Self-organized antireflective nanostructures on PMMA by ion etching

Abstract

Stochastic, self-organized nanostructures are produced by a low-pressure plasma treatment on the polymer polymethylmetacrylate (PMMA). The phenomena obtained by plasma treatment (structure formation and antireflective effect) are investigated regarding surface modifications, structure growth, and chemical modifications. Optically, the structure acts like a gradient layer with decreasing effective refractive index towards air, which is suitable for antireflection of PMMA

Ceria-Incorporated Biopolymer for Preventing Fungal Adhesion

“…These results, that the Ce 4+ was dominant in Ce oxide nanoparticles synthesized through the hydrothermal method in alkaline conditions, were already reported (Figure D). − The above results revealed that CNPs were successfully fabricated with typical characteristics of ceria with catalytic effects due to their nanosize. Many researchers have combined CNPs with other biomaterials to overcome the inherent lack of certain properties, such as lower bioactivity and poorer mechanical properties. ,− PMMA, a widely utilized biomaterial, has been previously modified by CNPs to confer extra physicomechanical properties, but the antimicrobial effects have not yet been investigated in detail. Here, CNPs were incorporated into PMMA to overcome the inherent drawback of PMMA, its poor antimicrobial properties.…”

“…A meaningful augmentation of flexural strength in a 0.5% incorporated specimen was considered due to the optimal mix of CNPs and PMMA to resist outer force. In other literature, the flexural strength was also enhanced when inorganic nanoparticles such as mesoporous silica nanoparticles were doped in PMMA. − Theoretically, the incorporation of nanoparticles into the polymer with physical binding is known to reinforce mechanical properties by generating bridging and crack deflection in the matrices. , Here, CNPs were considered to play a role as a crack deflector in the 0.5% specimen, while other conditions were suboptimal in terms of their lower amounts of reinforcement in the matrix or improper networking in the matrix . On the other hand, surface hardness, measured as the Vickers hardness, showed decreased values after the incorporation of CNPs into PMMA (Figure E, n = 10, P < 0.05).…”

Nanofibrillar Patterns by Plasma Etching: The Influence of Polymer Crystallinity and Orientation in Surface Morphology

“…For PET, the following mechanisms have been postulated: (i) differential etching of crystalline and amorphous domains, (ii) dewetting of a polar fluid film of oxidized low molecular weight fragments in small drops that act as etch masks, and (iii) redeposition of degraded material in atmospheric plasmas . For other polymers further mechanisms have also been discussed: (iv) differential etching of crystalline and amorphous domains in cellulose fibres and PP, (v) sputtered Al particles from the plasma reactor wall that redeposit onto the surface of the polymer and act as masks during plasma etching of PMMA and PEEK, (vi) anisotropic ion bombardment of the polymer surface owing to local variation in curvature (experiments were performed on spin-coated PMMA, PS, PVDF, PEDOT, PPY and photoresist materials), (vii) spontaneous perturbation and topography formation of a thin film of polymer melt as a consequence of surface instabilities induced by the electric field, , or of buckling instabilities (viii) no reference to any mechanism. ,, …”

Broadband Antireflective Structures on PMMA by Plasma Treatment

“…whereas the removal of material by ions is smaller at the peaks than in the valleys. The average etch rate for this plasma composition is between 1 and 2 nm · s −1 7…”

“…The oxidative decomposition of polymethylmetacrylate (PMMA) by microwave‐induced plasmas was reported by Gröning et al6 and confirmed for the dc‐plasma treatment process by Kaless et al7 It was demonstrated by X‐ray photoelectron spectroscopy (XPS) and Fourier‐transform infrared spectroscopy (FTIR) analysis that the PMMA's ester group degrades in a two‐step process resulting in a scission of the whole side chain. The formation of the surface structure may result as suggested by Koval8 from a self‐assembled etch mask on the surface that is generated due to the interaction of the plasma particles (ions and photons) with the material in surface‐near regions.…”