Surface properties of polymers treated with F₂ laser

Abstract

a Selected polymers (polyethylene-PE, polypropylene-PP, polytetrafluoroethylene-PTFE, polystyrene-PS and polyethylenterephthalate-PET) were irradiated with the linearly polarized light of a pulsed 157 nm F 2 laser. The irradiation results in degradation of polymers and ablation of polymer surfaces. Contact angle, measured by goniometry, was studied as a function of the number of laser pulses. The volume of the ablated polymer layer was determined by gravimetry. Changes in surface morphology and roughness were observed using atomic force microscopy. Surface chemistry of the samples was investigated by electrokinetic analysis and by XPS. While PET and PE exhibit small ablation, the ablation of PS and PTFE is more significant, and the most pronounced ablation is observed on PP. Contact angle of all polymers, with the only exception of PP, is a decreasing function of the number of laser pulses up to 2000 pulses. Laser irradiation leads to a refinement of the polymer surface morphology and a decrease of their surface roughness. Electrokinetic analysis and PS show changes in the surface chemistry of polymers after the laser treatment.

Electrokinetic Potential and Other Surface Properties of Polymer Foils and Their Modifications

“…5, left) in comparison with that observed on the same polymers treated in plasma discharge (Fig. 5, right) [12,53]. Figure 5.…”

“…The wettability increase is caused by creation of polar groups, exhibiting enhanced hydrophilicity, at the polymer surface [12]. The similar effect on surface properties has also the laser irradiation [53]. Fig.…”

“…Empty columns are pristine polymers (only at PET), full columns treated ones Figure 6. Contact angle on surface of selected polymer foils after plasma (left, [12]) or laser (right, [53]) treatment determined by goniometry Plasma treatment or laser irradiation result in a dramatic decline of the contact angle and corresponding increase of polymer wettability as it shown in Fig. 6.…”

“…chains and bonds scission, ablation, oxidation and cross-linking) and creation of polar groups [12]. The effect of laser irradiation is not too strong due to that this treatment way influences surface chemistry and surface properties more weak [12,53]. Even in some causes zeta potential decreases after laser irradiation.…”

“…Figure 5. Concentration of oxygen groups on surface of selected polymer foils after plasma (left, [12]) or laser (right, [53]) treatment determined by XPS. Empty columns are pristine polymers (only at PET), full columns treated ones Figure 6.…”