## 3 Results and Discussion  
### Fabrication of Microstructure Textures  
In order to solve the problem of abnormal wear on bearing linings at low speeds, heavy loads, and frequent start and stop conditions, and to improve the tribological performance and lubrication characteristics of the bearings, a regular microstripe texture was constructed on the surface of water-lubricated materials. The dimensions of the microtextures were the following: the spacing L between two adjacent stripes was 5 \(\upmu\)m, and the depth H of the stripes was 0.5 \(\upmu\)m. The direction of the stripe microtexture was aligned perpendicular to the direction of motion of the copper ring, as shown in Figure 4. The design of the microtexture was inspired by the microstructure of the epidermal scales of a lizard called sandfish (_Scincus scincus_). The dimensions of the microtexture (L and H) were based on the scale parameters of the lizard's epidermal scale microstructure. Figure 4: The schematic diagram of cross-section of microstripe texture. The microstripe texture was fabricated onto the surface of the water-lubricated material by a hot-embossing method. The water-lubricated blocks were placed into the mold container, and the mold was then placed into the precision hot-pressing machine. Specific temperatures and pressures were applied to the mold according to the thermoplastic characteristics of the Thordon and polyurethane. After a certain forming time, Thordon and polyurethane samples featuring imprinted microstripe textures or pristine surfaces were obtained. All the samples were finally cleaned with acetone to remove residual material, dust, or other contaminants in preparation for tribological testing. Table 1 summarizes the forming temperatures, pressures, and times for embossing the microstripe textures on the Thordon and polyurethane materials. The parameters for each material varied depending on their different thermoforming properties. Due to the poor fluidity of the thermoplastic polyurethane, it was not possible for the flow to spread evenly over a short period of time and it also could not overflow in time, resulting in the microstripe texture not being effectively embossed onto the surface of the material. Therefore, an extended pressing time for the polyurethane, as opposed to the Thordon material, allowed the melt to be fully fluidized and spread out so that the microtexture of the mold was fully embossed onto the surface of the material. The pictures of the Thordon and polyurethane blocks after hot embossing are shown in Figure 5a,d. The topography of the Thordon and polyurethane samples was characterized by laser microscopy, and the results are shown in Figure 5b,e. Comparing the surface topographies of the samples, regular microstripe were successfully fabricated onto the surfaces of the Thordon and polyurethane materials by the hot-embossing technique. Figure 5c,f show the surface profile curves of the samples truncated by the red dashed lines in Figure 5b,e, respectively. It can be seen that the profile curves of the pristine surfaces show irregular bumps or pits, representing random micro-convex bodies and micro-pits that occur on the sample surfaces, whereas the profile curves passing through the microtextured surfaces reveal regular jagged shapes, indicating regular microstripes. The spacing between two neighboring stripes was about 5 um, and the depth of the stripe monomer was about 0.5 um. The results demonstrate that the microstripe texture was successfully fabricated on the surfaces of the Thordon and polyurethane materials by the hot-embossing technique. Table 2 summarised the surface roughness (Sa) of Thordon and PU with pristine and microtextured surfaces. By comparing the roughness of the material surface, we found an interesting phenomenon that the roughness of the microtextured surface was lower than that of the pristine surface.