Improved Catalytic Durability of Pt-Particle/ABS for H₂O₂ Decomposition in Contact Lens Cleaning.

Yuji Ohkubo,Osamu Mori,Satoshi Seino,Katsuyoshi Endo,Tomonori Aoki,Kazuya Yamamura,Issaku Ito

doi:10.3390/nano9030342

Yuji Ohkubo, Osamu Mori + Show 5 more

Open Access

https://doi.org/10.3390/nano9030342

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Abstract

In a previous study, Pt nanoparticles were supported on a substrate of acrylonitrile–butadiene–styrene copolymer (ABS) to give the ABS surface catalytic activity for H2O2 decomposition during contact lens cleaning. Although the Pt-particle/ABS catalysts exhibited considerably high specific catalytic activity for H2O2 decomposition, the catalytic activity decreased with increasing numbers of repeated usage, which meant the durability of the catalytic activity was low. Therefore, to improve the catalytic durability in this study, we proposed two types of pretreatments, as well as a combination of these treatments before supporting Pt nanoparticles on the ABS substrate. In the first method, the ABS substrate was etched, and in the second method, the surface charge of the ABS substrate was controlled. A combination of etching and surface charge control was also applied as a third method. The effects of these pretreatments on the surface morphology, surface chemical composition, deposition behavior of Pt particles, and Pt loading weight were investigated by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), cross-sectional SEM, and inductively coupled plasma atomic emission spectroscopy (ICP-AES), respectively. Both etching and controlling the surface charge effectively improved the catalytic durability for H2O2 decomposition. In addition, the combination treatment was the most effective.

Highlights

The number of contact lens wearers is estimated to be approximately 140 million all over the world [1]
When the acrylonitrile– butadiene–styrene copolymer (ABS) substrate was etched, the intensity of the peak indexed to C–H and C–C (285 eV) decreased whereas the intensity of the peaks indexed to C=O–O (289 eV), C=O (287.5 eV), C–N and C–O (286.5 eV) increased
When the surface charge of the ABS substrate was controlled, the intensity of the peak indexed to C–H and C–C (285 eV) decreased, whereas that of the peaks indexed to C–N and C–O (286.5 eV) increased, indicating that the ABS surface was covered with surface charge controllers

Summary

Introduction

The number of contact lens wearers is estimated to be approximately 140 million all over the world [1]. Contact lenses are divided into two types: disposable and extended wear. Extended-wear contact lenses can be used repeatedly, which offers long-term cost advantages. To prevent eye troubles, a repeatable-use-type contact lens requires daily cleaning and sterilization. Three methods are used to clean and sterilize contact lenses: boiling, and cleaning in either H2O2 or multipurpose solution (MPS). When cleaning with a MPS, a single solution plays the roles of cleaning, sterilizing, and preserving lenses. MPS cleaning is a simple method, and about 70% of contact lens wearers currently use an MPS to clean their lenses [3]. If contact lens wearers are not careful while using the MPS, eye troubles are likely to occur due to inadequate sterilization. In H2O2 cleaning, a 35,000 ppm H2O2 solution is used to clean and sterilize contact lenses

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