalities using a functionalized initiator. POLYMER 2004. [DOI: 10.1016/j.polymer.2003.11.047] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Martter TD, Foster MD, Ohno K, Haddleton DM. Architecture-driven thermodynamic interactions in blends of star-branched and linear poly(methyl methacrylate). ACTA ACUST UNITED AC 2002. [DOI: 10.1002/polb.10226] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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