Characterization of Nanomaterial-Based Contact Lenses by Atomic Force Microscopy

Abstract

In this paper the comparative studies were conducted of the surface areas of nanophotonic contact lens and contact lens made from base material, measured by Nanoprobe Atomic Force Microscope. Nanoprobe atomic force microscopy (AFM) provides information on the size structure on nano scale level, the form of recorded structures (cavities), their distribution of the surface, and the total roughness of the scanned area. The atomic force microscope used in this study is a SPM-5200 of JEOL, Japan. AFM consists of a cantilever with a sharp tip (probe) at its end that is used to scan the specimen surface. Images of the specimen surface are created by measuring the deflection of the cantilever. The cantilever used in this study is produced by MikroMasch (Estonia) by trade name NCS18/Co-Cr. This AFM probe is silicon etched probe tip that has conical shape. It is coated with Co and Cr layers. Images of surface topography were obtained for each type of contact lenses. The base material of contact lens was made from PMMA and the nanophotonic contact lens was made of fullerene doped PMMA. Fullerenes were used because of their good transitive characteristics in ultraviolet, visible and near infrared light spectrums. Measurements were done at room temperature. Results of topography for both materials are presented and compared.

Effects of Image Size and Sample Areas on Comparison of Contact Lens Surfaces Based on Fractal Dimension

“…Therefore, fractal dimension, as numerical representation of surface roughness, could be used for contact lenses comparison. We already used the result of comparison as feedback for machining process optimization [1], for contact lens wear-out diagnostics [5] and for ongoing investigation that considers new "nanophotonic" material for gas permeable contact lenses [6].…”

Comparative Study of Classical and Nanophotonic Materials for RGP Contact Lenses by Scanning Probe Microscopy

“…The AFM has proven to be a great asset for characterization of surface properties of various materials. It has been widely used even to measure different aspects of contact lenses, such as surface roughness [8][9][10], lateral forces [11,12] and also their magnetic properties [13,14].…”

Nanophotonic Rigid Contact Lenses: Engineering and Characterization

“…All relevant materials have been compared to assess suitability for contact lenses manufacture. Materials were characterized by their surface and electromagnetic properties using Atomic Force Microscopy (AFM) and Magnetic Force Microscopy (MFM), which have been proven to be reliable characterization methods for contact lens investigations [6,7,8,9,10,11].…”