The functionality of soft contact lenses depends strongly on the water content and their water-transport ability. This study was conducted in order to examine the state of water in two sets of soft contact lenses: VSO38, pHEMA Filcon I 1, and VSO50, copolymer of HEMA and VP Filcon II 1 (HEMA = 2-hydroxy-ethyl methacrylate; VP = vinyl pyrrolidone). Hydrogel lenses were studied using near-infrared spectroscopy and the novel Aquaphotomics approach in order to determine the state of water in materials based on their near-infrared spectra. Aquaphotomics approach investigates absorption at specific vibrational bands of water’s covalent and hydrogen bonds which can provide information on how the water structure changes with the structural change of the polymer network. Principal component analysis and specific star-chart “aquagram” were used to analyse water spectral pattern in hydrogel materials. The findings show that material VSO38 has water predominantly organized in bound state, while material with higher water content, VSO50, has more free and weakly hydrogen bonded water. Our findings define in detail exact water species existing and interacting with the polymer network. The results show qualitative and quantitative possibilities of Aquaphotomics for better modelling and understanding water behaviour in hydrogel materials.
The aim was to develop new materials that would, after appropriate machining processes, improve the surface roughness and wettability of contact lenses. The samples used in this investigation were standard rigid gas-permeable (RGP) SOLEKO contact lenses, made of poly-MMA-co-siloxy silane methacrylate material (known under the commercial name SP40 TM ), and its modifications by adding three nanomaterials: fullerene C60 (designated as SP40-A), fullerol C60(OH)24 (designated as SP40-B) and methformin hydroxylate fullerene C60(OH)12(OC4N5H10)12 (designated as SP40-C). Both atomic force microscopy (AFM) and magnetic force microscopy (MFM) were used to measure the topography and gradient of the magnetic field of the nanophotonic materials and the reference samples. According to the magnetic properties of all the materials yielded by MFM it can be concluded that adding fullerene and its derivatives certainly reduces the spectrum of the phase shifts angle by almost 50 %, which increases the paramagnetic characteristics of the nanophotonic material. The positive result of nanophotonic materials characterization is the fact that the roughness parameter values for all of these materials, are lower than those for the basic material. A surface lacunarity analysis, based on in-house procedures for determining the lacunarity value of contact lens surfaces, confirms the influence of surface topology on the tear film volume distribution and, consequently, the contact lens' surface lubrication. The presence of carbon nanomaterials, according to the surface roughness parameters, are improved for rigid gas-permeable (RGP) contact lenses made from nanophotonic polymer materials compared to those produced from the basic material. Keywords: fullerenes, polymer materials, surface roughness, atomic force microscopy, magnetic force microscopy Namen je bil razviti nov material, ki bi po ustrezni strojni obdelavi zmanj{al hrapavost povr{ine in omo~ljivost kontaktnih le~. Vzorci, uporabljeni v tej raziskavi so bile standardne toge, za plin prepustne (RGP) SOLEKO kontaktne le~e, narejene iz poli-MMA-ko-siloksi silan metakrilatnega materiala (s komercialnim imenom poznanega SP40 TM ) in njihove modifikacije z dodatkom treh nanomaterialov: fulerena C60 (ozna~enega kot SP40-A), fulerola C60(OH)24 (ozna~enega z SP40-B) in metformin hidroksilat fulerena C60(OH)12(OC4N5H10)12 (ozna~enega z SP40-C). Uporabljeni so bili: mikroskopija na atomsko silo (AFM), mikroskopija na magnetno silo (MFM) za merjenje topografije in gradient magnetnega polja nanofotonskih materialov in referen~nih vzorcev. Skladno z magnetnimi lastnostmi vseh materialov, dobljenih z MFM, je mogo~e zaklju~iti, da dodajanje fulerenov in njegovih izpeljank, mo~no zmanj{a spekter kotov faznega premika za skoraj 50 %, kar pove~a paramagnetne zna~ilnosti nanofotonskih materialov. Pozitivni rezultati karakterizacije nanofotonskih materialov so, da so vrednosti parametra hrapavosti pri vseh teh materialih ni`je kot pri osnovnem materialu. Analiza povr{inske razporeditve praznin, na osnovi...
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.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.