Aligned HNT for mechanical reinforcement, abrasion resistance, and tranparency in solar cell coatings

Halloysite nanotubes (HNT), a kind of naturally formed ceramics, encompass high aspect ratio, stiffness and low cost while remain understudied about their coating usage. Theoretical and experimental results have shown a modulus as high as 400 GPa. In this study, HNT was included in polymer based thin films fabricated using coating method on glass substrate. Mechanical tests have shown a consistent increase in stiffness, hardness and scratch resistance as compared to polymer materials without HNT. Composite mechanics based calculations showed as high as 300 GPa in HNT modulus, which is close to theoretical predictions and top in literature. The high reinforcement as well as wear resistance was attributed to high tube orientations, as revealed from electron microscopy. By matching the refractive indices between segments in composites, the coating materials can display transparency up to 90% even at a high concentration of 20 wt% loadings of HNTs. This study aims at development of environmentally friendly and cost effective coating, which is highly potential to be commercialized in solar cell industries.