| Summary: | The incorporation of three conjugated polymers: MEH-PPV, DP-PPV and DP10-
PPV into porous alumina films on Al, Si and ITO substrates via an adsorption process is
reported. The nature of this adsorption process involves bonding between Lewis acidic Al
centres on the alumina and the Lewis basic polymer backbone. The MEH-PPV porous
alumina hybrids was found to degrade rapidly upon the irradiation of UV-light (λext = 366
nm) in air but to a lesser extent in the dark and under nitrogen. Silanization of the pores
by treatment with trimethylchlorosilane (TMS), phenyldimethylchlorosilane (PDMS) and
octyldimethylchlorosilane (ODMS) resulted in lower MEH-PPV loading in porous
alumina membranes (Anodisc 13) relative to the membranes with unmodified pore walls.
In the fluorescence spectra, the intensity of the fluorescence from the Anodisc
membranes containing MEH-PPV is higher than from MEH-PPV in silanized porous
alumina. The Lewis acidic Al centres of the porous alumina in the silanized pores are
screened from the Lewis basic polymer resulting in a lower fluorescence intensity.
Within the silanes used, the absorbance intensity is in the order: TMS > ODMS, PDMS.
Within the silanes, the difference in fluorescence intensities may be due to the size of the
alkyl/aryl groups. The larger alkyl substituent in ODMS and the aryl group in PDMS
may act to better screen the Lewis acidic Al than in the smaller alkyl group in TMS. In
DP10-PPV, the unmodified porous alumina has a higher fluorescence intensity relative to
the modified materials. This is attributed to the interactions between the pore walls and
the polymer. The same screening effect that occurs for MEH-PPV is also observed for
DP10-PPV. For DP10-PPV, the fluorescence intensities is in the order: PDMS > ODMS,
TMS. This difference may arise from the favourable π-stacking interactions between the
polymer and the PDMS silanized pores. === Science, Faculty of === Chemistry, Department of === Graduate
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