Surface Roughness of Wood Substrates after Grinding and Its Influence on the Modification Effect of Structural Color Layers

Abstract

For a comprehensive understanding of the surface roughness of wood substrates after grinding and its influence on the construction of surface structural color layers (SCLs) and the effect of color production, four typical diffuse-porous wood species were investigated by grinding with abrasive belts of different grits. The results indicated that an abrasive belt of suitable grit was required to form the flattest surface for different wood species. Notably, 400-grit abrasive belts can be used for quaking aspen (QA) and yellow poplar (YP) wood, while 320-grit abrasive belts can be used for kang duan (KD) and hard maple (HM) wood for the grinding process. When the grit of the belt was 80–240, the surface roughness of the wood was high, and the gully contour was mainly determined by the machining marks created by the grits during the cutting process. When the SCLs were constructed on these wood samples, the grooves formed by grit grinding caused the emulsion to overflow on the surface of the wood, thus preventing the formation of well-ordered SCLs with excellent color production. In contrast, when the grit of the abrasive belts was increased to the range of 320–800, the main factors affecting the roughness of the wood surface led to the anatomical structural features. Vessels, in particular, not only affected the surface roughness of the wood but also served as a major path for emulsion flow. The number, diameter, and patency of vessels per unit area were the main factors affecting the SCL’s construction and decoration effect on wood surfaces. This study clarifies that the roughness of the wood surface after the grinding process is jointly influenced by the grit of the abrasive belt and the wood’s anatomical structure. Roughness is an essential factor that affects the modification effect of the SCLs on the surface of wood.

Study of Selective Modification Effect of Constructed Structural Color Layers on EUROPEAN Beech Wood Surfaces

“…It can be seen from Figure 8B that, compared with other diffuse porous woods such as aspen and hard maple [31], the wide rays of beech wood were its typical anatomical structure. From the three-section micrographs of beech, it could be seen that the rays, es- When the fourth and fifth brushings were performed, the reflection curve continued overall toward a higher reflectance for the structural color layer of the tangential section of the wood, with the peak reflectance at 501 nm of 92.4% and 96.5% (T-4 and T-5 in Figure 7), respectively, which had gentler slopes of the peak shape relative to the structural color layer constructed in the second and third brushings.…”

“…In addition to the ray tissue, it was widely distributed with vessels which had a much larger inner diameter than the ray cells. In previous studies, it was found that the roughness of the wood surface would affect the formation of ordered structures by microspheres [31]. Therefore, the ray region provided excellent substrate flatness for the structural color layer construction, while the microstructure of other areas mainly composed of vessels and wood fibers was more uneven, which was not conducive to the self-assembly of microspheres into well-ordered structures.…”

“…However, it is still important to note that the wood sample used to observe the anatomy in the SEM was cut with a sharp blade to obtain a good cu ing surface. However, before brushing the finishing layer, the radial or tangential section of the wood needed to be sawed and sanded, and these treatments produced cu ing and ploughing on the wood surface [38], which also made it impossible to clearly distinguish the microscopic anatomical features, such as ray tissue, through It can be seen from Figure 8B that, compared with other diffuse porous woods such as aspen and hard maple [31], the wide rays of beech wood were its typical anatomical structure. From the three-section micrographs of beech, it could be seen that the rays, especially the wide rays, were made up of closely fitting ray cells of similar shape.…”

“…In our preliminary research, the selected wood species included aspen, yellow poplar, hard maple, and kang duan, all of which are light-colored porous wood [31]. Herein, in order to expand the research on the structural color modification of wood surfaces and to promote its industrial application, the traditional brushing method was used to construct a structural color-modified layer on the surface of European beech wood.…”

Influence of Cell Characteristics on the Construction of Structural Color Layers on Wood Surfaces

“…Secondly, the seven timbers include six broadleaf and one coniferous timber, representing two typical types of timber. Crucially, the choice of these six broadleaf timbers builds upon previous research [20] and exhibits variations in type, number, cell diameter, and smoothness of vessels, offering a degree of representativeness. Additionally, the selection encompasses woods with diverse anatomical structures and cell diameters, fulfilling our research objective of investigating the impact of wood surface cell characteristics on the formation of structural color layers.…”