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Molecular dynamics simulation of amphiphilic bistable [2]rotaxane Langmuir monolayers at the air/water interface
DC Field | Value | Language |
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dc.contributor.author | Jang, SS | - |
dc.contributor.author | Jang, YH | - |
dc.contributor.author | Kim, YH | - |
dc.contributor.author | Goddard, WA | - |
dc.contributor.author | Choi, Jang Wook | - |
dc.contributor.author | Heath, JR | - |
dc.contributor.author | Laursen, BW | - |
dc.contributor.author | Flood, AH | - |
dc.contributor.author | Stoddart, JF | - |
dc.contributor.author | Norgaard, K | - |
dc.contributor.author | Bjornholm, T | - |
dc.date.accessioned | 2020-03-16T11:07:22Z | - |
dc.date.available | 2020-03-16T11:07:22Z | - |
dc.date.created | 2018-07-02 | - |
dc.date.issued | 2005-10 | - |
dc.identifier.citation | Journal of the American Chemical Society, Vol.127 No.42, pp.14804-14816 | - |
dc.identifier.issn | 0002-7863 | - |
dc.identifier.other | 38475 | - |
dc.identifier.uri | https://hdl.handle.net/10371/164615 | - |
dc.description.abstract | Bistable [2]rotaxanes display controllable switching properties in solution, on surfaces, and in devices. These phenomena are based on the electrochemically and electrically driven mechanical shuttling motion of the ring-shaped component, cyclobis(paraquat-p-phenylene) (CBPOT4+), between a monopyrrolotetrathiafulvalene (mpTTF) unit and a 1,5-dioxynaphthalene (DNP) unit located along a dumbbell component. The most stable state of the rotaxane (CBPQT(4+) @ mpTTF) is that in which the CBPQT(4+) ring encircles the mpTTF unit, but a second less favored metastable co-conformation with the CBPQT(4+) ring surrounding the DNP (CBPQT(4+) @ DNP) can be formed experimentally. For both co-conformations of an amphiphilic bistable [2]rotaxane, we report here the structure and surface pressure-area isotherm of a Langmuir monolayer (LM) on a water subphase as a function of the area per molecule. These results from atomistic molecular dynamics (MD) studies are validated by comparing with experiments based on similar amphiphilic rotaxanes. For both co-conformations, we found that as the area per molecule increases the thickness of the LM decreases while the molecular tilt increases. Both co-conformations led to similar LM thicknesses at the same packing area. From the simulated LM systems, we calculated the electron density profiles of the monolayer as a function of area per molecule, which show good agreement with experimental analyses from synchrotron X-ray reflectivity measurements of related systems. Decomposing the overall electron density profiles into component contributions, we found distinct differences in molecular packing in the film depending upon the co-conformation. Thus we find that the necessity of allowing the tetracationic ring to become solvated by water leads to differences in the structures for the two co-conformations in the LM. At the same packing area, the value of the overall tilt angle does not seem to be sensitive to whether the CBPQT(4+) ring is encircling the mpTTF or the DNP unit. However, the conformation of the dumbbell does depend on the location of the CBPQT(4+) ring, which is reflected in the segmental tilt angles of the mpTTF and DNP units. Using the Kirkwood-Buff formula in conjunction with MD calculations, we find the surface pressure-area isotherms for each co-conformation in which the CBPQT(4+) @ mpTTF form has smaller surface tension and therefore larger surface pressure than the CBPQT(4+) @ DNP at the same packing area, differences that decreases with increasing area per molecule, which is verified experimentally. | - |
dc.language | 영어 | - |
dc.publisher | American Chemical Society | - |
dc.title | Molecular dynamics simulation of amphiphilic bistable [2]rotaxane Langmuir monolayers at the air/water interface | - |
dc.type | Article | - |
dc.contributor.AlternativeAuthor | 최장욱 | - |
dc.identifier.doi | 10.1021/ja0531531 | - |
dc.citation.journaltitle | Journal of the American Chemical Society | - |
dc.identifier.wosid | 000232780900056 | - |
dc.identifier.scopusid | 2-s2.0-27144550143 | - |
dc.citation.endpage | 14816 | - |
dc.citation.number | 42 | - |
dc.citation.startpage | 14804 | - |
dc.citation.volume | 127 | - |
dc.identifier.sci | 000232780900056 | - |
dc.description.isOpenAccess | N | - |
dc.contributor.affiliatedAuthor | Choi, Jang Wook | - |
dc.type.docType | Article | - |
dc.description.journalClass | 1 | - |
dc.subject.keywordPlus | AMORPHOUS-SILICON | - |
dc.subject.keywordPlus | SIZE | - |
dc.subject.keywordPlus | NANOCOMPOSITES | - |
dc.subject.keywordPlus | NANOWIRES | - |
dc.subject.keywordPlus | ELECTRODE | - |
dc.subject.keywordPlus | STORAGE | - |
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