Influence of laser irradiation on the thin collagen films.
Part I. Mechanism of "micro-foam” structure formation and collagen surface ablation
Polimery 2007, No 4, 259
Thin collagen films were subjected to KrF excimer laser irradiation (λ= 248nm). The effect of irradiation on the film surface was evaluated using scanning electron microscopy (SEM) (Fig. 1-6) and atomic force microscopy (AFM) (Fig. 8, 9). Material weight loss, as a result of ablative process, was determined using quartz crystal microbalance (QCM method) (Table 1). Laser irradiation of dried collagen films (15% of residual water) caused "foaming” of the surface just after use of one pulse. The mechanism of "micro-foam” formation based on the nucleation and growth of the bubbles, possible as aresult of pressure drop causing tensile stress exceeding the strength of collagen film (Fig. 7), was discussed. This phenomenon is caused by bipolar pressure wave formed due to the surface "acceleration-deceleration” sequence towards the laser beam direction.
Key words: collagen films, laser irradiation, photomechanical ablation, structure of „micro-foam”
M. Wiśniewski, A. Sionkowska, H. Kaczmarek, S. Lazare, V. Tokarev
Influence of laser irradiation on the thin collagen films. Part I. Mechanism of "micro-foam” structure formation and collagen surface ablation