## 3 Materials and Experimental Setup  
The soap-free method was utilized to prepare the PSM, resulting in microspheres with excellent homogeneity and stable properties. The synthesis process is outlined as follows: first, a sealed glass reactor connected to an agitator was prepared. A total of 500 mL of deionized water was added to the reactor, and the system was treated with nitrogen for 2 h. The agitator speed was set to 500 rpm, and the constant temperature tank was set to 90 \({}^{\circ}\)C. Next, the styrene was cleaned using a 5% NaOH solution. This cleaning process was repeated 2-3 times to remove the inhibitor from the styrene. Subsequently, the styrene was washed with deionized water 3-4 times, and the pH value of the cleaning solution was monitored until it reached 7. Afterward, 35 mL of the washed styrene was measured and quickly added to the reactor. Following a 15 min interval, 30 mL of KPS (Potassium Persulfate) initiator was measured and swiftly added to the reactor. The reaction was allowed to proceed for 4 h. The agitator and the constant temperature tank were turned off, and the reactor was cooled to room temperature. The PSM obtained through these steps can be further utilized in the research and fabrication of PS photonic crystals. To obtain the PSM-SA, the treated PSM suspension was transferred to a gold mirror using the liquid-level transfer method. The preparation process is illustrated in Figure 1. Initially, the PSM suspension and anhydrous ethanol were first transferred in a 1:1 ratio, using a pipette gun, to a centrifuge tube, with 50 \(\upmu\)L of each being transferred. The resulting solution is enough to cover the slide completely, allowing just enough for a complete study. To ensure thorough mixing of the PS solution and ethanol, the mixture was subjected to 10 min of ultrasonication. Subsequently, deionized water was placed on a glass slide. Utilizing the surface tension and capillary forces between the fine particles, the uniformly mixed PS solution was gently floated on the surface of the liquid droplet. It was allowed to stand for 30 min. Next, to save experiment time, filter paper was used to absorb excess water from the slide and the slide placed into a beaker filled with water, allowing the self-assembled PSM film to float on the water surface. The PSM film on the water surface was carefully extracted using tweezers while holding a gold mirror. The film was then allowed to stand for 20 min to ensure a secure and completely dry adhesion. This process resulted in the production of the PSM-SA. The morphological analysis and characterization of the PSM are crucial steps in our investigation. Field-emission scanning electron microscopy (SEM) is employed to explore the morphology and size distribution of the PSM, as depicted in Figure 2a. The SEM images provide valuable insights into the structural characteristics of these microspheres. It can be seen that the microspheres are uniform in shape and size and uniform in arrangement. In addition to morphological analysis, we conducted Raman spectroscopy to assess the material quality and composition of the PSM-SA samples, as presented in Figure 2b. Raman spectroscopy is a powerful tool for identifying and quantifying molecular vibrations in materials. In our spectra, specific peaks corresponding to the PS material [40] are clearly observed, providing a deeper understanding of the chemical characteristics of our samples. For example, the Raman spectra reveal distinctive peaks indicative of PS. The peak at 1002 cm\({}^{-1}\) corresponds to aromatic respiration, while the peak at 620 cm\({}^{-1}\) indicates the deformation of the benzene ring. Further insights are gained from peaks at 902 cm\({}^{-1}\) and 1023 cm\({}^{-1}\), which are associated with the out-of-plane bending vibrations of C-H and C-O bonds, respectively. The C-H bending vibration occurs at 1030 cm\({}^{-1}\). Additionally, peaks at 1490 cm\({}^{-1}\), 1447 cm\({}^{-1}\), and 1602 cm\({}^{-1}\) correspond to the stretching vibrations of the C=C bond on the benzene ring.