Introduction: The surface modification of hydrophobic polymers (polyamide 12, PA12) offers a method to increase the hydrophilicity of the surfaces of polymeric medical devices. Plasma is a suitable technology but unfortunately, the modification is reversible, and the hydrophilicity decreases in short time. Otherwise, surface modification with photo-reactive chromophores, namely phenyl azide (PhAz), offers an alternative and irreversible method for the surface hydrophilization. Methods: The aim of the present work was to combine plasma technology and the azide’s photo-reaction to increase the PA12 hydrophilicity. In the first process step, the polymer surface was activated using plasma reaction. Afterwards, a solution of PhAz was sprayed on the activated polymer surface. Finally, the samples were treated with ultraviolet light to trigger the chemical reaction between the polymer chemical groups and PhAz. Results: Untreated, plasma-treated, and photo-modified polymers were compared in terms of wettability by means of the contact angle (CA) measurements (immediately, 1 week and a month from the reaction). The hydrophilicity increase of treated surfaces was estimated through “deltaCA”, the decreasing of CA compared to the untreated polymer. Plasma-treated samples were initially very hydrophilic, but hydrophilicity was significantly reduced after 1 week and almost completely lost after 1 month. PhAz-treated samples were significantly more hydrophilic if compared with untreated polymer and after 1-month deltaCA was unchanged. The samples produced by plasma activation followed by treatment with PhAz were very hydrophilic. Some hydrophilicity reduction occurred over time, but after 1 month “deltaCA” was stabilized and still considerably high. Conclusions: The plasma-based pre-activation process was able to improve the PhAz surface process modification of PA12. Conceivably, new chemical groups generated by the plasma reaction can react with PhAz chromophores and increase the yield of the photochemical reaction, making the polymer surface more hydrophilic if compared with the other processes.
Photochemical Modification of a Medical Grade Polyamide Using a Plasma-Based Pre-Treatment
D'ONOFRIO, SIMONE
;Bignotti F.
2018-01-01
Abstract
Introduction: The surface modification of hydrophobic polymers (polyamide 12, PA12) offers a method to increase the hydrophilicity of the surfaces of polymeric medical devices. Plasma is a suitable technology but unfortunately, the modification is reversible, and the hydrophilicity decreases in short time. Otherwise, surface modification with photo-reactive chromophores, namely phenyl azide (PhAz), offers an alternative and irreversible method for the surface hydrophilization. Methods: The aim of the present work was to combine plasma technology and the azide’s photo-reaction to increase the PA12 hydrophilicity. In the first process step, the polymer surface was activated using plasma reaction. Afterwards, a solution of PhAz was sprayed on the activated polymer surface. Finally, the samples were treated with ultraviolet light to trigger the chemical reaction between the polymer chemical groups and PhAz. Results: Untreated, plasma-treated, and photo-modified polymers were compared in terms of wettability by means of the contact angle (CA) measurements (immediately, 1 week and a month from the reaction). The hydrophilicity increase of treated surfaces was estimated through “deltaCA”, the decreasing of CA compared to the untreated polymer. Plasma-treated samples were initially very hydrophilic, but hydrophilicity was significantly reduced after 1 week and almost completely lost after 1 month. PhAz-treated samples were significantly more hydrophilic if compared with untreated polymer and after 1-month deltaCA was unchanged. The samples produced by plasma activation followed by treatment with PhAz were very hydrophilic. Some hydrophilicity reduction occurred over time, but after 1 month “deltaCA” was stabilized and still considerably high. Conclusions: The plasma-based pre-activation process was able to improve the PhAz surface process modification of PA12. Conceivably, new chemical groups generated by the plasma reaction can react with PhAz chromophores and increase the yield of the photochemical reaction, making the polymer surface more hydrophilic if compared with the other processes.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
