Abstract Purpose : In this study, α-Lipoic acid and pyridine were added to hydrogel materials and silicone hydrogel materials, respectively, to manufacture contact lens to evaluate changes in physical properties. Methods : N,N-Dimethylacrylamide (DMA), 2,2'-Azobis (2-methylpropionitrile) (AIBN), an initiator, and Ethylene glycol dimethacrylate (EGDMA), crosslinking agent, were used basic mixing ratio, and hydrogel materials were prepared by thermopolymerization at 100°C for 1 hour based on 2-Hydroxyethyl methacrylate (HEMA). Silicone hydrogel materials were prepared by thermopolymerization at 130°C for 2 hours based on Silicone monomer (SID). The properties of contact lenses were evaluated by adding 0.05% of 3-hydroxypyridine N-oxide and (R)-(+)-α-Lipoic acid by ratio to each material. Results : A lens manufactured by adding alpha lipoic acid to silicone hydrogel materials showed a tendency to increase wettability and decrease refractive index. A lens manufactured by adding pyridine to silicone hydrogel materials showed UV-A blocking ability, and the refractive index tended to increase. In addition, a contact lens manufactured by adding alpha lipoic acid and pyridine together showed antimicrobial properties, reduced surface roughness, and increased wettability and oxygen permeability according to the ratio of alpha lipoic acid addition. Conclusion : It is judged that alpha lipoic acid and pyridine are expected to improve wettability and oxygen permeability of the lens and to be used as contact lens materials with antibacterial properties. Key words : Alpha lipoic acid, Antimicrobial, Oxygen permeability, Pyridine, Wettability

Abstract Purpose : This study analyzed physical properties using 1,6-Hexanediol diacrylate (HDDA) as an additive to improve functionality of hydrogel lens such as durability. It was checked whether HDDA can be applied as a crosslinking agent in place of ethylene glycol dimethacrylate (EGDMA). Methods : Polymerization used thermal polymerization and photopolymerization methods, and HDDA was added to each polymerization method at a ratio of 1∼20%. Optical and physical characteristics of the manufactured lens were evaluated by measuring spectral transmittance, refractive index, water content, tensile strength, contact angle, and AFM. Results : Regardless of the polymerization method, the tensile strength ranged from 0.232~0.408 kgf/mm2 in thermal polymerization and from 0.146~0.429 kgf/mm2 depending on the addition ratio of HDDA. In addition, as a result of using HDDA instead of EGDMA, it was confirmed that the physical characteristics of the lens were similar to that of EGDMA, and in the case of tensile strength, HDDA was much improved. Conclusion : HDDA has been shown to be effective in improving the functionality of hydrogel lens and to improve stability and durability. In addition, it is believed that it can be used in various ways as an ophthalmic material as well as a photopolymerization crosslinking agent. Key words : Crosslinking agent, Tensile strength, 1,6-Hexanediol diacrylate, Hydrogel lens

목적 : 최근 전자기기의 발달로 인해 근거리 작업이 증가하고 있으며, 이로 인해 안 건강에 대한 우려가 증가함 에 따라 청광 차단에 대한 관심이 증가하고 있다. 방법 : 유해 광선 차단이 가능한 기능성 콘택트렌즈 소재 개발을 위해 reactive yellow 86을 안료 중합체에, 그리고 propyl gallate를 실리콘 하이드로겔 소재에 첨가제로 각각 사용하여 안 의료용 소프트 콘택트렌즈 제조에 적용하였다. 결과 : propyl gallate의 첨가량에 따라 접촉각이 68.25~42.50˚로 측정되었으며, 습윤성이 향상되는 것으로 나타났다. 또한, 제조된 컬러 소프트 콘택트렌즈는 산소투과성 및 습윤성이 우수함과 동시에 자외선 및 청광 차단 효과를 나타내었다. 결론 : reactive yellow 86 및 propyl gallate가 적용된 컬러 콘택트렌즈의 재료의 경우, 기본적인 안 의료용 하이드로젤 렌즈의 물성을 만족시킴과 동시에 우수한 자외선 및 청광차단 효과를 가지는 것으로 판단된다.

The physical and antibacterial properties of ophthalmic lenses fabricated by copolymerization with hydrogel monomers using two types of graphene were measured, and their usability as contact lens materials was analyzed. For polymerization, silicone monomers, including SID-OH, 3-(methacryloxy)propyl tris(trimethylsiloxy)silane, and decamethylcyclopentasiloxane, were used, and N,N-dimethylacetamide, ethylene glycol dimethacrylate as a crosslinking agent, and azobisisobutyronitrile as an initiator were added. Also, graphene oxide nanoparticle (GON) and graphene nanoplate (GNP) were used as an additive, and the physical properties of the lenses fabricated after copolymerization were evaluated. The fabricated lenses satisfied the basic physical properties of general hydrogel contact lenses and showed the characteristics of lenses with high water content, and the disadvantage of very weak durability, due to low tensile strength. However, it was confirmed that the tensile strength and antibacterial properties were greatly improved by adding GON and GNP. With GON, the oxygen permeability and refractive index of the fabricated lenses were slightly improved. Therefore, it was determined that the graphene materials used in this study can be used in various ways as a contact lens material.

In this study, lenses are fabricated using various nanomaterials as additives to a silicone polymer made with an optimum mixing ratio and short polymerization time. In addition, PVP is added at a ratio of 1% to investigate the physical properties according to the degree of dispersion, and the compatibility with hydrophobic silicone and the possibility of application as a functional lens material are confirmed. The main materials are SIU as a silicone monomer, DMA, a hydrophilic copolymer, EGDMA as a crosslinking agent, and 2H2M as a photoinitiator. Holmium (III) oxide, Europium (III) oxide, aluminum oxide, and PVP are used. When Holmium (III) oxide and Europium (III) oxide are added based on the Ref sample, the characteristics of the lens tend to be similar overall, and the aluminum oxide shows a tendency slightly different from the previous two oxides. This material can be used as a silicone lens material with various nano oxides and polyvinylpyrrolidone (PVP) acting as a dispersant.

목적 : 본 연구는 Polydimethylsiloxane(PDMS)를 기반으로 다양한 첨가제를 사용하여 고 기능성 안 의료용 고분자를 제조한 후, 제조된 렌즈 표면에 생체적합성 및 습윤성이 우수한 collagen을 코팅하여 물성을 비교 분석 하였다. 방법 : 렌즈 제조를 위해 PDMS와 친수성 모노머인 N,N-dimethylacrylamide(DMA), 2-Hydroxyethyl methacrylate(HEMA)를 주재료로 사용하였으며, 교차결합제인 Ethylene glycol dimethacrylate(EGDMA)와 열 개시제인 Azobisisobutyronitrile(AIBN)을 사용하였다. 또한 기능성 첨가제로는 1,3-Bis(3-aminopropyl) tetramethyldisiloxane(TMDS), Polyvinylpyrrolidone(PVP), 2-(Trifluoromethyl)styrene 및 collagen을 사 용하였다. 제조된 렌즈의 물성 평가를 위해 광투과율, 굴절률, 함수율, 산소투과율 그리고 인장강도를 각각 측정하였으 며, 접촉각 측정을 통해 습윤성을 평가하였다. 결과 : TMDS의 첨가비율에 따라 렌즈의 산소투과율은 약 28~45 ×10⁻¹¹(cm²/sec)(mlO²/ml×mmHg)으로 나타내었으며, PVP 및 2-(Trifluoromethyl)styrene가 첨가된 렌즈의 습윤성 및 인장강도는 56~46° 그리고 0.11~0.17 kgf/mm² 의 범위로 각각 나타났다. 다양한 첨가제를 사용함으로써 제조된 렌즈의 기능성이 향상되었 으며, 특히 콜라겐 첨가제의 사용은 하이드로겔 표면의 접촉각을 매우 감소시켜 우수한 습윤성을 가지는 것으로 나타났다. 결론 : TMDS, PVP 그리고 2-(Trifluoromethyl)styrene은 실리콘 하이드로겔 렌즈의 기능성 향상에 효과적 이며, 첨가제로서의 collagen 사용은 렌즈의 습윤성을 향상시키는 것으로 나타나 본 연구에서 사용된 재료는 안의 료용으로 다양하게 활용될 수 있을 것으로 판단된다.

This study uses silicone monomer, DMA, crosslinking agent EGDMA, and initiator AIBN as a basic combination to prepare hydrogel lenses using fluorine-based perfluoro polyether and iron oxide and zinc oxide nanoparticles as additives. After manufacturing the lens using iron oxide nanoparticles and zinc oxide nanoparticles, the optical, physical properties, and polymerization stability are evaluated to investigate the possibility of application as a functional hydrogel lens material. As a result of this experiment, it is found that the addition of the wetting material containing fluorine changes the surface energy of the produced hydrogel lens, thereby improving the wettability. Also, the addition of iron oxide and zinc oxide nanoparticles satisfies the basic hydrogel ophthalmic lens properties and slightly increases the UV blocking performance; it also increases the tensile strength by improving the durability of the hydrogel lens. The polymerization stability of the nanoparticles evaluated through the eluate test is found to be excellent. Therefore, it is judged that these materials can be used in various conditions as high functional hydrogel lens material.

목적 : 본 연구는 실리콘과 친수성 단량체를 포함하는 기능성 실리콘 콘택트렌즈를 제조하기 위해 Isobornyl Methacrylate 및 2-(Trifluoromethyl)styrene을 사용하여 물리적, 광학적 특성을 분석하였다. 방법 : 고분자의 중합은 실리콘 모노머와 친수성 단량체인 DMA(N,N-Dimethylacrylamide), 가교제인 EGDMA (Ethylene glycol dimethacrylate) 그리고 개시제인 AIBN(azobisisobutyronitrile)을 사용하여 공중합하였다. 첨 가제는 Isobornyl Methacrylate와 2-(Trifluoromethyl)styrene를 각각 사용하였으며, 제조된 콘택트렌즈의 물 성 변화를 알아보기 위해 분광투과율, 굴절률, 산소투과율, 인장강도 등을 측정하였다. 결과 : 제조된 친수성 콘택트렌즈의 산소투과율은 실리콘의 영향으로 33.22×10-11(cm2/s)(mlO2/ml×mmHg) 으로 나타났다. 첨가제인 Isobornyl Methacrylate의 양이 증가함에 따라 굴절률은 다소 향상되었고, 분광투과율은 첨 가제 양에 따라 가시광선 영역에서 약 15% 향상되어 투명한 콘택트렌즈가 제조되었다. 또한 2-(Trifluoromethyl) styrene의 첨가량에 따라 인장강도는 약 45% 향상된 것으로 나타났다. 결론 : 본 연구를 통해 제조된 실리콘 콘택트렌즈는 콘택트렌즈의 기본적인 물성을 만족시키면서 고산소투과성 을 가지며, Isobornyl Methacrylate 및 2-(Trifluoromethyl)styrene는 각각 상용성과 내구성을 향상시키는 것 으로 나타나 콘택트렌즈 재료로 다양하게 활용될 수 있을 것으로 판단된다.

This research is conducted to analyze the compatibility of used monomers and produce the high functional hydrogel ophthalmic polymer containing silane and nanoparticles. VTMS (vinyltrimethoxysilane), TAVS [Triacetoxy(vinyl)silane] and cobalt oxide nanoparticles are used as additives for the basic combination of SilM (silicone monomer), MMA (methyl methacrylate) and MA (methyl acrylate). Also, the materials are copolymerized with EGDMA (ethylene glycol dimethacrylate) as cross-linking agent, AIBN (thermal polymerization initiator) as the initiator. It is judged that the lenses of all combinations are optically excellent and thus have good compatibility. Measurement of the optical and physical characteristics of the manufactured hydrophilic ophthalmic polymer are different in each case. Especially for TAVS, the addition of cobalt oxide nanoparticles increases the oxygen permeability. These materials are considered to create synergy, so they can be used in functional hydrogel ophthalmic lenses.

The purpose of this study is to fabricate an ophthalmic lens by copolymerizing two types of carbon nanotubes and hydrophilic hydrogel lens materials, and to investigate its application as an ophthalmic lens material by analyzing its physical properties and antimicrobial effect. For polymerization, HEMA (2-hydroxyethyl methacrylate), EGDMA (ethylene glycol dimethacrylate), a crosslinking agent, and AIBN (azobisisobutyronitrile), an initiator, are used as a basic combination, and a single-walled carbon nanotube and a single-walled, carboxylic-acid-functionalized carbon nanotube are used as additives. To analyze the physical properties, the water content, refractive index, breaking strength, and antimicrobial effect of the fabricated lenses are measured. The fabricated lenses satisfies all the basic properties of the basic hydrogel ophthalmic lens. The water content increases with increasing amount of additive and decreases with addition of 0.2% ratio of nanoparticles. The refractive index is inversely proportional to the water content result. As a result of the antimicrobial test of the fabricated lens, the addition of carbon nanotubes shows an excellent antimicrobial effect. Therefore, it is considered that the fabricated lens can be applied as a functional material for basic ophthalmic hydrogel lenses.

This research is carried out to analyze the effects of Styrene and PVP on the properties of silicone hydrogel lenses. Styrene group and PVP(Polyvinylpyrrolidone) are used as additives for a basic combination containing silicone monomer, TSMA(trimethylsilyl methacrylate) and DMA(n,n-dimethylacrylamide) added to the mix at ratios of 1~10 %. Silicone hydrogel lens is produced by cast-mold method. The polymerized lens sample is hydrated in a 0.9 % saline solution for 24 hours before its optical and physical characteristics are measured. Measurement of the physical characteristics of the produced material shows that the refractive index is 1.3682~1.4321, water content 77.11~45.73 %, visible light transmittance 95.14~88.20 %, and tensile strength 0.0652~0.3113 kgf. The results show a decrease of refractive index as the ratio of additives and water content decreases. The result of the stabilization test of polymerization show an increase of extractables along with increase of the ratio of additives, but the difference is not significant for all samples, so it can be judged that the stabilization of the polymer is maintained. Therefore, the additions of styrene and PVP should be taken into consideration for their effects on the physical properties of silicone hydrogel lens.

This study is carried out to evaluate the commercial feasibility of the room temperature and thermal polymerization method as a lens manufacturing method. All samples are found to be transparent after polymerization, thereby indicating that their physical and surface properties are suitable for hydrogel ophthalmic lenses. The optical and physical properties of the lenses are compared. The water content of the samples that are prepared via a room temperature polymerization process decreases with the addition of MMA as compared to the water content of the samples that are prepared via thermal polymerization. When MMA and DMA are used as an additive for improving functionality, the wettability of the lenses increases. By measuring the AFM, the surface roughness is shown to improve more than MMA and DMA. Therefore, it is judged to be an appropriate process for manufacturing hydrogel lenses with high functionality.

In this study, a multifunctional ophthalmic lens material with an electromagnetic shielding effect, high oxygen permeability, and high water content is tested, and its applicability is evaluated. Metal oxide nanoparticles are applied to the ophthalmic lens material for vision correction to shield harmful electromagnetic waves; the pyridine group is used to improve the antibacterial effect; and silicone substituted with urethane and acrylate is employed to increase the oxygen permeability and water content. In addition, multifunctional tinted ophthalmic lens materials are studied using lens materials with an excellent antibacterial effect (2,6-difluoropyridine, 2-fluoro-4-pyridinecarboxylic acid) and functional (UV protection, high wettability) lens materials (2,4-dihydroxy benzophenone, 2-hydroxy-4-(methacryloyloxy)benzophenone). To solve problems such as air bubbles generated during the polymerization process for the manufacturing and turbidity of the lens surface, polymerization conditions in which the defect rate is minimized are determined. The results show that the polymerization temperature and time are most appropriate when they are 110 oC and 40 minutes, respectively. The optimum injection amount of the polymerization solution is 350 ms. The turbid phenomenon that appears in lens processing is improved by 10 to 95% according to the test time and conditions.