Direct Laser Interference Patterning of Diffraction Gratings in Safrofilcon-A Hydrogel: Fabrication and Hydration Assessment

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

Abstract

Refractive index modification by laser micro-structuration of diffractive optical devices in ophthalmic polymers has recently been applied for refractive correction in the fields of optics and ophthalmology. In this work, Safrofilcon-A hydrogel, used as soft contact lenses, was processed by direct laser interference patterning (DLIP) to fabricate linear periodic patterns on the surface of the samples. Periodic modulation of the surface was attained under two-beam interference by using a Q-switched laser source with emission at 263 nm and 4 ns pulse duration. Features of processed areas were studied as a function of both the interference spatial period and the laser fluence. Optical confocal microscopy used to evaluate the topography of the processed samples showed that both structured height and surface roughness increased with laser fluence. Static water contact angle (WCA) measurements were carried out with deionized water droplets on the structured areas to evaluate the hydration properties of DLIP structures. It was observed that the laser structured areas induced a delay in the hydration process. Finally, microstructural changes induced in the structured areas were assessed by confocal micro-Raman spectroscopy showing that at low laser fluences the polymer structure remained almost unaltered. In addition, Raman spectra of hydrated samples recovered the original shape of areas structured at low laser fluence.

Details

Original languageEnglish
Article number679
Pages (from-to)1-9
Number of pages9
JournalPolymers
Volume13
Issue number5
Publication statusPublished - Mar 2021
Peer-reviewedYes

External IDs

PubMed 33668214
Scopus 85102168953
Mendeley afe0d93a-065e-35f7-9a1c-0f4a55f26126
ORCID /0000-0003-4333-4636/work/196675443

Keywords

Keywords

  • DLIP, Diffraction gratings, Laser materials processing, Ophthalmic materials, Polymers