This paper demonstrates that the addition of fluorinated block copolymers to PET solutions can be used to prepare PET films with controlled surface morphology, porosity and chemical composition, by exploiting the phenomenon known as breath figures (BF) formation during a spin-coating procedure. Surface features, such as number, depth and diameter of pores and chemical composition, can be tuned by varying the experimental conditions: relative humidity, solution composition and amount of the fluorinated block copolymer added to the PET solutions(in the range of 0.5 - 10 wt% with respect to PET). Breath figure patterns are more evident at relatively high concentrations of PET (3 wt%) and content of fluorinated block copolymer (10% with respect to PET). According to the obtained results, the fluorinated block copolymer seems to be involved in different steps of the mechanism of BF formation. XPS measurements showed a surface composition much more rich in fluorinated segments than expected from bulk composition. The combined surface roughness and surface segregation of fluorinated segments has only a limited effect on the macroscopic wettability of the surfaces.
Design of surface properties of PET films: effect of fluorinated block copolymers
FABBRI, PAOLA;MESSORI, MASSIMO;TOSELLI, MAURIZIO;
2007
Abstract
This paper demonstrates that the addition of fluorinated block copolymers to PET solutions can be used to prepare PET films with controlled surface morphology, porosity and chemical composition, by exploiting the phenomenon known as breath figures (BF) formation during a spin-coating procedure. Surface features, such as number, depth and diameter of pores and chemical composition, can be tuned by varying the experimental conditions: relative humidity, solution composition and amount of the fluorinated block copolymer added to the PET solutions(in the range of 0.5 - 10 wt% with respect to PET). Breath figure patterns are more evident at relatively high concentrations of PET (3 wt%) and content of fluorinated block copolymer (10% with respect to PET). According to the obtained results, the fluorinated block copolymer seems to be involved in different steps of the mechanism of BF formation. XPS measurements showed a surface composition much more rich in fluorinated segments than expected from bulk composition. The combined surface roughness and surface segregation of fluorinated segments has only a limited effect on the macroscopic wettability of the surfaces.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
