RESUMO
Microbial biofilms cause the deterioration of polymeric coatings such as polyurethanes (PUs). In many cases, microbes have been shown to use the PU as a nutrient source. The interaction between biofilms and nutritive substrata is complex, since both the medium and the substratum can provide nutrients that affect biofilm formation and biodeterioration. Historically, studies of PU biodeterioration have monitored the planktonic cells in the medium surrounding the material, not the biofilm. This study monitored planktonic and biofilm cell counts, and biofilm morphology, in long-term growth experiments conducted with Pseudomonas fluorescens under different nutrient conditions. Nutrients affected planktonic and biofilm cell numbers differently, and neither was representative of the system as a whole. Microscopic examination of the biofilm revealed the presence of intracellular storage granules in biofilms grown in M9 but not yeast extract salts medium. These granules are indicative of nutrient limitation and/or entry into stationary phase, which may impact the biodegradative capability of the biofilm.
Assuntos
Biofilmes/crescimento & desenvolvimento , Incrustação Biológica/prevenção & controle , Pintura , Poliuretanos , Pseudomonas fluorescens , Biofilmes/efeitos dos fármacos , Materiais de Construção/microbiologia , Meios de Cultura , Grânulos Citoplasmáticos/efeitos dos fármacos , Grânulos Citoplasmáticos/fisiologia , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Pintura/microbiologia , Pintura/normas , Plâncton/efeitos dos fármacos , Plâncton/crescimento & desenvolvimento , Poliuretanos/normas , Pseudomonas fluorescens/efeitos dos fármacos , Pseudomonas fluorescens/crescimento & desenvolvimento , Pseudomonas fluorescens/fisiologia , Espectrometria por Raios X , Propriedades de SuperfícieAssuntos
Cristais Líquidos/química , Temperatura , Cor , Polimerização , Análise Espectral , Propriedades de SuperfícieRESUMO
A structured polymer was synthesized by surface initiated photopolymerization in the presence of a cholesteric liquid crystal (CLC). The templated helical polymer (traversing 2/3 the cell thickness) was backfilled with an opposite handedness, photoresponsive CLC mixture yielding a photo-induced, large contrast, hyper-reflective (R > 99%) CLC film.