Photoinduced electron transfer at the core/shell interface of polystyrene-anthracene-poly(methacrylic acid) diblock copolymer micelles in aqueous media

Journal Article · Thu Feb 27 04:00:00 EST 1997 · Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory

DOI:https://doi.org/10.1021/jp962891w· OSTI ID:505195

Eckert, A R; Martin, T J; Webber, S E ^[1]

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1. Univ. of Texas, Austin, TX (United States)

We have characterized the photophysics and excited-state electron transfer reactions of polymer micelles formed from diblock polystyrene-(anthracene)-block-poly(methacrylic acid). In these studies (anthracene) comprises either a single 1-(2-anthryl)-1-phenylethylene (An) or an average of two vinyl-9,10-diphenylanthracene (vDPA). This architecture is expected to place the chromophores in the interfacial region between the polystyrene core and poly(methacrylic acid) corona. Quenching of the anthryl fluorescence by Tl{sup +} and two viologens (SPV, 4,4`-bipyridyl-1,1`-bis(propanesulfonate), and MV{sup 2+}, methyl viologen) demonstrated that access to these chromophores was limited at all pHs, and the rate of diffusion of the viologens was relatively slow. Similar conclusions were drawn from quenching of the {sup 3}An{sup *} state and the anion radical SPV{sup {center_dot}-} by O{sub 2}. We believe this illustrates that the interfacial region of the micelle is not fully deprotonated even at pH 9. It was observed that the fraction of {sup 3}An{sup *} that was quenched by SPV was smaller than {sup 1}An{sup *}. This demonstrates the existence of a heterogeneous distribution of anthryl sites such that some {sup 3}An{sup *} cannot be quenched, which is not the case for {sup 1}An{sup *}. We conclude that the spatial requirements for quenching these two excited states are not equivalent. 53 refs., 9 figs., 9 tabs.

• OSTI ID: 505195
• Journal Information: Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory, Journal Name: Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory Journal Issue: 9 Vol. 101; ISSN 1089-5639; ISSN JPCAFH
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
40 CHEMISTRY
ABSORPTION SPECTRA
ANTHRACENE
CHEMICAL REACTION KINETICS
COPOLYMERS
ELECTRON TRANSFER
EXCITED STATES
FLUORESCENCE
INTERFACES
MICELLAR SYSTEMS
NUMERICAL DATA
PH VALUE
PHOTOLYSIS
POLYSTYRENE
QUENCHING
ULTRAVIOLET SPECTRA