Laser‐modified nanostructures of PET films and cell behavior

Abstract

The surface of polyethylene terephthalate (PET) films was irradiated using KrF excimer laser (λ = 248 nm) with different number of pulses at constant repetition rate. The adhesion behavior of L-929 fibroblast cells on the irradiated surface was investigated. The changes in films' morphology were characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The hydrophilicity and both polar and dispersion components of the surface tension of the treated films were evaluated by contact angle and surface tension measurement techniques. The films roughness was evaluated by atomic force microscopy. AFM and SEM observations showed that a specific nanostructure was created on the laser-treated polyethylene terephthalate surface. Contact angle and surface energy measurements have indicated an increase in wettability of the laser treated samples up to 5 pulses as optimum result; while, by increasing the laser pulses beyond 5 pulses the hydrophilicity of laser treated samples dropped and the surface energy of the treated films was leveled off. Data from in vitro assays showed significant cell attachment and cell growth onto laser treated samples in comparison with the untreated films. Moreover, a number of fibroblast cells attached and proliferated onto treated PET films were achieved under optimum condition of 5 pulses which was significantly higher than the other treated samples.

Spatial Period of Laser-Induced Surface Nanoripples on PET Determines Escherichia coli Repellence

“…This is not the case for laser-structured PET surfaces using the laser parameters of the current study, which lead to significantly increased hydrophilic properties of the nanostructured surface (i.e., via Wenzel wetting or surface oxidation as discussed below). Similar effects of excimer laser treatment on the contact angle and chemical surface composition have been already described in literature [58][59][60]. While the water contact angle (CA) is about CA ~90 • for non-irradiated (flat) PET, it is reduced to CA ~60 • for PET covered with LIPSS processed at Φ = 5.7-6.2 mJ/cm 2 (data not shown here).…”

“…These alterations (e.g., changes of chemical composition, mechanical properties, hydrophilic/hydrophobic properties, etc.) are certainly different for polymer surfaces, like PET [58][59][60][61], and metal surfaces (steel, titanium, etc.) which have been used for most of the work on bacteria-repellent laserprocessed surfaces up to now.…”

The Flow Stress Behavior and Constitutive Model of Cr8Mo2SiV Tool Steel during Hot Deformation

“…[ 27 ] In particular, a constant creep exponent ( n ) of 5 and the activation energy of lattice self‐diffusion of metallic materials can be used as the activation energy ( Q ) of hot deformation to describe the peak stress in the classical hyperbolic sine equation. [ 26,28–31 ] Moreover, the deviation of creep exponent n from the theoretical value ( n = 5) can reflect the microstructure evolution. [ 32 ] The physical constitutive model with variable stress exponent can simply and effectively predict the flow behavior of metal materials due to its physical and metallurgical backgrounds.…”

Polystyrene surface modification using excimer laser and radio-frequency plasma: blood compatibility evaluations

“…Among these techniques which have been developed for this purpose, laser irradiation (Mirzadeh et al19932011Khorasani and Mirzadeh 2004bMirzadeh and Bagheri 2007) and plasma treatment (Chu 2007Mochizuki et al2011Solouk et al2011ab) can be applied to create new functional groups, micro- and nanostructures, and change in surface wettability.…”