キレイキレイ 薬用泡で出る消毒液
I found this on a website. Here we see they use katakana to write the word きれい. I am wondering what the function is. Of course, this is an advertisement and the word キレイis a brand name. But why katakana? It also can be written in hiragana since きれい is always written in hiragana. And then, I came to realize that when using katakana, this word is highly emphasized. Therefore, katakana can not only imitate sound and be used for loanwords, but also can emphasize something important. It can readily catch people's eyes.
(Source:http://kireikirei.lion.co.jp/)