Aggregation and photophysics of Rose Bengal in alumina-coated colloidal suspensions
The absorption and emission properties of Rose Bengal (RB) have been studied in colloidal suspensions of positively charged alumina-coated silica nanoparticles (Sil). Experimental spectra can be rationalized by the existence of an equilibrium between aqueous monomers and only one adsorbed species. H...
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_0018019X_v84_n9_p2601_Daraio |
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todo:paper_0018019X_v84_n9_p2601_Daraio2023-10-03T14:15:07Z Aggregation and photophysics of Rose Bengal in alumina-coated colloidal suspensions Daraio, M.E. San Román, E. Absorption Agglomeration Dimers Fluorescence Monomers Positive ions Silica Photophysics Suspensions (fluids) aluminum oxide cation dimer nanoparticle rose bengal silicon dioxide absorption adsorption aqueous solution article chemical structure colloid fluorescence mathematical analysis photochemistry The absorption and emission properties of Rose Bengal (RB) have been studied in colloidal suspensions of positively charged alumina-coated silica nanoparticles (Sil). Experimental spectra can be rationalized by the existence of an equilibrium between aqueous monomers and only one adsorbed species. However, a simple partition or a Langmuir-type adsorption-aggregation equilibrium do not explain the observed results. No evidence regarding the existence of adsorbed monomers is found even at low surface coverage. Aggregation stops at the dimer level, though, at high enough dye concentrations, the surface coverage is almost complete. Comparative experiments performed on negatively charged silica nanoparticles show that monomers are the only species present in this case. Fluorescence experiments on Sil indicate that dimers are fluorescent. Laser excitation of adsorbed dye leads to the formation of RB radical cations, while the dye triplet state is not observed. Fil:Daraio, M.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:San Román, E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_0018019X_v84_n9_p2601_Daraio |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Absorption Agglomeration Dimers Fluorescence Monomers Positive ions Silica Photophysics Suspensions (fluids) aluminum oxide cation dimer nanoparticle rose bengal silicon dioxide absorption adsorption aqueous solution article chemical structure colloid fluorescence mathematical analysis photochemistry |
| spellingShingle |
Absorption Agglomeration Dimers Fluorescence Monomers Positive ions Silica Photophysics Suspensions (fluids) aluminum oxide cation dimer nanoparticle rose bengal silicon dioxide absorption adsorption aqueous solution article chemical structure colloid fluorescence mathematical analysis photochemistry Daraio, M.E. San Román, E. Aggregation and photophysics of Rose Bengal in alumina-coated colloidal suspensions |
| topic_facet |
Absorption Agglomeration Dimers Fluorescence Monomers Positive ions Silica Photophysics Suspensions (fluids) aluminum oxide cation dimer nanoparticle rose bengal silicon dioxide absorption adsorption aqueous solution article chemical structure colloid fluorescence mathematical analysis photochemistry |
| description |
The absorption and emission properties of Rose Bengal (RB) have been studied in colloidal suspensions of positively charged alumina-coated silica nanoparticles (Sil). Experimental spectra can be rationalized by the existence of an equilibrium between aqueous monomers and only one adsorbed species. However, a simple partition or a Langmuir-type adsorption-aggregation equilibrium do not explain the observed results. No evidence regarding the existence of adsorbed monomers is found even at low surface coverage. Aggregation stops at the dimer level, though, at high enough dye concentrations, the surface coverage is almost complete. Comparative experiments performed on negatively charged silica nanoparticles show that monomers are the only species present in this case. Fluorescence experiments on Sil indicate that dimers are fluorescent. Laser excitation of adsorbed dye leads to the formation of RB radical cations, while the dye triplet state is not observed. |
| format |
JOUR |
| author |
Daraio, M.E. San Román, E. |
| author_facet |
Daraio, M.E. San Román, E. |
| author_sort |
Daraio, M.E. |
| title |
Aggregation and photophysics of Rose Bengal in alumina-coated colloidal suspensions |
| title_short |
Aggregation and photophysics of Rose Bengal in alumina-coated colloidal suspensions |
| title_full |
Aggregation and photophysics of Rose Bengal in alumina-coated colloidal suspensions |
| title_fullStr |
Aggregation and photophysics of Rose Bengal in alumina-coated colloidal suspensions |
| title_full_unstemmed |
Aggregation and photophysics of Rose Bengal in alumina-coated colloidal suspensions |
| title_sort |
aggregation and photophysics of rose bengal in alumina-coated colloidal suspensions |
| url |
http://hdl.handle.net/20.500.12110/paper_0018019X_v84_n9_p2601_Daraio |
| work_keys_str_mv |
AT daraiome aggregationandphotophysicsofrosebengalinaluminacoatedcolloidalsuspensions AT sanromane aggregationandphotophysicsofrosebengalinaluminacoatedcolloidalsuspensions |
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1782028465972707328 |