Plasma treatment PHAs modification

Apart from modifications in the bulk, also surface modification of PHAs has been reported. Poly(3HB-co-3HV) film surfaces have been subjected to plasma treatments, using various (mixtures of) gases, water or allyl alcohol [112-114]. Compared to the non-treated polymer samples, the wettability of the surface modified poly(3HB-co-3HV) was increased significantly [112-114]. This yielded a material with improved biocompatibility, which is imperative in the development of biomedical devices. 

The section on the chemical modification of PHAs is divided into different topics such as carhoxylation, hydroxylation, epoxidation, halogenations and graft copolymerization. The section on the physical modification of PHAs is divided into different topics such as PHA blending and coating, PHA irradiation, ion implantation, plasma treatment, electrospinning. To conclude, the authors discuss the modification of PHAs with enzymes. 

The surface modification of PHAs was performed by either a direct treatment (plasma, NaOH, enzyme) or by coating. Among the direct surface treatments, the use of plasma was by far the most popular until now. " However, in any cases of plasma, lipase" or NaOH treatment, the results were similar enhancement of hydrophilicity with the concomitant improvement of biocompatibility. The only drawback was noticed in the case of NaOH treatment and concerned the aging effect, with the hydrophilicity decreasing with time. ... 

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