Photodegradation of poly(ethylene oxide) and its coordination complexes with iron(III)chloride

Poly(ethylene oxide) (PEO) forms coordination complexes with iron(III) chloride (ferric chloride, FeCl 3). The morphological structure of these complexes depends very much on the weight ratio of PEO/FeCl 3. The complexes at PEO/FeCl 3 ratios of 7:3 and 5:5 are high-viscosity liquids in which different morphological forms crystallize, such as dendrites and needle-crystals. Both PEO and PEO-FeCl 3 complexes are very susceptible to UV photodegradation. The presence of the FeCl 3 in these complexes markedly accelerates their photodecomposition. Chlorine radicals are probably responsible for this reaction and are formed from FeCl 4 − ions present in these complexes. The PEO-FeCl 3 complexes also exhibit a photochromic effect, which partially disappears during UV photodegradation.