# Knowledge base: Warsaw University of Technology

Back

## Plasma deposition of coatings with antimicrobial properties of organic polymer

#### Abstract

Introduction Films of organic materials are used in the packaging industry, in construction, electrical engineering, horticulture, orchards, and in medicine. Organic materials used as packaging for food products reduce the permeability of microorganisms and gases such as oxygen or water vapor, protecting them from rapid deterioration [1]. Air, moisture, microorganisms, temperature, light, cleanness of rooms and storage time have an impact on the quality of stored foods. Microorganisms acting on food include bacteria, molds and fungi. The largest group of microorganisms are bacteria, which create the greatest threat to food [2]. Nowadays, preservatives are widely used as food additives. Therefore, due to them it is possible to effectively prevent the unfavorable food spoilage, extend durability of raw materials, intermediate products and finished products as well as to prevent adverse changes during storage. The following chemical compounds are used as preservatives: sulfur dioxide, sulfites, benzoates, nitrites and many others [3]. In order to eliminate or reduce the level of preservatives in food, research is conducted to obtain active packaging, which were characterized by antimicrobial properties. Such packaging is achieved, inter alia, as a result of plasma modification of materials in order to apply on its surface substances inhibiting the growth of bacteria. The aim of this study was to characterize the properties of coatings for antimicrobial polyamide-polyethylene films. Results and discussion Deposition process was carried out for 1-10 minutes, using a PE-CVD (Plasma Enhanced Chemical Vapor Deposition) in PDBD barrier discharge, at atmospheric pressure. Coatings were precursors SO2 and Na2O. Coatings were obtained from mixtures of Ar + (0 - 1.4% SO2), 50% Ar + 50% (Ar + 0.7 - 1.4% SO2), Ar + (0 - 1.4% SO2) + Na2O and a mixture of Ar + Na2O, at earlier film surface plasma etching in argon. Sodium oxide was introduced to the reactor in the form of pairs of Na2O obtained by sublimation at: 300°C, 450°C, 530°C, 640°C. For modified films the following tests were performed: contact angle, water vapor permeability and bacteriological tests. During bacteriological studies, the degree of inhibition of Salmonella bacteria from a group of Gram (-) and that of Staphylococcus aureus from a group of Gram (+) were determined. For comparison, similar studies were carried out for plasma unmodified films - surface. 64 It was found that the plasma modification of contact angle decreased with respect to raw film by as much as half. No close relationship combining the hydrophilic properties of the antimicrobial properties was found. Water vapor permeability tests were aimed at checking whether the deposition process does not destroy the film. Deposited coatings improved the degree of film sealing towards water vapor permeability. Film barrier properties compared to that of the unmodified film have been improved even by 85%. The highest degree of inhibition of 16% for Salmonella and 8% for Staphylococcus aureus were obtained for films with a coating containing sulfur and deposited from mixtures of Ar + 0,1% SO2 and Ar + 0,7% SO2. Coatings deposited from a mixture of Ar + Na2O sublimed at 300°C exhibited, in relation to Salmonella, the degree of inhibition of up to 10%. Conclusions It was found that the films obtained by plasma modification, containing sulfur or sodium, exhibit better antimicrobial properties for the Salmonella of Gram (-) group than that for bacteria. Staphylococcus aureus with Gram (+) group. Plasma-deposited coatings have sealing properties against water vapor up to about 60%. Films obtained by this method can be used as packaging for food products.
Record ID
WUT551c9cb4662b43088eb13449e603033f
Diploma type
Master of Science
Author
Title in Polish
Plazmowe osadzanie powłok o właściwościach przeciwdrobnoustrojowych na tworzywach organicznych
Supervisor
Zenobia Rżanek-Boroch (FC/CChT) Zenobia Rżanek-Boroch,, Chair of Chemical Technology (FC/CChT)Faculty of Chemistry (FC)
Certifying unit
Faculty of Chemistry (FC)
Affiliation unit
Chair of Chemical Technology (FC/CChT)
Study subject / specialization
, Technologia Chemiczna
Language
(pl) Polish
Status
Finished
Defense Date
16-01-2012
Issue date (year)
2012
Keywords in Polish
-
Keywords in English
-
Abstract in Polish
urn:pw-repo:WUT551c9cb4662b43088eb13449e603033f