Fabrication of micro-pyramid arrays on PETG films by roll-to-roll hot embossing

•Micro-pyramid arrays were fabricated on PETG films by roll-to-roll hot embossing.•High roller temperature favors forming of micro-pyramid arrays but will cause film damage.•Increase of roller speed will lead to higher defect density.•Micro-pyramid arrays on PETG films have good performance of light reflection.

Roll-to-roll hot embossing is a promising method for micro-structures fabrication with high throughput. Micro-pyramid arrays with the average height of 65 μm and the bottom edge length of 175 μm were successfully fabricated on optical transparent poly(ethylene terephthalate-co-1,4-cylclohexylenedimethylene terephthalate) (PETG) films via roll-to-roll hot embossing. No whitening caused by crystallization happened on PETG films during embossing. The effects of roller temperature, roller speed and applied force on the replication quality of micro-pyramid arrays were investigated. According to the effects we studied, the embossing conditions can be optimized for fabrication of high micro-pyramid arrays with low defects percentage. Optical microscope images show that micro-pyramid arrays with the average height over 60 μm have good reflection performance. The PETG films with micro-pyramid arrays can be of applications in reflective films field.

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