Degradable Poly(ethylene oxide)-Like Plasma Polymer Films Used for the Controlled Release of Nisin

Abstract

Poly(ethylene oxide) (PEO)-like thin films were successfully prepared by plasma-assisted vapor thermal deposition (PAVTD). PEO powders with a molar weight (Mw) between 1500 g/mol and 600,000 g/mol were used as bulk precursors. The effect of Mw on the structural and surface properties was analyzed for PEO films prepared at a lower plasma power. Fourier transform (FTIR-ATR) spectroscopy showed that the molecular structure was well preserved regardless of the Mw of the precursors. The stronger impact of the process conditions (the presence/absence of plasma) was proved. Molecular weight polydispersity, as well as wettability, increased in the samples prepared at 5 W. The influence of deposition plasma power (0–30 W) on solubility and permeation properties was evaluated for a bulk precursor of Mw 1500 g/mol. The rate of thickness loss after immersion in water was found to be tunable in this way, with the films prepared at the highest plasma power showing higher stability. The effect of plasma power deposition conditions was also shown during the permeability study. Prepared PEO films were used as a cover, and permeation layers for biologically active nisin molecule and a controlled release of this bacteriocin into water was achieved.

Structure of Plasma (re)Polymerized Polylactic Acid Films Fabricated by Plasma-Assisted Vapour Thermal Deposition

“…CO 2 or CO species may be subsequently released from the created end groups. Importance of such process (especially the release of CO) was suggested by the process data on such a diverse set of experiments like magnetron sputtering of polyimide [ 22 ] or nylon [ 39 ], PAVTD of polyimide [ 18 ] or poly(ethylene oxide) [ 20 , 23 ]. These gases were also the most volatile species observed during purely thermal degradation of PLA [ 40 ], so these reactions shall be relevant qualitatively also to formation of the PAVTD films prepared without plasma power (0 W).…”

“…This, in turn, restrains the attainable structures of plasma polymers synthesised by the PECVD technique. To overcome this general limitation, plasma-assisted vapour (vacuum) thermal deposition (decomposition/degradation) (PAVTD) was introduced as an alternative route of production of plasma polymers [ 18 , 19 , 20 , 21 , 22 , 23 ]. In this technique, the polymer is heated at reduced pressure in an inert atmosphere to a temperature at which the thermal decomposition of its macromolecular chains occurs.…”

“…This generates a flux of both low- and high-molar mass species that are subsequently activated or fragmented by the plasma that initiates the polymerisation process. As was shown, e.g., by analyses of molar mass, swelling and composition, the final structure of such produced coatings may be tuned simply by the applied power from highly crosslinked one for high applied powers to the structure with partial preservation of the polymer chains present in the initial polymer at low powers [ 19 , 21 , 23 , 24 , 25 ]. In other words, this technique allows for the filling of the gap between the fully aperiodic plasma polymers synthesised by PECVD and polymers prepared by classic wet chemistry and thus to widen further the range of achievable functional properties of plasma polymers.…”

Thin films of cross-linked polylactic acid as tailored platforms for controlled drug release

“…Compared to the PECVD technique, the PAVTD offers an attractive way to supply both low-and highmolecular-weight species to the gas phase. Such polydisperse species are then plasma-activated with the bond cleavage and radical formation, and undergo re-polymerization processes when deposited onto substrates [39][40][41][42][43][44][45][46][47][48]. An advantage of this method is that the structural properties can be easily controlled via the applied discharge power.…”

Surface Chemistry of Polymers

“…Non-equilibrium gaseous plasma, however, could also be used as a medium for deposition of various coatings. Kousal et al [ 7 ] used low-power gaseous plasma for depositing thin polymer films on different substrates. Polyethylene oxide (PEO) of various molecular weights was mounted into the reaction chamber.…”