Full text
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| Author(s): |
Celize Maia Tcacenco
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ) |
| Defense date: | 2000-04-13 |
| Examining board members: |
Frank Herbert Quina;
Luiz Henrique Catalani;
Maria Elisabete Darbello Zaniquelli
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| Advisor: | Frank Herbert Quina |
| Abstract | |
In this dissertation, the technique of time-resolved fluorescence quenching has been employed to investigate the dynamics of intrapolymeric aggregation of the [3,22]-ionene and the interaction of the resultant aggregates with coions and counterions. Undesirable quenching of the fluorescence of pyrene solubilized in [3,22]-ionene bromide was eliminated by quaternization of the amino terminal groups with benzyl chloride and by exchanging the counterion from Br- to Cl-, to give NT-benzyl-[3,22]-ionene chloride. Measurements of the dynamics of excimer formation by pyrene and its derivatives showed that, in contrast to cetyltrimethyanonium chloride (CTACl) micelles, the NT-benzyl-[3,22]-ionene aggregates undergoe an efficient intrapolymeric fusion/fission process that promotes the migration of probes and quencher between the aggregates. The existence of this intrapolymeric process requires that there be various microdomains distributed along the main ionene chain. At low temperature (<15°C), where the intrapolymeric fusion/fission process becomes much slower than quenching, an estimate of 20.5 ionene subunits is obtained for the aggregation number of the microdomains. The rate constant for the fusion/fission process (kfus) was estimated from the dynamics of excimer formation of pyrene and its derivatives. Data for the dynamics of exit of coions and counterions from the microdomains of NT-benzyl-[3,22]-ionene were analyzed by taking into account two simultaneous migration mechanisms: via the aqueous phase and via the fusion/fission route. The added common salt concentration dependences of the rate constants for exit and quenching are similar for both the NTbenzyl-[3,22]-ionene microdomains and CTACl micelles. (AU) | |