Photolithographic Materials for Novel Biocompatible Lift Off Processes

Douvas, Antonios M.; Diakoumakos, Constantinos D.; Argitis, Panagiotis; Μισιάκος, Κ.; Dimotikali, D.; Mastihiadis, C.; Kakabakos, Sotirios

doi:10.1142/9789812810861_0022

Cited by 22 publications

(38 citation statements)

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“…18, 21,22 To produce a successful coating, the supercritical solvent system must dissolve the block copolymer but not the PS substrate. Polymers with low Tg or low surface tension are prone to dissolution in scCO 2 since their polymer-polymer interactions are weak while the polymer-CO 2 interaction is relatively strong.…”

Section: Resultsmentioning

confidence: 99%

Fabrication of Block Copolymer Monolayers by Adsorption from Supercritical Fluids: A Versatile Concept for Modification and Functionalization of Polymer Surfaces

Chen

Koberstein

2008

Langmuir

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We describe a generic method for polymer surface modification and functionalization that is applicable for substrates of arbitrary shape. The method involves the deposition of monolayer and submonolayer films of photoactive block copolymers from supercritical fluids. Poly(styrene-b-tert-butyl acrylate), poly(S-b-tBA), block copolymer monolayers form spontaneously on polystyrene substrates by adsorption from scCO2 when hexane is used as a cosolvent. Atomic force microscopy indicates the films are flat and without pores after modification. Ethylene glycol contact angles increase linearly with deposition pressure until a constant value, equal to that of pure P tBA, is attained at pressures of 18 MPa or greater at 40 degrees C. This trend mimics the change in block copolymer solubility with pressure and indicates that the block copolymer self-assembles and orders at the surface, presenting a P tBA layer at the air interface with the PS block orienting toward the PS substrate. The P tBA layer thickness, determined by angle dependent X-ray photoelectron spectroscopy, reaches a saturated monolayer value of ca. 2 nm for pressures of 18 MPa and higher, consistent with the thickness expected for unperturbed PtBA chains comprising a wet brush. This concept for polymer surface modification initially produces a hydrophobic surface due to surface adsorption of the low surface tension PtBA block, but can also be used to prepare hydrophilic, functional surfaces, either modified or patterned with carboxylic acid groups, by photolytic or acid catalyzed deprotection/hydrolysis of the tert-butyl ester groups.

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Section: Resultsmentioning

confidence: 99%

Fabrication of Block Copolymer Monolayers by Adsorption from Supercritical Fluids: A Versatile Concept for Modification and Functionalization of Polymer Surfaces

Chen

Koberstein

2008

Langmuir

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“…45,46 An optimum concentration can be determined that permits dissolution of the exposed resist and, at the same time, enhanced resolution. The well established biocompatibility of PHEMA homopolymer could be further exploited in the Negative tone imaging.…”

Section: Micropatterning Resultsmentioning

confidence: 99%

“…biomolecule micro-array fabrication, or environmentally friendly lithography. 45,46 In the present paper, both positive and negative imaging chemistries and the micropatterning possibilities offered by using poly(2-hydroxyethyl methacrylate, PHEMA) and poly(2-hydroxypropyl methacrylate, PHPMA) under exposure to UV and electron-beam radiation are explored. Emphasis is given to the elucidation of reaction mechanisms using mass spectroscopy and the relation with imaging chemistries encountered in other poly(methacrylate) homopolymer and copolymer based lithographic materials.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of poly(hydroxyethyl methacrylate) imaging chemistries for micropatterning applications

et al. 2004

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Chemical reactions leading to imaging of poly(2-hydroxyethyl methacrylate) (PHEMA) based materials are investigated. Positive imaging is obtained upon exposure to deep UV and electron beam radiation following a chain scission mechanism. The presence of the OH group adds the possibility of development in alkaline aqueous solutions with considerably higher sensitivities than in the case of PMMA. On the other hand, negative tone lithography can be achieved with the addition of photo-acid generators that induce crosslinking, arising mainly from transesterification reactions. Reaction mechanisms have been investigated mostly by MS studies supported by FTIR and UV spectroscopies. Micropatterning characteristics for deep UV and electron beam radiation have also been evaluated. Submicron patterning capabilities are demonstrated for both positive and negative imaging although higher resolution is hindered by strong swelling phenomena during development. Nevertheless, specific patterning applications including novel schemes for use in biomaterials and microsystems are anticipated.

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“…Block copolymer, P(S-b-tBA) was chosen to modify PS microspheres for several reasons: after deposition, the PtBA block is thermodynamically driven to air-polymer interface via preferential surface segregation because of its lower surface tension，while the PS block interpenetrates with the PS microspheres due to its higher surface tension and identical chemistry with substrate. That is, P(S-b-tBA) acts as surfactant and orders at the modified surfaces; PtBA is expected to be slightly soluble in scCO 2 [24,25] that makes P(S-b-tBA) soluble in scCO 2 with a small amount of organic cosolvent; and finally, it initially offers a tert-butyl ester groups covered hydrophobic surface to satisfy the need of a release surface, but can also generate a hydrophilic one by photolytic or acid catalyzed hydrolysis of the tert-butyl ester groups to carboxyl groups [26] .…”

Section: Results and Disscussionmentioning

confidence: 99%

Functionalizing ps microspheres by supercritical deposition of P(S-b-tBA) for diverse interfacial properties exemplified with biocidal ability

Chen

Teng

2012

Chin J Polym Sci

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Polystyrene (PS) microspheres were functionalized with poly(styrene-b-tert-butyl acrylate) (P(S-b-tBA)) by adsorption from supercritical mixture of CO 2 and hexane. Supercritical deposition formed a shell-core structure that contained a shell of poly(tert-butyl acrylate) (PtBA) blocks and a core of the PS blocks entangling with the PS microspheres. The thickness of the PtBA layer and thereby the areal density of tert-butyl ester groups increased with the deposition pressure until plateau values attained at 20 MPa and higher. The tert-butyl ester groups were hydrolyzed to carboxyl groups for conjugation with tert-butylamine molecules via amide bonds that were further chlorinated into biocidal N-halamine moieties. The functionalization layer and its bonded N-halamine moieties were stable in flowing water and the chlorine could be regenerated upon eventual loss. This functionalization concept is applicable to polymers of any external and internal surfaces to achieve diverse surface properties by varying block copolymer and conjugated moieties.

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Photolithographic Materials for Novel Biocompatible Lift Off Processes

Cited by 22 publications

References 0 publications

Fabrication of Block Copolymer Monolayers by Adsorption from Supercritical Fluids: A Versatile Concept for Modification and Functionalization of Polymer Surfaces

Fabrication of Block Copolymer Monolayers by Adsorption from Supercritical Fluids: A Versatile Concept for Modification and Functionalization of Polymer Surfaces

Evaluation of poly(hydroxyethyl methacrylate) imaging chemistries for micropatterning applications

Functionalizing ps microspheres by supercritical deposition of P(S-b-tBA) for diverse interfacial properties exemplified with biocidal ability

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