Vana, Philipp

[["dc.bibliographiccitation.firstpage","1473"],["dc.bibliographiccitation.issue","11"],["dc.bibliographiccitation.journal","Australian Journal of Chemistry"],["dc.bibliographiccitation.lastpage","1478"],["dc.bibliographiccitation.volume","62"],["dc.contributor.author","Rotzoll, Robert"],["dc.contributor.author","Vana, Philipp"],["dc.date.accessioned","2018-11-07T08:33:50Z"],["dc.date.available","2018-11-07T08:33:50Z"],["dc.date.issued","2009"],["dc.description.abstract","The present study introduces the silica-anchored azo-initiator 4,4'-azobis(4-cyano-N-(3 '-triethoxysilylpropyl)-valeric amide) (ACTA) for the surface-initiated polymerization of methyl acrylate (MA) with and without additional grafted reversible addition-fragmentation chain transfer (RAFT) agents 1,4-bis(3'-trimethoxysilylpropyltrithiocarbonylmethyl)benzene and 1,6-bis(o,p-2'-trimethoxysilylethylbenzyltrithiocarbonyl)hexane. While the sole use of silica-linked ACTA produced grafted poly(methyl acrylate) (pMA) of high molecular weight, due to a 2D Trommsdorff effect, the polymerization in combination with the fixed RAFT agents exhibited living behaviour with increasing molecular weights during polymerization. Silica-pMA hybrids were further analyzed via thermogravimetric analysis and scanning electron microscopy, which revealed significant differences between the three approaches."],["dc.description.sponsorship","Deutsche Forschungsgemeinschaft [VA226/4-1]"],["dc.identifier.doi","10.1071/CH09189"],["dc.identifier.isi","000271976400005"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/17682"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Csiro Publishing"],["dc.relation.issn","0004-9425"],["dc.title","A Bipedal Silica-Immobilized Azo-Initiator for Surface-Confined Radical Polymerizations"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","2007"],["dc.bibliographiccitation.issue","7"],["dc.bibliographiccitation.journal","Organic Letters"],["dc.bibliographiccitation.lastpage","2010"],["dc.bibliographiccitation.volume","20"],["dc.contributor.author","Khan, Taukeer A."],["dc.contributor.author","Fornefeld, Torsten"],["dc.contributor.author","Hübner, Dennis"],["dc.contributor.author","Vana, Philipp"],["dc.contributor.author","Tietze, Lutz F."],["dc.date.accessioned","2018-08-14T15:26:49Z"],["dc.date.available","2018-08-14T15:26:49Z"],["dc.date.issued","2018"],["dc.description.abstract","A palladium-catalyzed 4-fold domino reaction consisting of two carbopalladation reactions and two C–H activation reactions, followed by the introduction of an acrylate moiety, led to the tetra-substituted helical alkene A2, using the dialkyne A3 as a substrate. The alkene was copolymerized with butyl acrylate by using the reversible addition–fragmentation chain transfer polymerization (RAFT) to give the desired polymeric switch A1."],["dc.identifier.doi","10.1021/acs.orglett.8b00553"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/15296"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.title","Palladium-Catalyzed 4-Fold Domino Reaction for the Synthesis of a Polymeric Double Switch"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1484"],["dc.bibliographiccitation.issue","11"],["dc.bibliographiccitation.journal","Australian Journal of Chemistry"],["dc.bibliographiccitation.lastpage","1487"],["dc.bibliographiccitation.volume","62"],["dc.contributor.author","Buback, Michael"],["dc.contributor.author","Meiser, Wibke"],["dc.contributor.author","Vana, Philipp"],["dc.date.accessioned","2018-11-07T08:33:50Z"],["dc.date.available","2018-11-07T08:33:50Z"],["dc.date.issued","2009"],["dc.description.abstract","Reversible addition-fragmentation chain transfer (RAFT) polymerizations of methyl methacrylate (MMA) in bulk at 60 degrees C were performed at five pressures up to 200 MPa using 2-(2'-cyanopropyl)dithiobenzoate (CPDB) as RAFT agent at concentrations between 1.5 x 10(-3) and 2.0 x 10(-2) mol L(-1). Applying high pressure during polymerization increases the rate of polymerization, but no effect on polydispersity was observed. Molecular weight distributions and average molecular weights of the final polymer indicated the successful control of MMA polymerization even at low CPDB concentrations. The slight retardation observed is adequately described by the dependence the termination rate coefficient, k(t), on the chain-length."],["dc.identifier.doi","10.1071/CH09219"],["dc.identifier.isi","000271976400007"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/17683"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Csiro Publishing"],["dc.relation.issn","0004-9425"],["dc.title","Mechanism of CPDB-Mediated RAFT Polymerization of Methyl Methacrylate: Influence of Pressure and RAFT Agent Concentration"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.journal","Nature Sustainability"],["dc.contributor.author","Wang, Jiaxiu"],["dc.contributor.author","Emmerich, Lukas"],["dc.contributor.author","Wu, Jianfeng"],["dc.contributor.author","Vana, Philipp"],["dc.contributor.author","Zhang, Kai"],["dc.date.accessioned","2021-08-12T07:45:02Z"],["dc.date.available","2021-08-12T07:45:02Z"],["dc.date.issued","2021"],["dc.identifier.doi","10.1038/s41893-021-00743-1"],["dc.identifier.pii","743"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/88357"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-448"],["dc.relation.eissn","2398-9629"],["dc.title","Hydroplastic polymers as eco-friendly hydrosetting plastics"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","5590"],["dc.bibliographiccitation.issue","19"],["dc.bibliographiccitation.journal","Polymer"],["dc.bibliographiccitation.lastpage","5598"],["dc.bibliographiccitation.volume","48"],["dc.contributor.author","Buback, Michael"],["dc.contributor.author","Frauendorf, Holm"],["dc.contributor.author","GUnzler, Fabian"],["dc.contributor.author","Vana, Philipp"],["dc.date.accessioned","2018-11-07T10:58:38Z"],["dc.date.available","2018-11-07T10:58:38Z"],["dc.date.issued","2007"],["dc.description.abstract","The type and number of end groups of poly(methyl methacrylates) from free-radical polymerization with six diacyl peroxides, R-(CO)O- O(CO)-R. acting as initiators have been analyzed via electrospray ionization mass spectrometry using an ion trap and additionally Fourier transform ion cyclotron resonance for mass detection. The polymerizations were carried out in benzene solution at high initiator concentration to yield low molecular weight polymer. With R being an alkyl group, only R moieties are observed as end groups. For each oligomer size, molecules with one or two such end groups are formed, depending on whether termination occurs via disproportionation or combination. With R being an aryl type, as in di-benzoyl and di-naphthoyl peroxides, both R and R-(CO)O moieties are detected as polymeric end groups. Because of aromatic delocalization. fractions of the arylic R-(CO)O-center dot radicals are sufficiently long living at 95 degrees C to add to a monomer molecule prior to undergo decarboxylation. (C) 2007 Elsevier Ltd. All rights reserved."],["dc.identifier.doi","10.1016/j.polymer.2007.07.041"],["dc.identifier.isi","000250161000018"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/50507"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Sci Ltd"],["dc.relation.issn","0032-3861"],["dc.title","Electrospray ionization mass spectrometric end-group analysis of PMMA produced by radical polymerization using diacyl peroxide initiators"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","779"],["dc.bibliographiccitation.issue","10"],["dc.bibliographiccitation.journal","Australian Journal of Chemistry"],["dc.bibliographiccitation.lastpage","787"],["dc.bibliographiccitation.volume","60"],["dc.contributor.author","Buback, Michael"],["dc.contributor.author","Hesse, Pascal"],["dc.contributor.author","Junkers, Thomas"],["dc.contributor.author","Theis, Thomas"],["dc.contributor.author","Vana, Philipp"],["dc.date.accessioned","2018-11-07T11:06:03Z"],["dc.date.available","2018-11-07T11:06:03Z"],["dc.date.issued","2007"],["dc.description.abstract","The chain-length dependence of the termination rate coefficient, k(t), in methyl acrylate ( MA) and dodecyl acrylate (DA) radical polymerization has been determined via the single pulse pulsed-laser polymerization near-infrared reversible addition-fragmentation chain transfer (SP-PLP-NIR-RAFT) technique. Polymerization is induced by a laser SP and the resulting decay in monomer concentration, c(M), is monitored via NIR spectroscopy with a time resolution of microseconds. A RAFT agent ensures the correlation of radical chain length and monomer-to-polymer conversion. The obtained rate coefficients for termination of two radicals of approximately the same chain length, i, are represented by power-law expressions, k(t)(i, i)alpha i(-alpha). For both monomers, composite model behaviour of k(t)(i, i) showing two distinct chain length regimes is observed. The exponent as referring to short chain lengths is close to unity, whereas the exponent alpha(1), which characterizes the chain-length dependency of large radicals, is slightly above the theoretical value for coiled chain-end radicals. The crossover chain length, i(c), which separates the two regions, decreases from MA(i(c) = 30) to DA(i(c) = 20). The results for MA and DA are consistent with earlier data reported for butyl acrylate. There appears to be a correlation of as and ic with chain flexibility."],["dc.identifier.doi","10.1071/CH07236"],["dc.identifier.isi","000250003800010"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/52214"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Csiro Publishing"],["dc.publisher.place","Clayton"],["dc.relation.conference","29th Australasian Polymer Symposium"],["dc.relation.eventlocation","Hobart, AUSTRALIA"],["dc.relation.issn","1445-0038"],["dc.relation.issn","0004-9425"],["dc.title","Chain-length-dependent termination in acrylate radical polymerization studied via pulsed-laser-initiated RAFT polymerization"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1299"],["dc.bibliographiccitation.issue","16"],["dc.bibliographiccitation.journal","Macromolecular Rapid Communications"],["dc.bibliographiccitation.lastpage","1305"],["dc.bibliographiccitation.volume","27"],["dc.contributor.author","Buback, Michael"],["dc.contributor.author","Vana, Philipp"],["dc.date.accessioned","2018-11-07T09:25:01Z"],["dc.date.available","2018-11-07T09:25:01Z"],["dc.date.issued","2006"],["dc.description.abstract","The debate on the mechanism of dithiobenzoate-mediated RAFT polymerization may be resolved by including the reaction between a propagating radical and the star-shaped combination product from irreversible termination into the kinetic scheme. By this step, a highly reactive propagating radical and a not overly stable three-arm star species are transformed into the resonance-stabilized RAFT intermediate radical and a very stable polymer molecule. The time evolution of concentration is discussed for the main-equilibrium range of CDB-mediated methyl acrylate polymerization."],["dc.identifier.doi","10.1002/marc.200600317"],["dc.identifier.isi","000240426600001"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/29969"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-blackwell"],["dc.relation.issn","1022-1336"],["dc.title","Mechanism of dithiobenzoate-mediated RAFT polymerization: A missing reaction step"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","2404"],["dc.bibliographiccitation.issue","7"],["dc.bibliographiccitation.journal","Macromolecules"],["dc.bibliographiccitation.lastpage","2410"],["dc.bibliographiccitation.volume","37"],["dc.contributor.author","Feldermann, A."],["dc.contributor.author","Stenzel, M. H."],["dc.contributor.author","Davis, T. P."],["dc.contributor.author","Vana, P."],["dc.contributor.author","Barner-Kowollik, C."],["dc.date.accessioned","2018-11-07T10:49:39Z"],["dc.date.available","2018-11-07T10:49:39Z"],["dc.date.issued","2004"],["dc.description.abstract","A recently developed methodology for determining chain length dependent termination rate coefficients, (k(t)(i,i)), via reversible addition-fragmentation chain transfer (RAFT) polymerizations has been extended and validated for 1-phenylethyl phenyldithioacetate (PEPDA) and 3-benzylsulfanylthiocarbonylsulfanylpropionic acid (BSPA) mediated styrene (bulk) free radical polymerizations at 80 degreesC. While the use of cumyl phenyldithioacetate (CPDA) enables a highly precise mapping of the chain length dependence of the termination rate coefficient, employment of PEPDA and BSPA leads to considerable information loss for short chain lengths (i < 10). Careful simulations demonstrate that such behavior is caused by a substantial decrease in the initial transfer effectiveness of the RAFT agents when going from CPDA to BSPA, leading to hybrid behavior between conventional and living free radical polymerization. The observed hybrid behavior is quantifiable via (overall) transfer rate coefficients for the individual RAFT agents in the preequilibrium step [CPDA (k(tr,R) = 5.0 x 10(5) L mol(-1) s(-1)), PEPDA (k(tr,R) = 2.0 x 10(5) L mol(-1) s(-1)), and BSPA (k(tr,R) = 1.0 x 10(4) L mol(-1) s(-1)) at 80 degreesC] The underlying structural cause is the change from a tertiary (CPDA), via a secondary (PEPDA), to a primary (BSPA) leaving group in the initial RAFT agent. Further, the presented simulations open an efficient pathway for approximating overall preequilibrium transfer rate coefficients for the employed RAFT agents."],["dc.identifier.doi","10.1021/ma0358428"],["dc.identifier.isi","000220581700011"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/48476"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Chemical Soc"],["dc.relation.issn","0024-9297"],["dc.title","Facile access to chain length dependent termination rate coefficients via reversible addition-fragmentation chain transfer (RAFT) polymerization: Influence of the RAFT agent structure"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","1700126"],["dc.bibliographiccitation.firstpage","1"],["dc.bibliographiccitation.issue","17"],["dc.bibliographiccitation.journal","Macromolecular Chemistry and Physics"],["dc.bibliographiccitation.lastpage","8"],["dc.bibliographiccitation.volume","218"],["dc.contributor.author","Kokubo, Shinsuke"],["dc.contributor.author","Vana, Philipp"],["dc.date.accessioned","2018-08-14T16:20:34Z"],["dc.date.available","2018-08-14T16:20:34Z"],["dc.date.issued","2017"],["dc.description.abstract","Ion-mobility mass spectrometry of doubly charged polyethylene glycol (PEG) is performed after electrospray-ionization time-of-flight mass spectrometry and the dependency of the effective collision cross-section, CCSeff, on the number of monomer units, n, is evaluated with the help of molecular dynamics simulations. Assuming a balance between elastic and Coulomb forces inside short and asymmetric doubly charged chains, a method is developed for evaluating the dielectric constant, ε, which is found to be 7.87 for PEG for n = 14-28. From the same experiment at higher chain lengths, the characteristic ratio Cn of 4.30 for PEG (n ≥ 63) can be evaluated according to an earlier reported method, which is demonstrated here to also work with doubly charged species. The proposed method enables an extremely swift and precise measurement both of ε and Cn of polymer that is free of solvent or impurities from one single experiment."],["dc.identifier.doi","10.1002/macp.201700126"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/15302"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.title","Obtaining the Dielectric Constant of Polymers from Doubly Charged Species in Ion‐Mobility Mass Spectrometry"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","1702473"],["dc.bibliographiccitation.firstpage","1"],["dc.bibliographiccitation.issue","43"],["dc.bibliographiccitation.journal","Advanced Materials"],["dc.bibliographiccitation.lastpage","8"],["dc.bibliographiccitation.volume","29"],["dc.contributor.author","Wang, Yonggui"],["dc.contributor.author","Groszewicz, Pedro Braga"],["dc.contributor.author","Rosenfeldt, Sabine"],["dc.contributor.author","Schmidt, Hendrik"],["dc.contributor.author","Volkert, Cynthia A."],["dc.contributor.author","Vana, Philipp"],["dc.contributor.author","Gutmann, Torsten"],["dc.contributor.author","Buntkowsky, Gerd"],["dc.contributor.author","Zhang, Kai"],["dc.date.accessioned","2018-08-14T16:15:11Z"],["dc.date.accessioned","2020-05-14T13:29:54Z"],["dc.date.available","2018-08-14T16:15:11Z"],["dc.date.available","2020-05-14T13:29:54Z"],["dc.date.issued","2017"],["dc.description.abstract","Self-assembly of nanoparticles (NPs) forming unique structures has been investigated extensively over the past few years. However, many self-assembled structures by NPs are irreversible, because they are generally constructed using their suspensions. It is still challenging for NPs to reversibly self-assemble in dry state, let alone of polymeric NPs with general sizes of hundreds of nm. Herein, this study reports a new reversible self-assembly phenomenon of NPs in dry state, forming thermoreversible strip-like supermolecular structures. These novel NPs of around 150 nm are perfluorinated surface-undecenoated cellulose nanoparticles (FSU-CNPs) with a core-coronas structure. The thermoreversible self-assembled structure is formed after drying in the air at the interface between FSU-CNP films and Teflon substrates. Remarkably, the formation and dissociation of this assembled structure are accompanied by a reversible conversion of the surface hydrophobicity, film transparency, and anisotropic properties. These findings show novel feasibility of reversible self-assembly of NPs in dry state, and thereby expand our knowledge of self-assembly phenomenon."],["dc.identifier.doi","10.1002/adma.201702473"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/65433"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/15301"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.relation.orgunit","Institut für Materialphysik"],["dc.title","Thermo-Reversible Self-Assembly of Perfluorinated Core-Coronas Cellulose-Nanoparticles in Dry State"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]