The addition of extra-polymeric components in excessive
amounts can result, in a heterogeneous film structure with discontinuities
and irregularities. However, these components at
appropriate levels can favor the polymeric matrix and increase the
interaction between the polymer and the added component
(Ahmad et al., 2012; Gemili, Yemenicioglu, & Altinkaya, 2009; Melo
et al., 2012; Ramos, Jimenez, Peltzer, & Garrigos, 2012 ). MajdzadehArdakani,
Navarchian, and Sadeghi (2010) evaluated the method of
‘casting’ in starch-based biopolymer films with added clays and
concluded that the mechanical properties of the films are strongly
influenced by the type of clay and the stirring mode used in the
process. Mechanical combined with ultrasonic stirring favored the
dispersion of clays in the film and this led to an increase in the
elasticity modulus of the nanocomposites.
With respect to the puncture test, the mean of treatments
related to puncture strength showed no significant effect (p > 0.05)
between control and treatments. The results are shown in Table 3.
3.4. Atomic force microscopy (AFM)
Photomicrographs obtained by atomic force microscopy allowed
us to evaluate the microtopography of the surface of the films in
two and three dimensions (Figs. 4 and 5).
From 3D figures we can see that the films containing the mix of
bacteriophages have a more irregular and porous surface. In 2D
figures it was observed that pore irregularity formed in the darker