Photopolymerization resins are extensively used across several industrial fields, such as optical waveguides, three-dimensional（3D）printing, inks, coatings, adhesives, and dental materials. Recently, photopolymerization has primarily been performed using ultraviolet（UV）or visible light sources. UV and visible light cannot penetrate deeply into biological and polymeric material while near-infrared（NIR）light is found to be capable of deeper penetration into such material compared to with UV light. Single-photon and two-photon absorption chromophore sensitized photopolymerization has been developed in the NIR region. An important application of photopolymerization is its use in micro- and nanooptics. This article introduces the NIR photopolymerization resins, and its application to optical devices.

ポリプロピレン（以下，PP）基材上に可逆的付加－開裂連鎖移動（Reversible Addition-Fragmentation ChainTransfer: RAFT）型のリビングラジカル重合法にて生体適合性のある2 種類の親水性モノマーを用いてブロックコポリマーブラシとして二層構造のコーティングを施した。2 種のモノマーの特定の分子量比において，摩擦係数0.01未満となる超低摩擦化の実現とともに，摩擦係数が速度に依存しないコーティングが実現できた。また，超低摩擦化に対して，既知である成立要素の分子量均一性，十分な膜厚及び分子屹立の他にも，表面粗さ，ヤング率，損失弾性率，含水量の成立要素が関与していることが示唆された。特に超低摩擦化に対しては「表面粗さ」が摩擦係数と強い相関性があり，すべり速度依存性に対しては，一般的な医療機器の使用における速度範囲（20～240 mm/min）において，「ヤング率」及び「損失弾性率」に強い相関があることから，表面粗さが小さく，弾性を一定以上有して，かつ損失弾性率が低く，本研究のような二層構造のコーティングを施すことが望ましい。

The Japanese industry has turned the extended timelines required for materials development into an advantage, establishing close coordination within its value chain and showcasing its exceptional niche-leading products to the world. However, in light of current challenges, it has become increasingly difficult to remain competitive as a niche player alone. This is because reducing environmental impact through weight reduction necessitates the development of complex and comprehensive materials-so-called multi-materials. Adhesive technology, without question, plays a crucial role in this context. In recent years, a methodology known as the “digital twin” has been proposed. The digital twin enhances problem-solving capabilities by creating a twin structure of the physical and cyber worlds in an advanced digital space（DX）, allowing for mutual feedback between physical measurements and cyber analyses. This paper presents a case study in which a challenging adhesive problem was analyzed using digital twin techniques, employing the functions of general-purpose FE software.