Functional surfaces for tribological applications: inspiration and design

Abstract

Surface texturing has been recognized as a method for enhancing the tribological properties of surfaces for many years. Adding a controlled texture to one of two faces in relative motion can have many positive effects, such as reduction of friction and wear and increase in load capacity. To date, the true potential of texturing has not been realized not because of the lack of enabling texturing technologies but because of the severe lack of detailed information about the mechanistic functional details of texturing in a tribological situation. Experimental as well as theoretical analysis of textured surfaces define important metrics for performance evaluation. These metrics represent the interaction between geometry of the texturing element and surface topology. To date, there is no agreement on the optimal values that should be implemented given a particular surface. More importantly, a well-defined methodology for the generation of deterministic textures of optimized designs virtually does not exist. Nature, on the other hand, offers many examples of efficient texturing strategies (geometries and topologies) specifically applied to mitigate frictional effects in a variety of situations. Studying these examples may advance the technology of surface engineering. This paper therefore, provides a comparative review of surface texturing that manifest viable synergy between tribology and biology. We attempt to provide successful emerging examples where borrowing from nature has inspired viable surface solutions that address difficult tribological problems both in dry and lubricated contact situations.

Multi-Scale Surface Texturing in Tribology—Current Knowledge and Future Perspectives

“…Historically, numerous methods have been utilized to create surface textures for tribological applications. In this context, surface textures can be defined as geometric features following a deterministic pattern, which is intended to be engineered to induce certain surface functionalities [40]. Moreover, textures can have a preferential direction or be arranged in a random fashion [40].…”

“…In this context, surface textures can be defined as geometric features following a deterministic pattern, which is intended to be engineered to induce certain surface functionalities [40]. Moreover, textures can have a preferential direction or be arranged in a random fashion [40]. The fabrication methods can be roughly divided into mechanical, chemical, physical, and thermal methods [41].…”

“…Accuracy is especially important for multi-scale textures since textures have to be combined suitably and both patterns should be left intact during the texturing process. For patterned surfaces in general and particularly for multi-scale surfaces, the real area of contact and hence the resulting friction force is significantly influenced by the arrangement of the textural features [40]. Efficiency is a critical factor when thinking about large-scale production.…”

“…In the literature, several review papers can be found summarizing methods to create surface textures for tribological applications [40][41][42]. Hence, here only techniques with a special connection to multi-scale surface texturing will be presented.…”

Functionalization of Plastic Parts by Replication of Variable Pitch Laser-Induced Periodic Surface Structures

“…Surface functionalization has emerged as a solution to the needs of various stakeholders. Functional surfaces find application as self-cleaning [2][3][4], scaffolds [5,6], tissues [7][8][9], optical parts [10], anti-icing [11,12], in friction reduction [13,14], and in engineering of injection mold surfaces [15]. All these applications generated an increasing demand to develop reliable and cost-effective mass manufacturing technologies for polymer surface replication.…”