3D printing technology has been making waves in various industries, and now it's taking on a new challenge: creating materials that can resist fungal growth while also providing vibration isolation. Researchers from Jiangnan University and Jiangda Vibration Isolator Co., Ltd. have developed a 3D-printed silicone rubber lattice that not only fights off fungi but also absorbs vibrations and withstands repeated compression in marine environments. This innovative material is a game-changer for shipborne equipment and other systems exposed to humidity, temperature variations, and persistent vibrations.
The key to this breakthrough lies in the careful formulation of a printable composite ink using silicone rubber and hexagonal boron nitride (hBN). By controlling the composition and internal geometry through additive manufacturing, the researchers were able to create a lattice with ordered filaments and stable interlayer bonding. The processing limit of 1-5 wt% hBN in the ink ensures both printability and antifungal performance, striking a delicate balance that is often challenging to achieve.
In antifungal testing, the hBN-filled lattice demonstrated impressive results. It inhibited fungal growth more effectively as the filler content increased, with a 5 wt% hBN concentration achieving a fungal growth rating of 0, indicating no observable fungal growth. The lattice's architecture also played a crucial role, as larger filament spacing increased fungal coverage, especially at lower filler loadings. This finding highlights the importance of design considerations in achieving optimal antifungal performance.
The antifungal properties of the lattice can be attributed to two main factors. Firstly, hBN increased surface hydrophobicity, making the material more water-repellent and reducing fungal spore penetration. Secondly, microscopy data revealed biochemical and physical damage at the fungus-material interface, with the presence of reactive oxygen species and disrupted hyphal surfaces. This dual mechanism of hydrophobic barrier and direct antifungal activity through oxidative stress and cell-wall damage is a significant contribution to the field.
Beyond antifungal resistance, the lattice also excels in vibration isolation. Mechanical testing showed that the lattice architecture functions as a cushioning structure, absorbing energy through elastic buckling in the ordered lattice cells. Finite element simulations and in situ observations supported this mechanism, and the lattice retained its durability under repeated loading, with no structural defects observed after 10,000 compression-release cycles.
Vibration tests further showcased the lattice's effectiveness in vibration isolation. Introducing the lattice shifted the isolation frequency leftward, widening the effective vibration-isolation range. Random vibration tests produced direction-dependent results, with isolation efficiencies above 80% across all three directions tested. Even after exposure to fungi in a carbon-rich medium, the vibration-isolation performance remained largely unchanged.
This groundbreaking research, titled "Antifungal and cushioning elastomer lattices via additive manufacturing," combines antifungal protection and mechanical performance in a single printed structure. By addressing the trade-off between fungal resistance and flexibility, the researchers have opened up new possibilities for shipborne equipment and other applications exposed to harsh environmental conditions. The potential implications are far-reaching, and the 3D printing industry is poised to play a pivotal role in shaping the future of additive manufacturing.
