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Gustavsson L, Lv ZP, Cherian T, Seppälä W, Liljeström V, Peng B, Huotari S, Rannou P, Ikkala O. Heating-Induced Switching to Hierarchical Liquid Crystallinity Combining Colloidal and Molecular Order in Zwitterionic Molecules. ACS OMEGA 2023; 8:39345-39353. [PMID: 37901556 PMCID: PMC10601052 DOI: 10.1021/acsomega.3c04914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 09/27/2023] [Indexed: 10/31/2023]
Abstract
Hierarchical self-assemblies of soft matter involving triggerable or switchable structures at different length scales have been pursued toward multifunctional behaviors and complexity inspired by biological matter. They require several and balanced competing attractive and repulsive interactions, which provide a grand challenge in particular in the "bulk" state, i.e., in the absence of plasticizing solvents. Here, we disclose that zwitterionic bis-n-tetradecylphosphobetaine, as a model compound, shows a complex thermally switchable hierarchical self-assembly in the solvent-free state. It shows polymorphism and heating-induced reversible switching from low-temperature molecular-level assemblies to high-temperature hierarchical self-assemblies, unexpectedly combining colloidal and molecular self-assemblies, as inferred by synchrotron small-angle X-ray scattering (SAXS). The high-temperature phase sustains birefringent flow, indicating a new type of hierarchical thermotropic liquid crystallinity. The high-temperature colloidal-level SAXS reflections suggest indexation as a 2D oblique pattern and their well-defined layer separation in the perpendicular direction. We suggest that the colloidal self-assembled motifs are 2D nanoplatelets formed by the lateral packing of the molecules, where the molecular packing frustration between the tightly packed zwitterionic moieties and the coiled alkyl chains demanding more space limits the lateral platelet growth controlled by the alkyl stretching entropy. An indirect proof is provided by the addition of plasticizing ionic liquids, which relieve the ionic dense packings of zwitterions, thus allowing purely smectic liquid crystallinity without the colloidal level order. Thus, molecules with a simple chemical structure can lead to structural hierarchy and tunable complexity in the solvent-free state by balancing the competing long-range electrostatics and short-range nanosegregations.
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Affiliation(s)
- Lotta Gustavsson
- Department
of Applied Physics, Aalto University, Puumiehenkuja 2, FI-00076 Espoo, Finland
| | - Zhong-Peng Lv
- Department
of Applied Physics, Aalto University, Puumiehenkuja 2, FI-00076 Espoo, Finland
| | - Tomy Cherian
- Department
of Applied Physics, Aalto University, Puumiehenkuja 2, FI-00076 Espoo, Finland
| | - Wille Seppälä
- Department
of Applied Physics, Aalto University, Puumiehenkuja 2, FI-00076 Espoo, Finland
| | - Ville Liljeström
- Nanomicroscopy
Center, Aalto University, Puumiehenkuja 2, FI-00076 Espoo, Finland
| | - Bo Peng
- Department
of Applied Physics, Aalto University, Puumiehenkuja 2, FI-00076 Espoo, Finland
| | - Simo Huotari
- Department
of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Patrice Rannou
- Université
Grenoble Alpes, Université Savoie Mont-Blanc, CNRS, Grenoble
INP, LEPMI, 38000 Grenoble, France
| | - Olli Ikkala
- Department
of Applied Physics, Aalto University, Puumiehenkuja 2, FI-00076 Espoo, Finland
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2
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Xu S, Xu W, Zheng Y, Yu C, Wang B, Pan P. Structural Organizations of a Mesogen-Terminated Semicrystalline Polymer: Chain Termini Ordering between Polymer Crystal Lamellae. J Phys Chem Lett 2022; 13:11703-11709. [PMID: 36512490 DOI: 10.1021/acs.jpclett.2c03271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
In polymer crystallization, the chain end groups are generally excluded into the nanoscaled amorphous regions confined between crystal lamellae. Understanding the structural characteristic and evolution of interlamellar end groups is of great importance to control the macroscopic properties of polymers. However, the structural evolution of those confined end groups and related physical evidence remain unclear. Herein, we synthesized the end-functionalized poly(lactic acid)s with a self-assemblable mesogenic termini (4-hexyloxy-4'-cyanobiphenyl) and investigated the structural evolution of mesogenic termini between crystal lamellae. Intriguingly, the mesogenic termini can organize into an ordered layer structure between polymer crystal lamellae; such a process strongly depends upon the interlamellar spacing. A higher crystallization temperature (Tc) of the polymer allows for a larger interlamellar region, favoring the formation of an ordered mesogenic layer. However, a lower Tc results in a restricted interlamellar region, in which the end groups are strongly confined without sufficient mobility to undergo structural ordering. This study provides evidence for the structural ordering of chain termini confined between polymer crystal lamellae.
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Affiliation(s)
- Shanshan Xu
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang 310027, People's Republic of China
| | - Wenqing Xu
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang 310027, People's Republic of China
| | - Ying Zheng
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang 310027, People's Republic of China
- Institute of Zhejiang University─Quzhou, 99 Zheda Road, Quzhou, Zhejiang 324000, People's Republic of China
| | - Chengtao Yu
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang 310027, People's Republic of China
- Institute of Zhejiang University─Quzhou, 99 Zheda Road, Quzhou, Zhejiang 324000, People's Republic of China
| | - Bao Wang
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang 310027, People's Republic of China
- Institute of Zhejiang University─Quzhou, 99 Zheda Road, Quzhou, Zhejiang 324000, People's Republic of China
| | - Pengju Pan
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang 310027, People's Republic of China
- Institute of Zhejiang University─Quzhou, 99 Zheda Road, Quzhou, Zhejiang 324000, People's Republic of China
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Lind TK, Nilsson EJ, Wyler B, Scherer D, Skansberger T, Morin M, Kocherbitov V, Engblom J. Effects of ethylene oxide chain length on crystallization of polysorbate 80 and its related compounds. J Colloid Interface Sci 2021; 592:468-484. [PMID: 33711648 DOI: 10.1016/j.jcis.2021.01.065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 11/18/2020] [Accepted: 01/07/2021] [Indexed: 11/17/2022]
Abstract
As a result of the synthesis protocol polyoxyethylene sorbitan monooleate (polysorbate 80, PS80) is a highly complex mixture of compounds. PS80 was therefore separated into its main constituents, e.g. polyoxyethylene isosorbide esters and polyoxyethylene esters, as well as mono- di- and polyesters using preparative high-performance liquid chromatography. In this comprehensive study the individual components and their ethoxylation level were verified by matrix assisted laser desorption/ionization time-of-flight and their thermotropic behavior was analyzed using differential scanning calorimetry and X-ray diffraction. A distinct correlation was found between the average length of the ethylene oxide (EO) chains in the headgroup and the individual compounds' ability to crystallize. Importantly, a critical number of EO units required for crystallization of the headgroup was determined (6 EO units per chain or 24 per molecule). The investigation also revealed that the hydrocarbon tails only crystallize for polyoxyethylene sorbitan esters if saturated. PS80 is synthesized by reacting with approximately 20 mol of EO per mole of sorbitol, however, the number of EO units in the sorbitan ester in commercial PS80 products is higher than the expected 20 (5 EO units per chain). The complex behavior of all tested compounds revealed that if the amount of several of the linear by-products is reduced, the number of EO units in the chains will stay below the critical number and the product will not be able to crystallize by the EO chains.
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Affiliation(s)
- Tania K Lind
- Biomedical Sciences, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden; Biofilms - Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden
| | - Emelie J Nilsson
- Biomedical Sciences, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden; Biofilms - Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden.
| | | | | | - Tatyana Skansberger
- Biomedical Sciences, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden; Biofilms - Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden
| | - Maxim Morin
- Biomedical Sciences, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden; Biofilms - Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden
| | - Vitaly Kocherbitov
- Biomedical Sciences, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden; Biofilms - Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden
| | - Johan Engblom
- Biomedical Sciences, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden; Biofilms - Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden.
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Xu W, Li X, Zheng Y, Yuan W, Zhou J, Yu C, Bao Y, Shan G, Pan P. Hierarchical ordering and multilayer structure of poly(ε-caprolactone) end-functionalized by a liquid crystalline unit: role of polymer crystallization. Polym Chem 2021. [DOI: 10.1039/d1py00702e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This study elucidates the role of polymer crystallization in the structural organization of LC end-functionalized polymers and offers a potential method to tune the hierarchical structures of end-functionalized polymers.
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Affiliation(s)
- Wenqing Xu
- State Key Laboratory of Chemical Engineering
- College of Chemical and Biological Engineering
- Zhejiang University
- Hangzhou 310027
- China
| | - Xing Li
- State Key Laboratory of Chemical Engineering
- College of Chemical and Biological Engineering
- Zhejiang University
- Hangzhou 310027
- China
| | - Ying Zheng
- State Key Laboratory of Chemical Engineering
- College of Chemical and Biological Engineering
- Zhejiang University
- Hangzhou 310027
- China
| | - Wenhua Yuan
- State Key Laboratory of Chemical Engineering
- College of Chemical and Biological Engineering
- Zhejiang University
- Hangzhou 310027
- China
| | - Jian Zhou
- State Key Laboratory of Chemical Engineering
- College of Chemical and Biological Engineering
- Zhejiang University
- Hangzhou 310027
- China
| | - Chengtao Yu
- State Key Laboratory of Chemical Engineering
- College of Chemical and Biological Engineering
- Zhejiang University
- Hangzhou 310027
- China
| | - Yongzhong Bao
- State Key Laboratory of Chemical Engineering
- College of Chemical and Biological Engineering
- Zhejiang University
- Hangzhou 310027
- China
| | - Guorong Shan
- State Key Laboratory of Chemical Engineering
- College of Chemical and Biological Engineering
- Zhejiang University
- Hangzhou 310027
- China
| | - Pengju Pan
- State Key Laboratory of Chemical Engineering
- College of Chemical and Biological Engineering
- Zhejiang University
- Hangzhou 310027
- China
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5
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Doganci E, Davarci D. Synthesized and mesomorphic properties of cholesterol end-capped poly(ε-caprolactone) polymers. JOURNAL OF POLYMER RESEARCH 2019. [DOI: 10.1007/s10965-019-1826-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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6
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Wu Q, Lv C, Zhang Z, Li Y, Nie J, Xu J, Du B. Poly( N-isopropylacrylamide- co-1-vinyl-3-alkylimidazolium bromide) Microgels with Internal Nanophase-Separated Structures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:9203-9214. [PMID: 29999323 DOI: 10.1021/acs.langmuir.8b01575] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Microgels with internal nanophase-separated structures were fabricated by surfactant-free emulsion copolymerization of N-isopropylacrylamide (NIPAm) and ionic liquid comonomers, namely, 1-vinyl-3-alkylimidazolium bromide (VIM nBr) with various lengths n of long alkyl side chain, in an aqueous solution at 70 °C using N, N'-methylenebisacrylamide as the cross-linker. Combined techniques of transmission electron microscopy, dynamic and static light-scattering, differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), small-angle X-ray scattering (SAXS), and polarized optical microscopy were employed to systematically investigate the sizes, morphologies, and properties of the obtained microgels as well as the microstructures and phase transition of nanophases inside the microgels. The obtained P(NIPAm/VIM nBr) microgels are spherical with narrow size distributions, and the nanophases have a radius of about 8-12 nm and are randomly distributed inside the microgels. The cooperative competition of the hydrophilic quaternary vinylimidazole moieties and hydrophobic long alkyl side chains determines the thermal sensitive behavior of the P(NIPAm/VIM nBr) microgels. DSC and WAXD results reveal that the nanophases consist of the ordered alkyl side chains with a layered crystalline structure at low temperature, which exhibit a low melting temperature and a broad melting transition. SAXS results further show that the nanophases form a layered liquid crystalline structure at high temperature for the microgel suspensions and freeze-dried microgels.
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7
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Interplay of microphase separation, crystallization and liquid crystalline ordering in crystalline/liquid crystalline block copolymers. POLYMER 2017. [DOI: 10.1016/j.polymer.2017.09.071] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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8
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Tong ZZ, Xue JQ, Wang RY, Huang J, Xu JT, Fan ZQ. Hierarchical self-assembly, photo-responsive phase behavior and variable tensile property of azobenzene-containing ABA triblock copolymers. RSC Adv 2015. [DOI: 10.1039/c4ra12844c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A series of triblock copolymers with liquid crystalline (LC) poly{6-[4-(4-methoxyphenylazo)phenoxy]hexyl methacrylate} (PMMAZO) as the end blocks and rubbery poly(n-butyl acrylate) (PnBA) as the midblock were synthesized.
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Affiliation(s)
- Zai-Zai Tong
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization
- Department of Polymer Science & Engineering
- Zhejiang University
- Hangzhou 310027
- China
| | - Jin-Qiao Xue
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization
- Department of Polymer Science & Engineering
- Zhejiang University
- Hangzhou 310027
- China
| | - Rui-Yang Wang
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization
- Department of Polymer Science & Engineering
- Zhejiang University
- Hangzhou 310027
- China
| | - Jie Huang
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization
- Department of Polymer Science & Engineering
- Zhejiang University
- Hangzhou 310027
- China
| | - Jun-Ting Xu
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization
- Department of Polymer Science & Engineering
- Zhejiang University
- Hangzhou 310027
- China
| | - Zhi-Qiang Fan
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization
- Department of Polymer Science & Engineering
- Zhejiang University
- Hangzhou 310027
- China
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9
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Deshmukh P, Ahn SK, Geelhand de Merxem L, Kasi RM. Interplay between Liquid Crystalline Order and Microphase Segregation on the Self-Assembly of Side-Chain Liquid Crystalline Brush Block Copolymers. Macromolecules 2013. [DOI: 10.1021/ma401448j] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Prashant Deshmukh
- Department
of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Suk-kyun Ahn
- Center
for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Polymer
Program, Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269, United States
| | | | - Rajeswari M. Kasi
- Department
of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
- Polymer
Program, Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269, United States
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10
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Dingels C, Müller SS, Steinbach T, Tonhauser C, Frey H. Universal Concept for the Implementation of a Single Cleavable Unit at Tunable Position in Functional Poly(ethylene glycol)s. Biomacromolecules 2013; 14:448-59. [DOI: 10.1021/bm3016797] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Carsten Dingels
- Department of Organic
Chemistry, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, D-55099 Mainz, Germany
| | - Sophie S. Müller
- Department of Organic
Chemistry, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, D-55099 Mainz, Germany
- Graduate School Materials Science in Mainz, Staudingerweg 9, D-55128
Mainz, Germany
| | - Tobias Steinbach
- Department of Organic
Chemistry, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, D-55099 Mainz, Germany
- Graduate School Materials Science in Mainz, Staudingerweg 9, D-55128
Mainz, Germany
| | - Christine Tonhauser
- Department of Organic
Chemistry, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, D-55099 Mainz, Germany
- Graduate School Materials Science in Mainz, Staudingerweg 9, D-55128
Mainz, Germany
| | - Holger Frey
- Department of Organic
Chemistry, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, D-55099 Mainz, Germany
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12
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Zhao J, Schlaad H, Weidner S, Antonietti M. Synthesis of terpene–poly(ethylene oxide)s by t-BuP4-promoted anionic ring-opening polymerization. Polym Chem 2012. [DOI: 10.1039/c1py00388g] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Hofmann AM, Wipf R, Stühn B, Frey H. Mesogen-Initiated Linear Polyglycerol Isomers: The Ordering Effect of a Single Cholesterol Unit on “Sticky” Isotropic Chains. Macromolecules 2011. [DOI: 10.1021/ma201210r] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Anna Maria Hofmann
- Institut für Organische Chemie, Johannes Gutenberg-Universität, Duesbergweg 10-14, 55099 Mainz, Germany
| | - Robert Wipf
- Institut für Festkörperphysik, Technische Universität Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany
| | - Bernd Stühn
- Institut für Festkörperphysik, Technische Universität Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany
| | - Holger Frey
- Institut für Organische Chemie, Johannes Gutenberg-Universität, Duesbergweg 10-14, 55099 Mainz, Germany
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Reuter S, Hofmann AM, Busse K, Frey H, Kressler J. Langmuir and Langmuir-Blodgett films of multifunctional, amphiphilic polyethers with cholesterol moieties. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:1978-1989. [PMID: 21175221 DOI: 10.1021/la104274d] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Langmuir films of multifunctional, hydrophilic polyethers containing a hydrophobic cholesterol group (Ch) were studied by surface pressure-mean molecular area (π-mmA) measurements and Brewster angle microscopy (BAM). The polyethers were either homopolymers or diblock copolymers of linear poly(glycerol) (lPG), linear poly(glyceryl glycidyl ether) (lPGG), linear poly(ethylene glycol) (lPEG), or hyperbranched poly(glycerol) (hbPG). Surface pressure measurements revealed that the homopolymers lPG and hbPG did not stay at the water surface after spreading and solvent evaporation, in contrast to lPEG. Because of the incorporation of the Ch group in the polymer structure, stable Langmuir films were formed by Ch-lPG(n), Ch-lPGG(n), and Ch-hbPG(n). The Ch-hbPG(n), Ch-lPEG(n), Ch-lPEG(n)-b-lPG(m), Ch-lPEG(n)-b-lPGG(m), and Ch-lPEG(n)-b-hbPG(m) systems showed an extended plateau region assigned to a phase transition involving the Ch groups. Typical hierarchically ordered morphologies of the LB films on hydrophilic substrates were observed for all Ch-initiated polymers. All LB films showed that Ch of the Ch-initiated homopolymers is able to crystallize. This strong tendency of self-aggregation then triggers further dewetting effects of the respective polyether entities. Fingerlike morphologies are observed for Ch-lPEG(69), since the lPEG(69) entity is able to undergo crystallization after transfer onto the silicon substrate.
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Affiliation(s)
- Sascha Reuter
- Department of Chemistry, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
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15
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Zhao YL, Erina N, Yasuda T, Kato T, Stoddart JF. A layered liquid crystalline droplet. ACTA ACUST UNITED AC 2009. [DOI: 10.1039/b901917k] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Guo J, Sun J, Cao H, Zhao D, Yang H. Synthesis and characterization of functionalized triblock polymer: The prepared polymer is cholesteryl terminated and chain-extended PCL. J Appl Polym Sci 2007. [DOI: 10.1002/app.26609] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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