Preparation of monodisperse polystyrene microspheres and optical performance of its diffusive‐agent application

Abstract

Abstract— Two monodisperse polystyrene microspheres, 2.76 and 9.25 μm in diameter, were prepared by dispersion polymerization in an ethanol/iso‐propanol/water media. 2,2′‐azobis(isobutyronitrile) (AIBN) and poly(acrylic acid) (PAA) were utilized as the initiator and steric stabilizer, respectively. Optical properties including total transmittance (T%) and transmittance haze (H%) were determined when these two monodisperse polystyrene microspheres were applied as diffusive agents. This paper mainly discusses (1) different particle‐size effects and its hybrid behavior, (2) different thicknesses for the diffusion‐layer effect, and (3) the effects of diffusion‐layer arrangement and direction of incident light on the total transmittance (T%) and transmittance haze (H%).

Light‐diffusing materials for LED illumination applications: Comparing the effectiveness of two typical light‐diffusing agents

“…As shown in Figure , plates with different thicknesses reach maximum haze at a surface area of 100 cm 2 for the silicone microsphere‐filled LDM plate and at 200 cm 2 for the acrylic microsphere‐filled LDM plate. The phenomenon of LDMs achieving maximal haze at a specific threshold of total light‐diffusing particle surface area has also been reported . According to the literature, the diffusing properties are determined by the surface area of the light‐diffusing agents and are less related to the particle size or size distribution, although the particle size and size distribution of light‐diffusing particles are important factors that influence the diffusing properties of LDMs.…”

“…The phenomenon of LDMs achieving maximal haze at a specific threshold of total light-diffusing particle surface area has also been reported. [11][12][13] According to the literature, 12,13 the diffusing properties are determined by the surface area of the lightdiffusing agents and are less related to the particle size or size distribution, although the particle size and size distribution of light-diffusing particles are important factors that influence the diffusing properties of LDMs. Additionally, when a specific type of light-diffusing agent is used, LDMs with the same lightdiffusing particle surface area will exhibit the same haze and transmittance, although the particles may have different particle sizes or particle size distributions.…”

“…Additionally, when a specific type of light-diffusing agent is used, LDMs with the same lightdiffusing particle surface area will exhibit the same haze and transmittance, although the particles may have different particle sizes or particle size distributions. [11][12][13] The difference in the refractive indices of the light-diffusing agent and matrix in LDMs is another important factor that determines the diffusing properties of these materials. As the refractive index difference increases, the amount of scattered light increases; as a result, a smaller diffusing surface area is required to achieve maximal haze.…”

“…[1][2][3][4]9,10 In the composites prepared by this method, the diameter and relative refractive index of the diffusing agent are critical for the light-diffusing properties. 1,2,[11][12][13] If a light-diffusing agent with suitable diameter and relative refractive index is selected, the forward scattering of the LDM will be increased, resulting in both high haze and high transmittance.…”

“…Therefore, the widely used alternative method is to disperse microspheres, i.e., so‐called light‐diffusing agents, into a transparent polymer resin via a mixing process . In the composites prepared by this method, the diameter and relative refractive index of the diffusing agent are critical for the light‐diffusing properties . If a light‐diffusing agent with suitable diameter and relative refractive index is selected, the forward scattering of the LDM will be increased, resulting in both high haze and high transmittance.…”