Lattice metamaterials are a class of engineered materials with repeating 3D structures (lattices) at the macroscale, microscale or nanoscale, designed to achieve mechanical, thermal, acoustic, or electromagnetic properties not found in naturally occurring materials. Their behaviour is governed more by structure (geometry) than composition. The lattice structures enable us to produce tailorable multifunctional properties, including mechanical, thermal, acoustic, vibration, and electromagnetic properties.  There are several key mechanical properties, which are the focus of this study of lattice metamaterials - high strength-to-weight ratio, programmable stiffness and compliance, negative Poisson's ratio, high energy absorption, etc. Some lattices even combine mechanical load-bearing ability with functionalities like heat management, sensing, or actuation. The ability to blend a range of properties makes these materials ideal for various applications, such as aerospace, transport, automotive, marine, biomedical and sports.

In this work, the main aim is to design and fabricate different metallic lattice materials at the macroscale using the Laser Powder Bed Fusion (LPBF process), with the objective of obtaining different types of mechanical properties, considering both strut and surface-based lattices. 

First, the design of conformal lattice structures to encompass complex, three-dimensional geometry was addressed through a comprehensive review and subsequent development of a systematic design process that establishes a step-by-step procedure incorporating lattice geometry and topology generation, as well as compatibility with lattice types and structural boundary integration [1] . 

Next, the focus was on strut-based cellular metamaterial architectures [2], acquiring low-density and high-strength metallic metamaterials. These titanium (Ti-6Al-4V) lattices were designed imitating Wolff’s law of bone remodelling that led to lattice configurations with an exceptional strength-to-density ratio, compared to conventional cellular metamaterials. This was followed by hollow-strut titanium lattice materials, whereby it was found that hollow-strut Ti-6Al-4V lattice materials exhibit consistently higher strength and stiffness (by as much as 60%) compared to solid-strut counterparts of the same relative density [3].

In summary, it was shown that a conformal lattice design founded on either strut-based (cellular) or surface-based (TPMS) lattices, along with the complex geometry mapping capability, can generate highly tailored mechanical properties for a variety of engineering applications, thus revolutionising next-generation optimised designs with exceptional operational performance and structural integrity.

“Recyclable-by-design” is an eco-design strategy aimed at promoting closed-loop material recovery at the end of a product’s life cycle ¹. This approach represents a state-of-the-art technological solution to the challenges of sustainable polymer recycling and addresses the socio-economic impact of plastic pollution. In this study, we adopted a recyclable-by-design strategy to re-engineer polyurethane polymers and facilitate their end-of-life recyclability.

The covalent adaptable networks (CANs) are polymers with dynamic covalent bonds (DCBs), extensively used as structural materials in composite, coating, adhesive, and sealant applications ². DCBs in these networks offer intrinsic reversibility while maintaining the robustness of covalent bonds, allowing the formation of mechanically stable polymers that respond to external stimuli ³.

In this study, we first synthesized a novel diol monomer incorporating an acylhydrazone linkage, which was then used to produce a thermoset polyurethane in combination with a trimer isocyanate. The resulting polymer demonstrated the ability to depolymerize under mildly acidic conditions at room temperature, indicating reversible behavior. The polyurethane films exhibited a range of desirable properties, including strong mechanical integrity (maximum tensile strength of 28.07 MPa), excellent solvent resistance, and thermal stability—qualities that make them well-suited for high-performance applications. Notably, the dynamic polyurethane showed controlled degradation in the presence of acetone and acetic acid, with recyclability demonstrated across three cycles. The recycled self-standing films retained mechanical performance comparable to a non-dynamic control polymer, although a gradual decline in tensile strength was observed over repeated cycles.

In addition, the polyurethane films exhibited self-healing properties, repairing surface cuts under mild conditions. Coating adhesion and pencil hardness tests also yielded promising results, highlighting the potential of this material for use in protective and functional coatings.

3D Concrete Printing (3DCP) has emerged as a disruptive additive‑manufacturing technology that redefines on‑site concrete fabrication. By depositing material layer by layer directly from digital models, 3DCP eliminates conventional formwork, reduces labor requirements and material waste, and enables unprecedented geometric freedom [1]. Large‑scale demonstrations have validated the production of complex free‑form structures without auxiliary supports, highlighting the potential for novel architectural expressions [2].

Despite these advances, interlayer bonding remains a critical technical challenge. The time lapse between successive depositions creates so‑called “cold joints,” which can compromise interface strength if the underlying layer gains excessive stiffness. Empirical studies demonstrate that deposition interval, surface moisture and mix rheology are decisive factors governing interlayer adhesion [3]. To address this, researchers have optimized mixture designs—balancing extrudability and early‑age buildability via tailored admixtures and fibre reinforcement—and developed thixotropic‑based models to prescribe deposition rates that ensure each layer can reliably support the next [4][5].

Integrating conventional reinforcement into 3D‑printed elements poses another hurdle. While embedding steel bars remains cumbersome, alternative strategies—such as interlocking layer geometries or in‑situ mineralization at interfaces—have shown promising improvements in shear strength and cold‑joint “healing” [6]. Meanwhile, the absence of dedicated standards for layered, extrusion‑printed concrete creates regulatory uncertainty regarding anisotropic mechanical properties, long‑term durability and appropriate testing protocols. Nonetheless, pilot projects—from pedestrian bridges to residential buildings—are proceeding under experimental approvals, paving the regulatory path forward [7].

Sustainability considerations further motivate 3DCP development. By deploying material only where structurally and architecturally necessary—and eliminating formwork—waste reductions of up to 60 % and labor‑cost savings approaching 50 % have been reported. Moreover, compatibility with low‑clinker cements and geopolymers suggests possible lifecycle‑carbon reductions of 70–90 %, provided such mixes maintain printability and adequate performance [1][8].

The "green industrialization" of surface treatments involves the search for new technologies and processes as alternative tribological coatings produce by electrodeposited. Technologies like Diamond-like carbon (DLC) coatings aimed at reducing friction many developments were done to improve the mechanical properties but with some limitations. The hybrid technologies we are developing provide new opportunities for enhancing the protection and durability of heavily stressed mechanisms that require multifunctional properties, all while maintaining energy efficiency.The hybrid process studied consists of the association of PVD and PeCVD coating process to improve tribological and corrosion resistance properties by integrating hard layers for abrasion resistance and low friction layers.

The hybrid process we are investigating combines Physical Vapor Deposition (PVD) and Plasma-Enhanced Chemical Vapor Deposition (PeCVD) coating techniques. This approach improves tribological and corrosion resistance properties by integrating hard layers with self-lubricating particles, ensuring enhanced performance and longevity

Hybrid technologies we are developing offers new perspectives for protection and durability for heavily stressed mechanisms requiring multifunctional properties, while being energy efficient.