Introducing Amine Functionalities on a Poly(3-hydroxybutyrate- co -3-hydroxyvalerate) Surface: Comparing the Use of Ammonia Plasma Treatment and Ethylenediamine Aminolysis

Nanotechnology and Biomaterials Centre and School of Molecular and Microbial Sciences, The University of Queensland, Brisbane, Queensland, Australia.
Biomacromolecules (Impact Factor: 5.75). 03/2006; 7(2):427-34. DOI: 10.1021/bm050497a
Source: PubMed


Amine functionalities were introduced onto the surface of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) films by applying radio frequency ammonia plasma treatment and wet ethylenediamine treatment. The modified surfaces were characterized by X-ray photoelectron spectroscopy (XPS) for chemical composition and Raman microspectroscopy for the spatial distribution of the chemical moieties. The relative amount of amine functionalities introduced onto the PHBV surface was determined by exposing the treated films to the vapor of trifluoromethylbenzaldehyde (TFBA) prior to XPS analysis. The highest amount of amino groups on the PHBV surface could be introduced by use of ammonia plasma at short treatment times of 5 and 10 s, but no effect of plasma power within the range of 2.5-20 W was observed. Ethylenediamine treatment yielded fewer surface amino groups, and in addition an increase in crystallinity as well as degradation of PHBV was evident from Fourier transform infrared spectroscopy. Raman maps showed that the coverage of amino groups on the PHBV surfaces was patchy with large areas having no amine functionalities.

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    • "Graphite felt electrodes were positioned in such a way that would allow exposure to the plasma of both sides of the sample. A previously described [34] [35], purpose-built plasma reactor was used. Briefly, it consisted of a tubular glass chamber with an external copper electrode wrapped around the central part. "
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    ABSTRACT: Surface modifications of electrode materials are important for improved performance of microbial bio-electrochemical systems. Here, we studied the effect of pre-treating both glassy carbon and graphite felt electrodes with either an oxygen or a nitrogen plasma before reactor inoculation with a mixed microbial consortia. The plasma produces chemical modifications at the electrode surface level. X-ray photoelectron spectroscopy and water contact angle analysis showed that the plasma removes surface contamination, produces ion implantation and renders the hydrophobic surfaces highly hydrophilic. Plasma pre-treatment considerably accelerated the generation of a bio-electrochemical anodic current after inoculation. Nitrogen plasma pre-treatment yielded the best performance, followed closely by oxygen plasma. Plasma pre-treated electrodes reached a plateau of maximum current density twice as fast as untreated electrodes. Analysis of the current development profiles suggests that the plasma pretreatment is neither producing a preferential attachment of certain types of bacteria over others nor accelerating the extracellular electron transfer rate. The results indicate that the plasma treatment considerably enhances the initial cell adhesion, which results in subsequently faster biofilm development. Plasma pre-treatment of electrodes is an inexpensive, fast, safe and straightforward technique to achieve more rapid start-up of bio-electrochemical processes.
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    • "Polyhydroxyalkanoates with functional groups (functionalized PHAs) have attracted increasing attention in the last ten years or so [1-9]. It has been generally recognized that important needs and markets exist for various types of functionalized PHAs as advanced materials in areas, such as tissue engineering [2,10,11], biocomposites [12], various medical applications [5,13], and polymers with tunable properties [6], only to name a few. "
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    • "The surface properties of biomaterials can be altered in such a way as to make them more adequate for biomedical applications. The most commonly used techniques are chemical etching, gas plasma treatment and electron beam radiation [33]. Among these techniques, plasma treatment is particularly versatile because the modification is restricted to the surface without compromising the material properties as a whole. "

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