Nanocomposites and nanomaterials

Dopant concentration effect on fungi resistant of nonlinear polymer nanocomposites
Voronkin A.A.1, Mishurov D.O.1,2, Nedilko O.P.
1 National Technical University «Kharkiv Polytechnic Institute» , Kyrpychova str., 2, 61002, Kharkiv, Ukraine 
E-mail: andriivoronkin@gmail.com
2 Institute of Chemistry at V.N. Karazin Kharkiv National University, Svoboda sqr., 4, 61022, Kharkiv, Ukraine
3V.N. Karazin Kharkiv National University, Svoboda sqr., 4, 61022, Kharkiv, Ukraine

Many factors influence on NLO polymer composites functional properties in process their exploitation. One of main factor that negative effect on functional properties of NLO polymer composites is growth of mold fungi on their surfaces. Therefore, important problem of NLO polymer materials is fungal resistance. Investigated polymer composites are doped with flavonoids that are natural antiseptics. Thus, maybe that concentration changing of dopant in polymer matrix can an influence on growth inhibition of the mold fungi on ones surfaces. 
Thus, the purpose of this work is the investigation influence of dopant concentration on the fungal resistance of thin polymer films based on an epoxy polymer (EP) doped of flavone type chromophores such as 3,5,7,3/,4/-pentahydroxyflavone (Q), 3,5,7,3/,4/-pentahydroxiflavone- 8-sulfonic acid (SQ) and 3,7,3/,4/-tetrahydroxyflavone (F). As the mold fungi Aspergillus niger (A) and Penicillium chrysogenum (P) were used. Undoped epoxy matrix was used as a reference samples (ref).
Fungistatic effect on doped polymer films with a chromophores concentration of 30 wt. % and 50 wt. % were determined by ISO 846-1997 (method b). Growth area of mold fungi was calculated in ImageJ program. 
The investigation carried out is shown that increasing dopant concentration from 30 wt. % till 50 wt. % leads to the growth inhibition of mold fungi on the polymer composite films surface. In case mold fungum A, the growth area decreased from 60% to 17% for all dopants. In case of mold fungum P from 70% to 43% relative to the reference samples. The all polymer composites are estimated to 1-2 points according to scale listed at ISO 846-1997 (fungistatic effect). This fact can be explained by the fact that the given dopants are natural antiseptics and increasing them concentration leads to increase fungistatic effect. Thus, it may the conclusions that polymer composites with dopant concentration about 30-50 wt. % can effectively use in various NLO applications of photonics and optoelectronics.