Nanodiamond-Polymer Composites for Decreased Laser Ablation Thresholds

During the past decade, nanodiamonds were demonstrated to be an environmentally friendly, easy-to-handle, accessible additive for polymer science, which also offers sensory-relevant properties. Therefore, nanodiamond-based composites are promising substrates for medical applications, heat transfer materials in electronic devices, or three-dimensional (3D) materials for sensor applications within various fields related to automotive, sensory, and printing applications. One key factor for the implementation of composite materials in modern devices is the precise and energy-efficient structuring of the material. Herein, laser ablation-induced structuring using pulsed laser systems is one of the most applied approaches to achieve micro- and nanostructure surfaces. In this work, nanodiamond additives were demonstrated to have a significant beneficial impact on the laser ablation performance of nanodiamond acrylate composites, in particular, on the laser ablation threshold and the incubation effect. Furthermore, we show that surface modification using the surface graphite content is a crucial parameter for the ablation. Employing a controlled surface graphitization of the nanodiamonds, their optical properties and interaction with the polymer can be influenced to improve the laser ablation performance of composites. In comparison to pure sp2 carbon additives like graphene oxide, graphitized nanodiamond composites exhibit higher optical density and diffuse light scattering properties. These properties lead to a more surface-located light-induced energy input. The investigations of the laser ablation spot also allowed first insight into the mechanism of the ablation, where the surface graphite of the nanodiamond also influences the bonding strength of the nanodiamond (ND) to the acrylate system. This supports thermal and mechanical ablation and, thus, a decrease of the laser ablation threshold energy. Our results demonstrate that nanodiamond composites are promising materials for laser structuring processing. Further improvement of the diamond surface might even improve their applicability.