Resilient moth-eye nanoimprinted antireflective and self-cleaning TiO2 sputter-coated PMMA films

• Moth-eye nanostructures are amongst the most remarkable surfaces in nature because of their multi-functionality including antireflection, self-cleaning and bactericidal ability. Moth-eye surfaces consist of subwavelength arrays of tapered nanostructures, which are challenging to reproduce artificially. Nanoimprint lithography is probably one of the most suited technologies for this purpose. However, the poor mechanical resilience and durability of the polymeric nanocones when exposed to the environment, hinders their use in actual applications. To overcome these limitations, this work demonstrates the use of a thin oxide coating over the polymer moth-eye features imprinted on poly methyl methacrylate (PMMA) films. Particularly TiO2 conformal thin film coatings are deposited by unipolar pulsed dc magnetron sputtering over the antireflective nanopatterns acting as encapsulant. The coating, while preserving the antireflective properties, protects the nanostructures against mechanical scratching and improves substantially their thermal stability to over 250 ?. Furthermore, the TiO2 layer provides additional photoinduced self-cleaning functionality and at the same time it protects the matrix from UV photodegradation. The robust and durable antireflective surfaces developed here may find application on solar cells covers, flat panel displays or on optical components.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Bearbetnings-, yt- och fogningsteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Manufacturing, Surface and Joining Technology (hsv//eng)

Keyword

Antireflective surfaces

Moth-eye surfaces

Nanoimprint lithography

Magnetron sputtering

Publication and Content Type

ref (subject category)

art (subject category)