Effect of UV Curing on Electrical Properties of a UV‐Curable co‐Polyacrylate/Silica Nanocomposite as a Transparent Encapsulation Resin for Device Packaging

Abstract

Electrical properties of UV‐curable co‐polyacrylate/silica nanocomposite resins prepared via sol‐gel process for device encapsulation were investigated. It was found that, by appropriate UV curing process and the formation of nanoscale silica particles finely dispersed in the resin matrix, the leakage current density of the nanocomposite resin films decreases from 235 to 1.3 nA · cm−2 at the applied electrical field of 10 kV · cm−1. The silica nanoparticles also restricted the motions of polar functional groups in organic matrix that the nanocomposite films with satisfactory dielectric properties [dielectric constant (ε) = 3.93 and tangent loss (tanδ = 0.0472) could be obtained. Chemical structure analyses revealed that excessive UV curing results in photooxidation and/or photodegradation in resin samples, leading to the polar groups and ionic/radical segments in organic matrix as well as the SiOSi structure in the vicinity of silica nanoparticles. These organic/inorganic functional groups generated more permeation paths for charge carrier migration and hence deteriorated the electrical properties of the nanocomposite samples. Though post‐baking treatment at 80 °C for 1 h followed by UV curing improved the rigidity of the resin sample, it brought the polar functional groups closer to each other and similarly degraded electrical properties of the nanocomposite resins.magnified image

Preparation and characterizations of tantalum pentoxide (Ta2O5) nanoparticles and UV‐curable Ta2O5‐acrylic nanocomposites

“…It is speculated that the too many Ta 2 O 5 particles may hinder the propagation of UV light into the interior of nanocomposites and thus cause the incomplete sample curing. A prolonged curing time was thus required for high‐filler‐loading samples; nevertheless, excessive UV exposure might induce the photo‐degradation of polymer matrix and lead to the degradation of thermal stability of nanocomposite samples 30–32…”

Study on Nanosilica Reinforced Stereolithography Resin

“…Seldom have reports involved the modification of SL resins with nanomaterials. On the other hand, many papers [22][23][24][25][26][27][28] have reported that nanomaterials show considerable improvement or novel performance compared with traditional materials. Therefore, Sandoval et al [29] and Sandoval and Wicker [30] successfully prepared SL nanocomposites using Somos 11120, 10110, and multi-walled carbon nanotubes, and investigated the mechanical properties of the modified SL resins.…”

Syntheses of novel photosensitive polysiloxanes and their effects on properties of UV-cured epoxy methacrylate coatings

“…Many silicon components have been applied to non-UV curing systems, while there are only several types incorporated into the UV-curable, such as organosilicone-containing hybrid systems [13][14][15] and inorganicorganic silicon hybrid. 3,5,16,17 Those used silicon components still do not seem to present large numbers of photosensitive groups or more efficiently enhance the properties of UV-cured coatings. Polysiloxanes are capable not only of providing two sites for crosslinks, but also of forming functional chains through bond formation with silicon.…”