Surface Modification Of Polystyrene Research Articles

Surface modification of polystyrene by blending substituted styrene copolymers

The surface modification of polystyrene (PS) by the blending of 4-acetoxystyrene polymers and their corresponding hydrolysis products, 4-hydroxystyrene polymers, was investigated on the basis of X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and contact-angle measurements. According to XPS and AFM measurements, when polystyrene-block-poly(4-acetoxystyrene) (PS-b-PAS) or polystyrene-block-poly(4-hydroxystyrene) (PS-b-PHS) was incorporated into PS, the block copolymer was preferentially segregated at the highest surface region of the blend. This segregation increased to a plateau value when more than 5 wt % of either PS-b-PHS or PS-b-PAS was added. The contact angle of the modified PS by PS-b-PAS or PS-b-PHS was slightly lower than that of homopolystyrene, but no further decrease was observed with the blend ratio of the diblock copolymer increasing from 5 to 20 wt %. For a PS/PS-b-PHS blend, the surface atomic concentration ratio O/C increased linearly with the molecular weight of poly(4-hydroxystyrene) blocks in diblock copolymer PS-b-PHS in the range of our study. The different structures of 4-acetoxystyrene polymers and their hydrazinolyzed materials may affect the surface compositions of their blends with PS; among these polymers, PS-b-PHS and PS-b-PAS appeared to be most effective. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 1046–1054, 2001

Surface modification of polystyrene by blending substituted styrene copolymers

AbstractThe surface modification of polystyrene (PS) by the blending of 4‐acetoxystyrene polymers and their corresponding hydrolysis products, 4‐hydroxystyrene polymers, was investigated on the basis of X‐ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and contact‐angle measurements. According to XPS and AFM measurements, when polystyrene‐block‐poly(4‐acetoxystyrene) (PS‐b‐PAS) or polystyrene‐block‐poly(4‐hydroxystyrene) (PS‐b‐PHS) was incorporated into PS, the block copolymer was preferentially segregated at the highest surface region of the blend. This segregation increased to a plateau value when more than 5 wt % of either PS‐b‐PHS or PS‐b‐PAS was added. The contact angle of the modified PS by PS‐b‐PAS or PS‐b‐PHS was slightly lower than that of homopolystyrene, but no further decrease was observed with the blend ratio of the diblock copolymer increasing from 5 to 20 wt %. For a PS/PS‐b‐PHS blend, the surface atomic concentration ratio O/C increased linearly with the molecular weight of poly(4‐hydroxystyrene) blocks in diblock copolymer PS‐b‐PHS in the range of our study. The different structures of 4‐acetoxystyrene polymers and their hydrazinolyzed materials may affect the surface compositions of their blends with PS; among these polymers, PS‐b‐PHS and PS‐b‐PAS appeared to be most effective. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 1046–1054, 2001

負イオン注入によるポリスチレン表面の神経細胞接着特性の改質とパターン化処理

Modification of polystyrene surface by negative ion implantation for improving and patterning attachment properties of neurons was investigated. This modification technique is required for artificial formation of neural network with neuron cells and for development of “bio-interface” between vital neural system and external silicon circuit. Silver-negative ions were implanted into various kinds of polystyrene surfaces through a mask with slit array of 60μm in width and 4 mm in length with 60μm spacing. In the cell culture of PC-12h (rat adrenal pheochromocytoma) cells with the ion-implanted polystyrenes, PC-12h cells attached and neurites extended only on the ion-implanted regions of untreated polystyrene dishes (NTPS) and spin-coated polystyrene (SCPS). This means that pattering ion implantation is able to make patterning treatment both of cell attachment and neurites extension properties.

An In Situ Comparison between VUV Photon and Ion Energy Fluxes to Polymer Surfaces Immersed in an RF Plasma

Absolutely calibrated vacuum ultraviolet (VUV) spectroscopy has been used to determine the energy fluxes of VUV photons at an electrically floating substrate in a low-pressure 13.56-MHz radiofrequency plasma reactor used for polymer surface treatments. These fluxes have been compared with the positive ion flux that was reported in an earlier study. At the typical operating parameters of 10-mTorr pressure and 10-W power, the total VUV energy flux is 2.2 mW cm-2, compared with a value of 3.3 mW cm-2 from the ions. With increasing power (from 0.5 to 12 W), both the ion and VUV energy fluxes increase monotonically. However, as the pressure increases, (1−100 mTorr), the ion energy flux declines, while the VUV component increases. At discharge powers of 10 W, and pressures greater than 25 mTorr, the greater part of the energy flux to the surface is from the VUV photons. These measurements are used to determine which of the plasma components, VUV or ions, will be most effective in the treatment of polystyrene surfaces in a pure Ar plasma. Because of the low VUV absorption coefficient of polystyrene most of the photon flux penetrates through the outermost 2 nm of the polymer surface without attenuation. Consequently, we calculate that under typical plasma operating parameters, the ions play the major role in the modification of polystyrene surfaces because of their shorter stopping distances.

Surface modification of polystyrene by photoinitiated introduction of cyano groups

The surface of polystyrene was modified by the introduction of CN groups. This was achieved by irradiating the polymer with UV light (254 nm) in the presence of gaseous cyanogen bromide (BrCN). X-ray photoelectron spectroscopy (XPS) and FTIR analysis showed that after irradiation both Br and CN groups were covalently bound to the polymer surface. Quantitative XPS analysis revealed that upon prolonged irradiation every second monomer unit at the surface was modified with a CN group. It was demonstrated that photochemical techniques can be employed to attach specific functional groups onto polymer surfaces.

Surface modification of polystyrene by photoinitiated introduction of cyano groups

The surface of polystyrene was modified by the introduction of CN groups. This was achieved by irradiating the polymer with UV light (254 nm) in the presence of gaseous cyanogen bromide (BrCN). X-ray photoelectron spectroscopy (XPS) and FTIR analysis showed that after irradiation both Br and CN groups were covalently bound to the polymer surface. Quantitative XPS analysis revealed that upon prolonged irradiation every second monomer unit at the surface was modified with a CN group. It was demonstrated that photochemical techniques can be employed to attach specific functional groups onto polymer surfaces.

Relation between hydrophilicity and cell culturing on polystyrene Petri dish modified by ion-assisted reaction

Polystyrene Petri dishes were modified by an ion-assisted reaction to supply a suitable surface for culturing cells. Wettability was measured by a contact anglometer after surface modification of polystyrene. Contact angles of water on the polystyrene were not reduced much by Ar+ ion irradiation only, but dropped rapidly to a minimum of 19°, when polystyrene surface was modified by Ar+ ion irradiation with flowing oxygen gas. X-ray photoelectron spectroscopy analyses showed that hydrophilic groups were formed on the surface of polystyrene by a chemical reaction between unstable chains induced by the ion irradiation and the blown oxygen gas. Newly formed hydrophilic groups were identified as CO, (CO) and (CO)O bonds. The influence of the ion beam modification in growth of the rat pheochromocytoma cells was investigated. The results showed exclusively preferential cell growth in the polystyrene Petri dish that was treated by the ion-assisted reaction. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 41–46, 1999

Surface Modification of Polystyrene by Gamma-Radiation

The effect of gamma-radiation on the surface chemical properties of polystyrene was studied by ESCA and FT-IR. Gamma-radiation produces surface >C=O and C-O containing functional groups only, and also causes oxidation to depths >10 nm as detected by ESCA. FT-IR spectra showed that below the top few molecular layers ester, acid, and carbonyl groups of various types were present. The α,β-unsaturated carbonyl/acid groups form a higher proportion of the total carbonyls with increasing depth. Surface oxidation follows pseudo-first-order kinetics; the extent of interior oxidation is linear with dose.