エポキシ接着剤でラップジョイント試験片を作製し屋外ばく露試験を実施した。被着体はアルミニウムおよびGI 鋼板を用い，表面処理は酸洗およびサンドブラストを施した。さらに組み立て後に電着塗装した試験片も準備し，自動車のドアパネル内部を模擬している。4 タイプの試験片を宮古島で28 カ月間の屋外ばく露試験を実施し，長期の耐久性を評価した。その結果，もっとも強度低下が少なかった仕様はアルミニウム合金の被着体にサンドブラスト処理を施した試験片であった。また電着塗装は，水が接着界面へ侵入しにくくする効果が認められた。すべてのタイプの試験片において，被着体の腐食が強度に与える影響が大きく，強度を大きく低下させる場合があった。実験室での温水浸漬による強度低下と比較することにより，劣化加速試験による長期強度予測の手法を提案することができた。

Cross-linked polymers such as rubber and gel contain various structural defects in their three-dimensional polymer network because of the uncontrolled cross-linking processes. The defects can be reduced or controlled in model networks, which are synthesized by end-linking of well-defined precursor polymers. This review summarizes the development in the synthesis and characterization of model networks. First, the basic concept of model networks and the possible structural defects are discussed. In the next section, attention is directed to the progress in the synthetic method of model networks, with a particular focus on the endlinking chemistry and the polymer types. Then, some important findings regarding the structure-property relationship of model networks are introduced, including the effects of the network topology as well as some unique phenomena such as supercoiling and strain-induced crystallization.

Adhesion in wet biological environments is fundamentally challenging because tissue surfaces are covered with hydration layers that inhibit direct interfacial interactions. Therefore, adhesive materials for surgical applications must achieve strong adhesion under wet environment while maintaining biocompatibility and mechanical compliance. This article reviews recent advances in wet-tolerant adhesives from the perspectives of adhesion mechanisms and integrated material design. Existing strategies are broadly classified into chemical bonding systems and physical interaction-based systems. Chemical bonding systems provide rapid and strong adhesion but may induce cytotoxicity and inflammatory responses, whereas physically interactive systems exhibit high biocompatibility and flexibility but often suffer from limited adhesion strength and durability. Recent developments have focused on integrating multiple mechanisms, including dynamic intermolecular interactions, hydration structure control, and hierarchical structural design, to overcome these tradeoffs. Particular emphasis is placed on our studies using hydrophobically modified Alaska pollock gelatin as a biomaterial platform. By controlling material morphology, including gels, particles, and sheets, distinct adhesion behaviors and functions can be achieved even within the same material system. These findings demonstrate that material morphology is an essential design factor governing wet adhesion and provide new insights into the development of next-generation biomedical adhesives.