Simple Patterning of Cells on a Biocompatible Nonchemically Amplified Resist

Summary: A simple lithographic process in conjunction with a novel biocompatible nonchemically amplified photoresist material was successfully used for cell patterning. UV light irradiation on selected regions of the nonchemically amplified resist film renders the exposed regions hydrophilic by the formation of carboxylic groups. Mouse fibroblast cells were found to be preferentially aligned and proliferated on the UV light exposed regions of the nonchemically amplified resist film where carboxylic groups were present.

Schematic representation of the simplified lithographic process used for cell patterning.     

Crystal‐to‐Crystal Photoinduced Electron Transfer Generating Photoacids to Formulate Water‐Borne Photopolymers

Casting a photopolymer solution to form a film, followed by imagewise photoirradiation and subsequent wet development, leads to photolithography. Whereas the wet development is achievable with aqueous alkali, the emission of an organic solvent as a volatile organic compound (VOC) is usually inevitable during the film casting because ingredients of common photopolymers are insoluble in water. We show here a prototype of water‐borne photopolymers dispersed with milled nanoparticles of poorly water‐soluble photoacid generators (PAGs), which undergo solid‐state photolysis to liberate a photoacid to make a poly(vinyl alcohol) film insoluble in water with the aid of an acid‐sensitive crosslinking reagent. The photolysis of onium‐type PAGs is sensitized in the solid state simply by comilling with water‐insoluble sensitizers to extend spectral sensitivity of this kind of photopolymers. Fluorescence quenching measurements revealed that the solid‐state sensitization occurs through exciton migration in sensitizer particles followed by electron transfer to PAG particles.

     

偏苯三酸酐-环氧丙烷丁基醚合成超支化碱溶性聚酯

通过1,2,4-偏苯三甲酸酐(TA)和环氧丙烷丁基醚(BGE)合成超支化碱溶性聚酯,利用合成聚合物分子外围的羧基与烯丙基缩水甘油醚(AGE)反应,在超支化聚合物分子外围引入反应性烯丙基醚.研究了树脂组成对感光性和碱溶性的影响;结果表明:调整反应物料配比,可以获得较好的碱溶性和光固化性能,其树脂的反差γ可达到3.92.     

Characterization of Rubber Epoxy Blends by Thermal Analysis

Differential scanning calorimetry (DSC), thermogravimetric analysis (TG) and dynamic mechanical analysis (DMA) of the blends ofepoxy cresol novolac (ECN) resin toughened with liquid carboxy terminated butadiene-co-acrylonitrile (CTBN) rubber have been carried out. Exothermal heat of reaction (ΔH) due to crosslinking of the resin in presence of diaminodiphenyl methane(DDM, as amine hardener) showed a decreasing trend with increasing rubber concentration. Enhancements of thermal stability as well as lower percentage mass loss of the epoxy-rubber blends with increasing rubber concentration have been observed in TG. Dynamic mechanical properties reflected a monotonic decrease in the storage modulus (E′) with increasing rubber content in the blends. The loss modulus (E″) and the loss tangent(tanδ) values, however, showed an increasing trend with rise of the temperature up to a maximum (peak) followed by a gradual fall in both cases. Addition of 10 mass% of CTBN resulted maximum E″ and tanδ. This revised version was published online in July 2006 with corrections to the Cover Date.     

Fundamental investigation on interaction between hexafluoroisopropylalcohol‐containing styrene and photochemical acid generator for rationale design of photoresist system

This article presents the effect of some ionic photochemical acid generators (PAGs) to inhibit the dissolution of hexafluoroisopropylalcohol (HFA)‐containing polystyrene to an aqueous alkaline developer, which is a highly important effect in photoresist application to enhance resolution of patterning. The dissolution inhibiting factors and mechanisms were investigated by evaluating the solubility and the ¹H‐NMR analysis of OH proton in HFA moiety. The dissolution inhibition effect was enhanced when the structures of PAGs fulfill some requirements: (a) their anions should have higher basicity and smaller van der Waals volume; (b) their cations should be stabilized by conjugation with electron‐rich aromatics. In the dissolution inhibition, the HFA moiety interacts with the anionic part of PAGs liberated from the electrostatic interaction with the counter cation. These interactions were predicted and quantified by DFT calculations using Gaussian 09, leading to the rational designs of PAGs with higher dissolution inhibiting effect in photoresist systems. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 531–538     

Characterization of photoresists for ArF‐excimer laser lithography using monoenergetic positron beams

The volume and depth distributions of open spaces in photoresist films designed for ArF‐excimer laser light exposure were studied with monoenergetic positron beams. We measured the Doppler broadening spectra of the annihilation radiation and lifetime spectra of positrons for acrylate and cyclic olefin‐co‐maleic anhydride (COMA) polymers spin‐coated onto Si wafers with methyl amyl ketone, cyclohexanone, and propylene glycol methyl ether acetate solvents. The volume of open spaces in both prebaked acrylate and COMA films was estimated to be 0.12 nm³. The volume of open spaces in acrylate films decreased up to 20% by postexposure baking, but no large change was observed for COMA films. The decrease in the open volume was attributed to the removal of large molecules (adamantyl) from flexible main chains after the chemically amplified reaction of acrylate. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 341–346, 2004     

Synthesis and characterization of negative‐type photosensitive hyperbranched polyimides with excellent organosolubility from an A2 + B3 monomer system

A series of photosensitive hyperbranched polyimides (HB‐PIs) were prepared through facile end‐group modifications of the fully imidized polymer. A triamine, 1,3,5‐tris(4‐aminophenoxy)benzene, and a dianhydride, 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride, were condensed with a dropwise addition method in a molar ratio of 1/2 to afford an anhydride‐terminated poly(amic acid) precursor, which was then end‐capped by 4‐aminophenol and chemically imidized to yield a phenol‐terminated HB‐PI. The modifications of the terminal phenol groups of the polyimide by acyl chloride compounds (acryloyl chloride, methylacryloyl chloride, and cinnamoyl chloride) gave the target polymers. The photosensitive HB‐PIs showed good thermal properties and excellent solubility even in low‐boiling‐point solvents at room temperature, such as acetone, 1,1,2‐trichloroethane, tetrahydrofuran, and chloroform. Photosensitive property studies revealed good photolithographic properties with a resolution greater than 3 μm and a sensitivity of 650–680 mJ/cm². © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1735–1744, 2004     

Modification of Montmorillonite through Intercalative Polymerization

Montmorillonite(MMT) was modified through intercalative polymerization of phenol and formaldehyde catalyzed by oxalic acid.The modified montmorillonite was delaminated at large,as demonstrated by XRD and TEM studies,It can disperse easily in epoxy resion to from exfoliated nanocomposites.The nanoscale silicate platelets dispersed in water can be metallized by silver deposition.     

Photocrosslinking system based on a poly(vinyl phenol)/thermally degradable diepoxy crosslinker blend

Photocrosslinkable systems with thermally cleavable properties based on blends of poly(vinyl phenol) (PVP) and diepoxides were investigated. Thermally cleavable diepoxides as crosslinkers were prepared and characterized. As a thermally cleavable linkage, a tertiary ester moiety was incorporated into the crosslinker molecule. PVP/crosslinker blended films containing photoacid generators (PAGs) became insoluble in solvents after UV irradiation and subsequent post‐exposure‐bake (PEB) treatment. With a rise in the PEB temperature, the insoluble fraction of the irradiated films increased, passed through a maximum value, decreased, and increased again at elevated baking temperatures. The insolubilization profiles of the irradiated films were complicated and strongly dependent on the type of PAG used, the structure of the crosslinkers, and the PVP/crosslinker ratio. A mechanism for the thermal degradation was studied with Fourier transform infrared spectroscopy. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3055–3062, 2002     

Base‐amplifying silicone resins with photobase‐generating side chains and their application to negative‐working photoresists

To accomplish high photosensitivity of resist systems including photobase generators, we have proposed the concept of base‐proliferation reactions that generate base molecules in a nonlinear manner by the action of a catalytic amount of base; however, excessive diffusion of generated base molecules is still a problem. We have designed novel functional silicone resins bearing both base‐amplifying units and photobase‐generating units, and synthesized resins with various composition ratios. The synthesized resins are decomposed autocatalytically after UV irradiation and subsequent heating at 100 °C, which indicates progression of base‐proliferation reactions. High photosensitivity (8.1 mJ cm^?2) was recorded, and it was found that the photosensitivity is about 490 times enhanced by replacing a base‐catalytic reaction system with the base‐proliferation reaction system. Furthermore, a 4 × 10 µm line‐and‐space pattern has been successfully fabricated using the silicone resin. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1205–1212