• • Achieved a blue shift of ~213 nm in an NPC with φ=0.23 fabricated from 170 nm PS@V-SiO2 nanospheres under strain up to 64%, enabling a color gradient from red to blue; this wide tunability is critical for strain sensing and anti-counterfeiting applications requiring high spectral resolution.
• • Demonstrated that UV curing promotes copolymerization between surface C=C bonds of nanospheres and the PEGPEA matrix, reducing interfacial scattering and yielding highly transparent films; transparency is essential for display and optical device integration.
• • Identified that non-uniform polymer shrinkage causes ordering variations, particularly at low volume fractions (φ ≤ 0.23), which initially enhances reflection intensity upon stretching but later introduces defects and reduces reflectivity; understanding this trade-off is vital for optimizing mechanochromic performance.
• • Comparative analysis across SiO2–PEGDA, SiO2–PEGPEA, and PS@V-SiO2–PEGDA systems revealed that interfacial scattering is governed by synergistic effects of interfacial covalent polymerization, refractive index matching, and crosslinking density; this provides a design rule for minimizing optical losses in composite photonic materials.