Structural Study of Silica Coating Thin Layers Prepared from Perhydropolysilazane: Substrate Dependence and Water Penetration Structure

Coatings

Yoshio Hasegawa¹  Tomotake Niizeki¹  Sachiko Nagayama¹  Masae Sahara²  Noboru Miyata²  Kazuhiro Akutsu² 

[1] ART KAGAKU Co., Ltd., 3135-20 Muramatsu, Tokai, Ibaraki 319-1112, Japan;Comprehensive Research Organization for Science and Society (CROSS), 162-1 Shirakata, Tokai, Ibaraki 319-1106, Japan;

关键词: perhydropolysilazane;    neutron reflectivity;    water penetration;   

DOI  :  10.3390/coatings6040064

来源: DOAJ

【 摘 要 】

The structure of perhydropolysilazane (PHPS)-derived silica (PDS) waterproof thin layers synthesized by curing at 60 °C for 1 h and allowed to stand for 48 h at 20 °C on various kinds of substrates was studied. Neutron reflectivity (NR) analysis suggested that uniform PDS thin layers were synthesized on the substrates, and the density of the layers varied depending on the type of substrate. Additionally, since the change in PDS density is correlated with the pKa value of the OH group on the substrate, it can be suggested that the acidity of the substrate would be one of the main factors determining the density of the coated PDS thin layers. For the water penetration structure study, NR analysis revealed that the depth of water penetration into the PDS layers was below 500 Å, and the hydration number of the SiO2 molecule was estimated to be 8.0–9.0. From these results, we concluded that water penetration occurred by the formation of water-pool structures in the PDS layers, and the randomly formed nano-air holes lead to a reduction in the probability of water penetration into the deep regions of the PDS layers.

【 授权许可】

Unknown