Passive energy‐conversion devices based on water uptake and evaporation offer a robust and cost‐effective alternative in a wide variety of applications. This work introduces a new research avenue in the design of passive devices by replacing traditional porous materials with rigid capillary layers engraved with optimized V‐shaped grooves. The concept is tested using aluminum sheets, which are machined by femtosecond laser and covered by silica or functionalized by oxygen plasma to achieve stable long‐term capillary properties. The durability of the proposed material is experimentally evaluated when functioning with aqueous salt concentrations: both the coated and functionalized specimens exhibit stable wettability after being immersed in saltwater for all the duration of the experiments (≈250 h in this work). The proposed new class of materials is envisaged for use in passive solar or thermal energy‐conversion devices. As a case study, a time‐discretized capillary model is coupled with a validated lumped‐parameters heat and mass transfer model, aiming to estimate the maximum size and productivity of a passive solar distiller employing porous materials of known thermal and capillary properties. This study paves the way to the use of a new class of rigid, highly thermally conductive materials that can significantly improve the performance of passive devices by simplifying the assembly of multistage setups, thus helping to extend their use to real‐scale applications.

Laser-induced graphene (LIG) has garnered tremendous attention in the past decade as a flexible, scalable, and patternable alternative for fabricating electronic sensors. Superhydrophobic and superhydrophilic variants of LIG have been demonstrated by previous studies. However, stability analysis of the superhydrophobic surface property has not been explored. In this study, we use an infrared nanosecond laser to fabricate reduced graphene oxide (rGO)-based strain sensor on a carbon fiber reinforced polymer (CFRP) composite substrate. The fabricated sensor is characterized to determine its gauge factor using a three-point bend test demonstrating a gauge factor of 40. The fabricated LIG exhibits excellent superhydrophobic properties with a high contact angle (>160°). Both superhydrophobicity and piezoresistivity of the LIG under water immersion are studied for 25 h, demonstrating high stability. The obtained results could be of interest to several sectors, especially for maritime and high humidity applications.

In scanning electron microscopy (SEM), a four quadrants backscattered electron detector (FQBSD) provides signals that can be combined to obtain a tridimensional reconstruction of the surface. The main challenge of the reconstruction operation consists of integrating the gradient field obtained as the normalized signal difference from each pair of opposite quadrants. Owing to the presence of electronic noise that eventually turns into image noise, a least square integration approach has been widely adopted for surface reconstruction. In the present work, we demonstrate the possibility of adopting regularization techniques (Tichonov's and Dirichlet's) to the surface reconstruction from FQBSD images to reduce the distortions due to sensitivity variations amongst the detector quadrants or an imprecise alignment of the FQBSD with the gun axis. This allows for a substantial improvement in the 3D surface reconstruction quality in terms of resolution and reduction of artifacts. These procedures have been experimentally validated on AISI 316L stainless steel polished surfaces with hardness indentation and on laser-patterned aluminum and silicon samples showing promising results.