Poly(vinyl chloride) Coupling with UV Laser Radiation: Comparison between Polymer Absorbers and Nanoparticles to Increase Efficiency for Laser Ablation Propulsion

Among the wide variety of applications of polymers, their use as targets for laser ablation propulsion has recently gained interest. Poly(vinyl chloride) (PVC) showed promising propulsion properties that can be related to its well-defined thermal decomposition path. However, strategies are needed to increase the momentum generation efficiency with laser radiation. To increase the energetic efficiency in the laser generation of a mechanical impulse, optical and thermodynamic properties must be properly tuned so that the ablation threshold fluence (Fth) is reduced. In this work, we compare two strategies to increase the optical absorption of PVC in the UV region. One is based on embedding carbon nanoparticles (CNPs) in the PVC matrix, whereas the other relies on mixing PVC with poly(styrene sulfonate) acting as a chromophore. Uniform polymer films of 50 μm thickness are fabricated using a multilayer spin-coating technique. Samples are then tested by measuring the laser-generated impulse using a ballistic pendulum under the fluence range from 0.2 to 3 J/cm2 and values of Fth are extracted. These results are discussed from the point of view of optical and thermodynamic properties of the modified PVC, concluding that the localized optical absorption given by CNP is the most efficient strategy in the optical-to-mechanical energy conversion via laser-induced ablation of the polymer film.