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Tu Y, Wen G, Selianitis D, Pispas S. Dense Monolayer Network Structures of Double Hydrophilic Hyperbranched Copolymers at the Air/Water Interface. Macromol Rapid Commun 2024; 45:e2300548. [PMID: 37972570 DOI: 10.1002/marc.202300548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 11/14/2023] [Indexed: 11/19/2023]
Abstract
Influences of subphase pH and temperature on the interfacial aggregation behavior of two double hydrophilic hyperbranched copolymers of poly[oligo(ethylene glycol) methacrylate-co-(2-diisopropylamino)ethyl methacrylate] (P(OEGMA-co-DIPAEMA)) at the air/water interface are studied by the Langmuir film balance technique. Morphologies of their Langmuir-Blodgett (LB) films are characterized by atomic force microscopy (AFM). At the interface, P(OEGMA-co-DIPAEMA) copolymers tend to form a dense network structure of circular micelles composed of branching agent-connected carbon backbone cores and mixed shells of OEGMA and DIPAEMA segments (pendant groups). This network structure containing many honeycomb-like holes with diameters of 6-8 nm is identified for the first time and clearly observed in the enlarged AFM images of their LB films. Under acidic conditions, surface pressure versus molecular area isotherms of the two copolymers in the low-pressure region show larger mean molecular area than those under neutral and alkaline conditions due to the lack of impediment from DIPAEMA segments. Upon further compression, each isotherm exhibits a wide pseudo-plateau, which corresponds to OEGMA segments being pressed into the subphase. Furthermore, the isotherms under neutral and alkaline conditions exhibit the lower critical solution temperature behavior of OEGMA segments, and the critical temperature is lower when the hyperbranched copolymer contains higher OEGMA content.
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Affiliation(s)
- Yongliang Tu
- Department of Polymer Materials and Engineering, School of Material Science and Chemical Engineering, Harbin University of Science and Technology, 4 Linyuan Road, Harbin, 150040, P. R. China
| | - Gangyao Wen
- Department of Polymer Materials and Engineering, School of Material Science and Chemical Engineering, Harbin University of Science and Technology, 4 Linyuan Road, Harbin, 150040, P. R. China
| | - Dimitrios Selianitis
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, Athens, 11635, Greece
| | - Stergios Pispas
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, Athens, 11635, Greece
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Sosso GC, Sudera P, Backes AT, Whale TF, Fröhlich-Nowoisky J, Bonn M, Michaelides A, Backus EHG. The role of structural order in heterogeneous ice nucleation. Chem Sci 2022; 13:5014-5026. [PMID: 35655890 PMCID: PMC9067566 DOI: 10.1039/d1sc06338c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 04/07/2022] [Indexed: 01/10/2023] Open
Abstract
The freezing of water into ice is a key process that is still not fully understood. It generally requires an impurity of some description to initiate the heterogeneous nucleation of the ice crystals. The molecular structure, as well as the extent of structural order within the impurity in question, both play an essential role in determining its effectiveness. However, disentangling these two contributions is a challenge for both experiments and simulations. In this work, we have systematically investigated the ice-nucleating ability of the very same compound, cholesterol, from the crystalline (and thus ordered) form to disordered self-assembled monolayers. Leveraging a combination of experiments and simulations, we identify a “sweet spot” in terms of the surface coverage of the monolayers, whereby cholesterol maximises its ability to nucleate ice (which remains inferior to that of crystalline cholesterol) by enhancing the structural order of the interfacial water molecules. These findings have practical implications for the rational design of synthetic ice-nucleating agents. The freezing of water into ice is still not fully understood. Here, we investigate the role of structural disorder within the biologically relevant impurities that facilitate this fundamental phase transition.![]()
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Affiliation(s)
- Gabriele C Sosso
- Department of Chemistry, University of Warwick Gibbet Hill Road Coventry CV4 7AL UK
| | - Prerna Sudera
- Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
| | - Anna T Backes
- Max Planck Institute for Chemistry Hahn-Meitner-Weg 1 55128 Mainz Germany
| | - Thomas F Whale
- Department of Chemistry, University of Warwick Gibbet Hill Road Coventry CV4 7AL UK
| | | | - Mischa Bonn
- Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
| | - Angelos Michaelides
- Yusuf Hamied Department of Chemistry, University of Cambridge Lensfield Road Cambridge CB2 1EW UK
| | - Ellen H G Backus
- Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany.,Department of Physical Chemistry, University of Vienna Währingerstrasse 42 1090 Wien Austria
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Monolayers of Cholesterol and Cholesteryl Stearate at the Water/Vapor Interface: A Physico-Chemical Study of Components of the Meibum Layer. COLLOIDS AND INTERFACES 2021. [DOI: 10.3390/colloids5020030] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Langmuir monolayers containing different amounts of cholesterol and cholesteryl stearate were studied at two different temperatures (24 °C and 35 °C). The main goal was to contribute towards the understanding of how the variations in the chemical composition may affect the physico-chemical properties of these specific lipid monolayers. The model mixture was chosen considering that cholesteryl esters are present in cell membranes and some other biological systems, including human tear lipids. Therefore, an investigation into the effect of the lipid monolayer composition on their interfacial properties may elucidate some of the fundamental reasons for the deficiencies in cell membranes and tear film functioning in vivo. The experimental results have shown that the molar ratio of the mixture plays a crucial role in the modulation of the Langmuir film properties. The condensing effects of the cholesterol and the interactions between the lipids in the monolayer were the main factors altering the monolayer response to dilatational deformation. The modification of the mixture compositions leads to significant changes in the Langmuir films and the mechanical performance, altering the ability of the monolayer to reduce the surface tension and the viscoelastic properties of the monolayers. This suggests that subtle modifications of the biomembrane composition may significantly alter its physiological function.
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Sarkar A, Suresh KA. Self-assembly and molecular packing in cholesteryl esters at interfaces. J Chem Phys 2017; 146:214702. [PMID: 28576087 PMCID: PMC5453785 DOI: 10.1063/1.4984119] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 05/12/2017] [Indexed: 11/14/2022] Open
Abstract
To understand the self-assembly and molecular packing in cholesteryl esters relevant to biological processes, we have studied them at the air-water and air-solid interfaces. Our phase and thickness studies employing imaging ellipsometry and atomic force microscopy along with surface manometry show that the molecular packing of cholesteryl esters at interfaces can be related to Craven's model of packing, given for bulk. At the air-water interface, following Craven's model, cholesteryl nonanoate and cholesteryl laurate exhibit a fluidic bilayer phase. Interestingly, we find the fluidic bilayer phase of cholesteryl laurate to be unstable and it switches to a crystalline bilayer phase. However, according to Craven, only cholesteryl esters with longer chain lengths starting from cholesteryl tridecanoate should show the crystalline bilayer phase. The thickness behavior of different phases was also studied by transferring the films onto a silicon substrate by using the Langmuir-Blodgett technique. Texture studies show that cholesterol, cholesteryl acetate, cholesteryl nonanoate, cholesteryl laurate, and cholesteryl myristate exhibit homogeneous films with large size domains, whereas cholesteryl palmitate and cholesteryl stearate exhibit less homogeneous films with smaller size domains. We suggest that such an assembly of molecules can be related to their molecular structures. Simulation studies may confirm such a relation.
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Affiliation(s)
- Arup Sarkar
- Centre for Nano and Soft Matter Sciences, P. B. No. 1329, Jalahalli, Bangalore 560013, India
| | - K A Suresh
- Centre for Nano and Soft Matter Sciences, P. B. No. 1329, Jalahalli, Bangalore 560013, India
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Degen P, Wieland DCF, Strötges C. Mixed Layers of Nonionic Dendritic Amphiphiles and DPPC at the Water Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:11851-11857. [PMID: 26447650 DOI: 10.1021/acs.langmuir.5b02702] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Nonionic dendritic amphiphiles that self-assemble into defined supramolecular aggregates are useful for the efficient solubilization of active agents, for example, in drug delivery. We investigated a new class of dendritic amphiphiles based on a hydrophilic polyol dendron head connected to a two-chain hydrophobic block. In analogy to phospholipids, these molecules form well-organized layers in bulk (vesicles) or at the water surface (Langmuir monolayer). The actual study focuses on the phase behavior and microscopic structure of mixed Langmuir layers of theses dendritic amphiphiles with the well-known phospholipid DPPC. The combination of surface pressure area isotherms with X-ray grazing incident diffraction and Brewster angle microscopy gives us information on the phase behavior of the mixed monolayers and the orientation of the amphiphiles inside the condensed domains with molecular resolution. We could prove that the dendritic generation and, by this, the headgroup size of the amphiphilic molecules have a significant influence on their interaction with DPPC at the air-water interface. Thus, our findings are important for the understanding of mixed lipid membranes in general as well as for the preparation of artificial membranes and vesicles with adjustable properties, e.g., their drug delivery potential.
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Affiliation(s)
- Patrick Degen
- Institut für Physikalische Chemie II, Technische Universität Dortmund , Otto-Hahn-Str. 6, 44227 Dortmund, Germany
| | - D C Florian Wieland
- Institut für Metallische Biomaterialien, Helmholtz Zentrum Geestacht , Max-Planck Straße 1, 21502 Geesthacht, Germany
| | - Christian Strötges
- Institut für Physikalische Chemie II, Technische Universität Dortmund , Otto-Hahn-Str. 6, 44227 Dortmund, Germany
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Scholtysek P, Shah SWH, Müller SS, Schöps R, Frey H, Blume A, Kressler J. Unusual triskelion patterns and dye-labelled GUVs: consequences of the interaction of cholesterol-containing linear-hyperbranched block copolymers with phospholipids. SOFT MATTER 2015; 11:6106-6117. [PMID: 26133098 DOI: 10.1039/c5sm01017a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Cholesterol (Ch) linked to a linear-hyperbranched block copolymer composed of poly(ethylene glycol) (PEG) and poly(glycerol) (hbPG) was investigated for its membrane anchoring properties. Two polyether-based linear-hyperbranched block copolymers with and without a covalently attached rhodamine fluorescence label (Rho) were employed (Ch-PEG30-b-hbPG23 and Ch-PEG30-b-hbPG17-Rho). Compression isotherms of co-spread 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) or 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) with the respective polymers were measured on the Langmuir trough and the morphology development of the liquid-condensed (LC) domains was studied by epi-fluorescence microscopy. LC domains were strongly deformed due to the localization of the polymers at the domain interface, indicating a line activity for both block copolymers. Simultaneously, it was observed that the presence of the fluorescence label significantly influences the domain morphology, the rhodamine labelled polymer showing higher line activity. Adsorption isotherms of the polymers to the water surface or to monolayers of DPPC and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), respectively, were collected. Again the rhodamine labelled polymer showed higher surface activity and a higher affinity for insertion into lipid monolayers, which was negligibly affected when the sub-phase was changed to aqueous sodium chloride solution or phosphate buffer. Calorimetric investigations in bulk confirmed the results found using tensiometry. Confocal laser scanning microscopy (CLSM) of giant unilamellar vesicles (GUVs) also confirmed the polymers' fast adsorption to and insertion into phospholipid membranes.
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Affiliation(s)
- Peggy Scholtysek
- Institute of Chemistry, Martin Luther University Halle-Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany.
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On the supramacromolecular structure of core–shell amphiphilic macromolecules derived from hyperbranched polyethyleneimine. J Colloid Interface Sci 2014; 436:243-50. [DOI: 10.1016/j.jcis.2014.06.034] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 06/13/2014] [Accepted: 06/14/2014] [Indexed: 11/22/2022]
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Huan J, Hu L, Fang X. Dense assembly of Gd2O3:0.05X3+ (X = Eu, Tb) nanorods into nanoscaled thin-films and their photoluminescence properties. ACS APPLIED MATERIALS & INTERFACES 2014; 6:1462-1469. [PMID: 24387245 DOI: 10.1021/am4037417] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This paper presents a simple and effective oil-water interfacial self-assembly strategy to fabricate monolayer and bilayer nanofilms of densely packed Gd2O3:0.05X(3+) (X = Eu, Tb) nanorods with characteristic luminescence properties. In this process, Gd2O3:0.05X(3+) (X = Eu, Tb) nanotubes synthesized by a hydrothermal method are dispersed in deionized water; then, a certain amount of n-hexane is added to produce a hexane-water interface. With n-butanol added as initiator, the nanotubes are gradually trapped at the interface to form a densely packed nanofilm. A monolayer nanofilm of densely packed Gd2O3:0.05Eu(3+) nanorods is obtained after annealing. In addition, the bilayer nanofilm composed of Gd2O3:0.05X(3+) (X = Eu, Tb) nanorods still retains the luminescence properties of each monolayer nanofilm. Moreover, the adhesion of the film on the substrate is very strong, which is extremely beneficial for its future applications.
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Affiliation(s)
- Jing Huan
- Department of Materials Science, Fudan University , Shanghai 200433, P. R. China
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Schüll C, Frey H. Grafting of hyperbranched polymers: From unusual complex polymer topologies to multivalent surface functionalization. POLYMER 2013. [DOI: 10.1016/j.polymer.2013.07.065] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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11
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Polyether-Based Lipids Synthesized with an Epoxide Construction Kit: Multivalent Architectures for Functional Liposomes. ACTA ACUST UNITED AC 2013. [DOI: 10.1021/bk-2013-1135.ch002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Samuel AZ, Ramakrishnan S. Self-adapting peripherally heterofunctionalized hyperbranched polymers: formation of Janus and tripodal structures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:1245-1257. [PMID: 23308366 DOI: 10.1021/la304146r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A peripherally clickable hyperbranched polyester carrying numerous propargyl terminal groups was prepared by a simple melt transesterification polycondensation of a suitably designed AB(2) monomer; this clickable hyperscaffold was then transformed into a variety of different derivatives by using the Cu-catalyzed azide-yne click reaction. Functionalization of the periphery with equimolar quantities of mutually immiscible segments, such as hydrocarbon, fluorocarbon, and PEG, yielded frustrated molecular systems that readapt and form structures wherein the immiscible segments appear to self-segregate to generate either Janus structures (when two immiscible segments are present) or tripodal structures (when three immiscible segments are present). Evidence for such self-segregation was obtained from a variety of studies, such as differential scanning calorimetry, Langmuir isotherms, AFM imaging, and small-angle X-ray scattering measurements. Crystallization of one or more of the peripheral segments reinforced this self-segregation; the weight-fraction-normalized enthalpies of melting associated with the different domains revealed a competition between the segments to optimize their crystalline organization. When one or more of the segments are amorphous, the remaining segments crystallize more effectively and consequently exhibit a higher melting enthalpy. AFM images of monolayers, transferred from the Langmuir trough, revealed that the thickness matches the expected values; furthermore, contact angle measurements clearly demonstrated that the monolayer films are fairly hydrophobic, and in the case of the tripodal hybramers, the presence of domains of hydrocarbon and fluorocarbon appears to impart nanoscale chemical heterogeneity that is reflected in the strong hysteresis in the advancing and receding contact angles.
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Affiliation(s)
- Ashok Zachariah Samuel
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
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Mixed DPPC-cholesterol Langmuir monolayers in presence of hydrophilic silica nanoparticles. Colloids Surf B Biointerfaces 2013; 105:284-93. [PMID: 23384691 DOI: 10.1016/j.colsurfb.2013.01.020] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Revised: 12/19/2012] [Accepted: 01/10/2013] [Indexed: 01/14/2023]
Abstract
Langmuir monolayers of Cholesterol (Chol) and a mixture of Chol with 1,2-Dipalmitoyl-sn-glycerol-3-phosphocholine (DPPC), at a ratio of 17:83 in weight, spread on pure water and on silica nanoparticle dispersions, have been investigated measuring the compression isotherms as well as the surface pressure response to harmonic area variation of the monolayer. Aim of this study was to evaluate the effects of the interaction of silica nanoparticles with Chol and the conditions for the incorporation in the monolayer. In previous works on different kind of lipid monolayers, it has been shown that hydrophilic silica nanoparticles dispersed in the sub-phase may transfer into the monolayer, driven by the interaction with the lipid molecules that make them partially hydrophobic. The results here obtained indicate that also for Chol and Chol-DPPC mixtures the presence of silica nanoparticles may have important effects on the phase behaviour and structural properties of the monolayer. As confirmed by complementary structural characterisations, BAM, AFM and ellipsometry, the principal effect of the nanoparticle incorporation is the disruption of the monolayer packing, owing to the alteration of the cohesive interactions of lipid components.
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Schöps R, Amado E, Müller SS, Frey H, Kressler J. Block copolymers in giant unilamellar vesicles with proteins or with phospholipids. Faraday Discuss 2013; 166:303-15. [DOI: 10.1039/c3fd00062a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Degen P, Wyszogrodzka M, Strötges C. Film formation of nonionic dendritic amphiphiles at the water surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:12438-12442. [PMID: 22873403 DOI: 10.1021/la302090k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
This study focuses on the modular synthesis of a new class of nonionic dendritic amphiphiles and their behavior at the water-air interface. Our approach is based on a modular architecture consisting of two different generations of hydrophilic polyol dendrons connected to a two-chain hydrophobic block. Caused by different polarities of polyol and aliphatic groups, the molecules are surface-active and, by analogy to phospholipids, can form well-organized Langmuir monolayers at the water surface. The self-association process and phase behavior of these molecules with two different headgroup sizes were investigated by means of surface pressure and surface potential area isotherms by surface shear rheology and Brewster angle microscopy. With these techniques, we were able to observe marked differences in the phase behavior of the two molecular generations.
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Affiliation(s)
- Patrick Degen
- Institut für Physikalische Chemie II, Technische Universität Dortmund, Dortmund, Germany.
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Peng X, Hofmann AM, Reuter S, Frey H, Kressler J. Mixed layers of DPPC and a linear poly(ethylene glycol)-b-hyperbranched poly(glycerol) block copolymer having a cholesteryl end group. Colloid Polym Sci 2012. [DOI: 10.1007/s00396-012-2613-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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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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Ren Y, Chen M, Hu L, Fang X, Wu L. Oil/water interfacial self-assembly for the organization of hydrophobic NaYF4:Yb, Er nanoplatelets into closely-packed fluorescent nanofilms. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c1jm13381k] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Hofmann AM, Wurm F, Frey H. Rapid Access to Polyfunctional Lipids with Complex Architecture via Oxyanionic Ring-Opening Polymerization. Macromolecules 2011. [DOI: 10.1021/ma200367c] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Anna Maria Hofmann
- Institut für Organische Chemie, Johannes Gutenberg-Universität, Duesbergweg 10-14, 55099 Mainz, Germany
| | - Frederik Wurm
- Institut des Matériaux, Laboratoire des Polymères Batiment MXD, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 12, 1015 Lausanne, Switzerland
| | - Holger Frey
- Institut für Organische Chemie, Johannes Gutenberg-Universität, Duesbergweg 10-14, 55099 Mainz, Germany
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