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A polymeric photobase generator bearing N-phenylcarbamate groups was prepared to generate aromatic amino groups upon irradiation and used for color imaging on a thin polymer film. Polymer bearing N-phenylcarbamate groups was prepared by copolymerization of methacryloyloxyethyl phenylcarbamate (MPC) and methyl methacrylate (MMA). The photochemical process of the polymer was monitored through the UV and IR absorption spectral analyses and contact angle measurements. Irradiation of the polymer led to the formation of aminobenzoate groups through the photo-Fries type rearrangement or cross-linking through the radical coupling reaction of N-phenylcarbamate groups. The cosinus values of contact angle (θ) of the polymer film decreased upon irradiation indicating that the polymer surface developed a hydrophobic property. A color image was produced by a diazocoupling reaction of the aminobenzoate groups which were produced in the irradiated area of the polymer film with phenolic or aromatic amino coupling agent. The yellow color was developed by resorcinol or aniline treatment, whereas the red color was produced by the naphthol AS or 1-naphthylamine treatment.

A polymeric photobase generator containing oxime-urethane groups is applied to a fluorescence micropatterning material. Polymer bearing oxime-urethane groups was prepared by copolymerization of methyl methacrylate with methacryloyloxyethyl benzophenoneoxime urethane (MBU). The reaction of amino groups in the irradiated copolymer film with dansyl chloride (Dns-Cl) was monitored by using UV absorption, IR absorption and fluorescence spectroscopy. The fluorescence spectrum of the Dns-Cl-treated irradiated copolymer film shows a strong fluorescence with a fluorescence maximum wavelength at 510 nm. A blue fluorescent micropattern with a line width of was obtained. Treatment of the irradiated copolymer film with Dns-Cl and rhodamine B mixture led to the formation of green, red, and orange-colored fluorescence micropatterns. Thus, various colored micropatterns on a single polymer film can be obtained by selective excitation of each dye molecules.

An anti-fouling hybrid material composed of sol–gel-based material and polymer containing phosphorylcholine groups (PMB) was developed and applied to an optical O 2 sensor. An O 2 sensing dye, tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) chloride (RuDPP) was entrapped in the sol–gel-derived matrices in order to prepare the anti-fouling O 2 sensing membrane, and the effect of the entrapped PMB on the performance of the O 2 sensor was studied. The anti-fouling effect was observed using scanning electron microscopy (SEM) after incubating E. coli on the sol–gel-derived sensing membrane. The efficiency of the O 2 sensing membrane in the absence and presence of PMB was compared through the measurement of the fluorescence quenching rate constant of RuDPP in the sensing membrane by dissolved O 2 in H 2 O. Reversibility was observed through changes in the fluorescence intensity upon alternate exposure of the sensing membrane to O 2 and N 2 gas. The prepared sol–gel-derived sensing membrane also has good stability and reproducibility. The results indicated that the anti-fouling sol–gel-derived O 2 sensing membranes containing PMB were stable and the performance of the sensor was not affected at all by the entrapped PMB in the sol–gel-derived matrix.

The photo-crosslinking reaction of a polymeric photobase generator containing phthalimido carbamate (PC) groups was studied and applied to the formation of a negative type micropattern. The copolymer containing PC groups was prepared through the polymerization of methyl methacrylate and phthalimido methacryloxyethylcarbamate (PMC). The photochemical and cross-linking reaction of the copolymer film were studied using the UV and IR absorption spectral changes along with the normalized thickness measurements upon irradiation. The copolymer film was effectively cross-linked upon irradiation with 254 nm UV light, and the cross-linking reaction progressed further with increasing irradiation dose and the amount of PMC units in the copolymer. The photochemical formation of the isocyanato groups was evidenced by comparing the IR absorption spectral changes of the exposed and masked copolymer film. The photo-crosslinking reaction of the copolymer was further studied by using a model compound. The results indicated that the cross-linking reaction occurred because of the formation of urea-type chemical bonds, which were produced through the reaction of the photochemically produced isocyanato and amino groups in the copolymer. A negative micropattern was obtained by using the photo-crosslinking reaction.

A fluorescent micropattern in a thin polymer film is fabricated via a photo-anilide rearrangement of anilide groups in the polymer. Polymer bearing anilide groups are prepared by polymerization of N-phenyl methacrylamide (PMA) and methyl methacrylate. The photo-anilide rearrangement of the prepared polymer and the reaction of the produced amino groups with fluorescamine, are studied by using UV and IR absorption spectroscopy. The fluorescence spectrum of the fluorescamine-treated irradiated polymer film shows a strong fluorescence in the range of ≈420–620 nm with a fluorescence maximum at 496 nm. The patterns exhibited very distinct fluorescence images in the colors of dark blue, sky blue, green, yellow, and red depending on the observed wavelength ranges.

A new cyclic, hindered amine light stabilizer (HALS) was prepared by the addition polymerization of a diepoxide and 4-amino-2,2,6,6-tetramethylpiperidine, and its photostabilizing effects on styrenic polymers were examined. The chemical structure of cyclic HALS was characterized by MALDI-TOF mass spectrometry. The prepared cyclic HALS had a moderate molecular weight (\( \overline M _w \) = 900∼1,100) and high thermal stability (Td ≈ 300 °C) that were compatible with styrenic polymers, such as polystyrene and styrene-butadiene rubber. The photostabilization effect of cyclic HALS was similar to or better than that of Tinuvin 770, a commercially available polymeric HALS. A synergistic effect between cyclic HALS and a UV absorber on the inhibition of photo-oxidation was observed.

In order to develop a one-component photo-curing system for epoxy resin, the photo-crosslinking reactions of the diglycidyl ether of bisphenol A (DGEBA) in the presence of a multifunctional photobase generator (PBG) containing oxime–urethane groups were studied. The cross-linking of DGEBA films and adhesion properties of DGEBA formulations containing the PBG and benzophenone increased with irradiation dose, post-exposure baking (PEB) time, PEB temperature, and the number of oxime–urethane groups in the PBG. A synergistic effect was observed between the PBG and a base amplifier on the film cross-linking of DGEBA. A trifunctional PBG containing oxime–urethane groups was found to be the most efficient PBG in terms of the photo-crosslinking and adhesion properties of the DGEBA-based formulations. Moreover, the devised formulations, including the PBG and benzophenone, were stable for at least 1 month at room temperature. The photocuring system developed in this study appears to offer a one-pack epoxy resin curing system with practical useful properties. Copyright © 2009 John Wiley & Sons, Ltd.

Bicolor fluorescent micro-patterns in the polymer film are prepared through the use of a new group of photobase generator containing phthalimido carbamate groups. The photobase generation from phthalimide carbamates is studied by examining the changes in pH, fluorescence intensity, and photo-crosslinking of poly(glycidyl methacrylate). The product analysis of a model compound indicates that amine groups are produced from the photolytic cleavage of the C–N bond of the phthalimide carbamate groups. A copolymer containing phthalimide carbamate groups is applied to a bicolor fluorescent imaging material. Red-yellow fluorescent micropatterns are obtained by treating the copolymer film, which is irradiated with 254 nm UV light through a photomask, with fluorescamine and rhodamine, consecutively. Various colored fluorescent micropatterns – green, red, or red-yellow, are obtained on a single polymer film by varying the excitation wavelength.

Epoxy polymers containing phosphorylcholine (PC) groups were prepared by the copolymerization of glycidyl methacrylate and 2-methacryloyloxyethyl phosphorylcholine (MPC), and used as a coating material for an oxygen sensing membrane, in order to protect it against bio-fouling by microorganisms. The copolymers had good film forming properties. The cured polymer films had excellent adhesion properties and were transparent at the wavelength of more than 300 nm. The cross-linking reaction of the polymer films increased with increasing amount of MPC units in the copolymer, and the addition of an aliphatic diamine significantly enhanced the cross-linking reaction of the copolymer films. The cured epoxy copolymers show a high anti-fouling effect, which was observed by incubating E. coli on the copolymer films. The coatings of the cured epoxy copolymer did not interfere with the performance of the optical oxygen sensing membrane. Thus, the epoxy copolymers containing PC groups are very useful as an anti-fouling coating material for the optical biosensing membranes.

The chemical structure of a semi-aromatic polyimide-I, which was prepared by the chemical imidization of cyclopentanetetracarboxylic dianhydride and 2,2-bis(4-aminophenyl)hexafluoropropane, was characterized by13C-NMR spectroscopy. The chemically imidized polyimide-I was used for the preparation of a photosensitive polyimide (PSPI)|through the addition of benzophenone and benzophenone oxime hexamethylene diurethane (BOHD), a photobase generator containing oxime-urethane groups. The polyimide-I film containing benzophenone and BOHD was not soluble in 2.38 wt% tetrabutylammonium hydroxide solution in H2O. However, it became soluble following irradiation with 310 nm UV light. A positive tone image with a resolution of 5 μm was obtained with this PSPI, having sensitivity (Dc)|of 1.2 J/cm2 and contrast (γp)|of 1.08. Thus, a polyimide, which is not intrinsically photosensitive, can become photosensitive through the addition of a photobase generator containing oxime-urethane groups as a photosensitive compound.

For their application as one-component photoresists, we prepared epoxy terpolymers containing oxime-urethane and benzophenone groups by the radical polymerization of glycidyl methacrylate (GMA), methacryloxyethyl benzophenoneoxime urethane (MBU), andN-(4-benzoyl)phenylmaleimide (BPMI). The terpolymer composition was optimized to provide the most photosensitive photoresist. The photo-decomposition reaction of the oxime-urethane groups in the terpolymer was monitored by UV absorption spectroscopy, and the photo-crosslinking reaction of the epoxy terpolymer was observed by measuring the normalized thickness. The photosensitivity of the epoxy terpolymer increased as the amount of BPMI and MBU units increased up to 16 and 24 mol%, respectively. Among the terpolymers we prepared, terpolymer T-II(contents of GMA, MBU, BPMI are 75, 19, 6.1 mole%, respectively) exhibited the highest photosensitivity (Dc0.5=430mJ/cm2) and had a moderate contrast (γp = 1.23). Negative-tone micropatterns having a line width of ca. 10 μm were obtained by developing the system with chloroform.

A polymeric photobase generator containing oxime–urethane groups was prepared by copolymerization of methyl methacrylate and methacryloxyethyl benzophenoneoxime urethane, and its photo and thermal crosslinking reaction after irradiation was examined from the measurement of UV and IR absorption spectral changes, insoluble fraction, and molecular weight changes. The photo-crosslinking reaction of the copolymer film was more efficient when irradiations were carried out with 310 nm UV light in the presence of benzophenone than with 254 nm UV light without the addition of benzophenone. The crosslinking reaction increased after postexposure baking (PEB), and this thermal crosslinking reaction mechanism was studied from the identification of the photolysis products of a model compound, benzophenoneoxime phenylurethane, by a high-performance liquid chromatography. The results indicate that the thermal crosslinking reaction of the copolymer after PEB is due to the formation of urea-type chemical bonds. Resist properties of the copolymer were examined from the measurement of normalized thickness and micropattern development. A negative tone image with a resolution of 2 μm was obtained with this copolymer, having a sensitivity (D) of 1200 mJ/cm2 and contrast (γn) of 1.31, when irradiation was carried out with 310 nm UV light in the presence of benzophenone following chloroform development. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 975–984, 2004

Yong Woon Kim, and Taek Hyeon KimFaculty of Applied Chemistry and The Polymer Science & Technology Research Center,Chonnam National University, Gwangju 500-757, KoreaReceived February 19, 2002Key Words : Anthracene polymer, Photoresist, Photo-crosslinkingPhotoresists are very important materials for the photo-fabrication process. They are widely used for the manu-facture of microelectronics, printed circuit boards, silkscreen printing, optical disks, black matrix of color cathod-ray tubes, and so on. They can be classified into two types onthe basis of the solubility changes upon irradiation with UVlight, i.e., positive or negative types. The negative type ofphotoresist is generally more sensitive than the positive one. It is well known that anthracene or its derivatives dimerizephotochemically to give [4+4] cycloadducts across the 9,10-positions of anthracene

A water-developable negative photoresist based on the photocrosslinking of N-phenylamide groups was prepared by the copolymerization of 4-styrenesulfonic acid sodium salts (SSS) with N-phenylmethacrylamide (copolymer A) or p-hydroxy-N-phenylmethacrylamide (copolymer B), and its properties such as solubility changes, photochemical reaction, and photoresist characteristics were studied. The copolymer containing a relatively higher amount of SSS units was soluble in water. Solubility changes of the copolymers in the various buffer solutions of pH 4 ∼ 11 and in water upon irradiation were observed by the measurement of insoluble fraction. The copolymers were soluble in water before irradiation, whereas they became insoluble upon irradiation with the UV light of 254 nm. The photochemical reaction of the copolymer studied by the UV and IR absorption spectroscopies indicated that a photo-Fries rearrangement was favored for copolymer A, whereas a photocrosslinking reaction was predominate for copolymer B. Resist properties of the copolymers were studied by measurement of the normalized thickness and by development of the micropattern. Negative tone images with a resolution of 1 μm were obtained with these materials that have a sensitivity (D) of ∼ 1100 mJ/cm2 with an aqueous developing process.© 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1172–1180, 2002

Copolymers containing oxime-urethane groups were prepared by the copolymerization of methyl methacrylate and benzophenoneoximinocarbonylaminoethyl methacrylate (BCM), and their photochemical properties were examined from the UV and IR absorption spectral changes. The decomposed fraction of oxime-urethane groups in the copolymer increased with irradiation time, but it decreased with the content of BCM units in the copolymer. Changes of the surface properties of the copolymer film on irradiation were studied by measurements of the contact angle and dyeing with an acid dye. The surface of the copolymer film changed to become more hydrophilic upon irradiation with 254 nm of UV light. After the irradiated copolymer films were treated with HCl or methanol, changes of the contact angle of water on irradiation were compared. The copolymer film was dyed by acid dyes after treatment of the irradiated film with HCl. The degree of dyeing increased with irradiation time and BCM units in the copolymer, but it was unaffected by the film thickness. Various colors were developed on the irradiated area depending on the acid dye as the developer. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1200–1207, 2002

A linear epoxide–amine type of a new polymeric HALS was prepared by an addition polymerization of 2,2-bis(4-glycidyloxyphenyl)propane and 4-amino-2,2,6,6-tetramethylpiperidine (ATMP) in chlorobenzene. Two types of addition polymers, high molecular weight HALS (HMH) and low molecular weight HALS (LMH) were isolated by precipitation in acetone. The structure of HMH was characterized from the NMR and MALDI-TOF spectra. The effects of the reaction conditions on the yield of HMH and LMH were observed by varying the reaction conditions such as monomer concentration, reaction temperature, and reaction time. The yield of HMH increased with the amount of the ATMP concentration, reaction temperature, and reaction time. HMH is fairly miscible with polypropylene (PP), polystyrene (PS), and styrene–butadiene rubber. The photostabilizing effect of HMH on the photooxidation of PP and PS at 254 or 310 nm was studied from the UV and IR absorption spectral changes. The results indicate that the photostabilization effect of HMH was similar to or better than that of Cyabsorb UV-3529, a commercially available polymeric HALS.

Various bicolored fluorescent micropatterns are fabricated on a single polymer film by concurrent photobleaching and a photobase generation process. A polymer, bearing anthracene and oxime-urethane groups, is dyed with rhodamine B isothiocyanate after irradiation with 310-nm UV light. The photochemical reaction of the polymer is monitored by UV, IR absorption, and fluorescence emission spectroscopy. Differently colored fluorescent micropatterns are obtained by selectively exciting each dye moiety. Various bicolored fluorescent micropatterns are observed through varying the excitation wavelength and observation wavelength ranges using a confocal microscope. This bicolored fluorescence patterning method will be useful to apply in photonic/electronic devices.

Two 1,2-diketones, 1-phenyl-1,2-propanedione (PD) and 2,3-butanedione (BD) were investigated as new visible light photosensitizers for formulating a dental resin composite of bis-GMA in order to improve the physical properties of the resin composite. The results were then compared with those of camphorquinone (CQ), the most widely used photosensitizer. Photodecomposition of the photosensitizers with and without amine was studied through UV absorption spectroscopy. The photopolymerization efficiency of bis-GMA containing the photosensitizer increased with irradiation time and with the amount of photosensitizer. The increase was in the order: BD

Temperature gradient interaction chromatography (TGIC) analysis of polyisoprene (PI) is reported. PI can be fractionated in terms of molecular weight with high resolution by TGIC using a C18 bondedd silica column as the stationary phase and a mixture of CH 2 Cl 2 /CH 3 CN (80/20. v/v as the mobile phase. The temperature was increased during the elution from 5°C to 34°C to optimize the fractionation of high molecular weight PI. The relatively poor resolation in the low molecular weight range was improved by changing the eluent composition. For example, all the oligomeric species from the unimer to the 29mer of a low molecular weight PI (average mol. wt.: 900) were fully resolved with the mixed eluent of CH 2 Cl 2 / CH 3 CN (50/50, v/v) and a linear temperature program from 6°C to 40°C. In addition, simultaneons site exclusion chromatography and TGIC fractionation of PI/polystyrene, PI/poly(methylmethacrylate) mixtures are also reported.

A monomeric antioxidant (3) was prepared by reacting 3,5-di-tert-butyl-4-hydroxybenzyl alcohol (1) with N-[4-(chlorocarbonyl) phenyl] maleimide (2). This reactive antioxidant was grafted onto polyethylene (PE) by melt processing with free-radical initiators in a mini-max molder. The IR spectra of the grafted PE showed that the monomeric antioxidant was introduced onto the PE. IR spectroscopic methods and titration were used for the quantitative determination of the extent of grafting of the monomeric antioxidant. Also, the extent of crosslinking was indicated by the gel content. Grafting occurred in the following order: dicumyl peroxide (DCP) > benzoyl peroxide > 2,2′-azobisisobutyronitrile. The influences of the DCP concentration and monomeric antioxidant on the extent of grafting were studied. The effects of the reaction time and temperature were also determined. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2968–2973, 2000

The photochemical and photophysical phenomena of dibenzophenoneoxime hexamethylenediurethane have been investigated with laser flash photolysis to understand its participating mechanism in polymer curing reactions. Owing to the extremely short lifetimes of the first excited singlet (22 ps) and triplet (10 ns) (n, π * ) states, that the molecules undergo, with a small quantum efficiency of 10 −4 , decarboxylation at the lowest triplet state with the rate constant of 10 6 s −1 , forming dehydrogenated iminyl and aminyl radicals. Abstracting a hydrogen atom in the time scale of 270 μs, the iminyl radical converts mainly into diphenyl-1-imine which, with being irradiated, dehydrogenates and dimerizes to yield benzophenone azine. Meanwhile, the aminyl radical abstracts H to generate benzophenoneoxime-urethanyl hexamethyleneamine, which, as a photobase, raises solution pH.

Photochemical base formation from oxime-urethane derivatives was observed via pH changes, GC and HPLC analysis, and laser flash photolysis study. Photolysis of these derivatives results in the formation of amines which induce cross-linking of poly(glycidyl methacrylate) (PGMA) upon heating. Photocross-linking reaction of the copolymers, containing epoxy and oxime-urethane groups, were studied by measuring the insoluble fraction of copolymer films under various reaction conditions. Thermal cross-linking reaction of the copolymer was catalysed by the photogenerated pendant amines. The copolymer containing oxime-urethane groups which photogenerate aromatic amines can be utilized as an image recording material.

N-[4-(Azidocarbonyl)phenyl]maleimide (3) and N-[4-(N′-phenoxycarbonylamino)phenyl]maleimide (5) were polymerized and copolymerized with methyl methacrylate (MMA) or acrylic acid (AA) by initiation with AIBN. The resultant polymers were to have aromatic isocyanato groups when heated. In the differential scanning calorimetry measurement, the polymers from monomer 3 showed a strong and broad exotherm around 130°C. Thermogravimetric analysis also showed a weight decrease corresponding to the elimination of nitrogen at that temperature. The formation of isocyanato groups was confirmed by infra-red measurement with varying the cell temperature. The coupling reaction of the polymer with N-4-(nitrophenyl)- L -prolinol, resulting in the formation of urethane bonds, was carried out in a quantitative yield. The crosslinked films from copolymers of 5 and MMA or AA were obtained when heated above 200°C. The cured films were insoluble in common organic solvents. With the copolymers with AA it was expected that carboxylic groups would react with isocyanato groups generated from urethane units when heated. The copolymer was degraded above 150°C. After curing, its thermal stability improved dramatically, no weight loss being observed up to 300°C.

Copolymers containing epoxy and oxime-urethane groups were prepared by copolymerization of glycidyl methacrylate (GMA) and benzophenone oxime allylurethane (BAU). The physical properties of these copolymers were characterized by GPC, NMR and DSC analyses. Photo-crosslinking reaction of the copolymers were studied by measuring the insoluble fraction of copolymer films under various reaction conditions. The degree of cross-linking reaction increased with irradiation time, heating temperature and the amount of BAU units in the copolymer. UV and IR absorption spectral studies indicate that thermal cross-linking reaction of the copolymer was catalyzed by the pendant photogenerated amines.

Two oxime-urethane derivatives, benzophenone oxime N-cyclohexylurethane (1) and dibenzophenone oxime N,N′-hexamethylenediurethane (2), were used as photobase generators. Photolysis of these derivatives results in the formation of amines which induce cross-linking of poly(glycidyl methacrylate) (PGMA) upon heating. The bifunctional derivative 2 is more efficient than the monofunctional derivative 1 in inducing thermal cross-linking of PGMA, with a maximum degree of insolubilization increasing up to ca. 90%.

Bicolor fluorescent micro-pattern in the polymer film was prepared through the use of a new group of photobase generator containing phthalimido carbamate groups. The photobase generation from phthalimide carbamates was studied from the product analysis of a model compound. The result indicates that amine was produced from the photolytic cleavage of the CN bond of the phthalimide carbamate group. Bicolor fluorescent micropatterns were obtained by treating a copolymer film containing phthalimido groups, which was irradiated with 254 nm UV light through photomask, with fluorescamine and rhodamine, consecutively. Various colored fluorescent micropatterns – green, red, or red-yellow, were obtained on a single polymer film by varying the excitation wavelength.

The nanosecond laser flash photolysis of 1,2-bispyrazylethylene indicates that an efficient intersystem crossing occurs on direct excitation. The triplet energy level of the trans isomer lies close to 39.0 kcal mol −1 and that of the cis isomer lies between 35.1 and 39.0 kcal mol −1 . The triplet-triplet absorption maximum of the trans isomer is blue shifted and the absorption spectra show fine structure because of the change of the energy gap between the 3 (n,π * ) and the lowest 3 (π,π * ) state as the polarity of the medium increases. The triplet lifetime of the trans isomer (160 ns) directly measured by laser flash photolysis also indicates that the direct photo-isomerization of this compound proceeds through the triplet manifold in contrast to the behaviour observed for stilbene.

— C4--Photocycloaddition of 5,7-dimethoxycoumarin (DMC) to thymine (λ≥ 300 nm) was studied in dioxane-water solution, in aqueous frozen state, and solid film state. The major product was isolated and characterized by physical methods. Elemental analysis data, spectral analyses, and photo-splitting of the product indicate the product to be a 1:l C4--cycloadduct of DMC and thymine.