The design of chemically amplified imaging systems based on acid catalyzed thermolytic cleavage of polymer main-chains has been exploited with a variety of structures containing tertiary, allylic, or benzylic ester groups. In all cases, the esters have been designed for their ability to undergo facile thermolytic elimination. This report outlines the preparation, study, and imaging of several polyesters containing thermolytically active moieties. These new acid labile polyesters have been incorporated into two-component imaging materials for which radiation sensitivity is due to the presence of compounds which produce acid upon irradiation. The photogenerated acid is then used to catalyze thermolytic cleavage of the polyester main-chain in a process which does not consume the acid and therefore provides for chemical amplification. Imaging is possible using a variety of radiation sources, from deep-UV to X-rays. The concept of imaging through multiple main-chain cleavage is important as it can lead to self- or dry developing images. In the present study, only partial self-development was observed as one of the diacid liberated by the chain cleavage process was not volatile. A second family of radiation sensitive imaging materials has also been designed based on the catalyzed electrophilic crosslinking of polymers containing aromatic rings. While this new approach is only illustrated here for systems in which crosslinking involves polymer pendant groups, the same design is also applicable to polymer main-chains. This family of crosslinkable, chemically amplified, resist materials shows very high sensitivities of ca. 1mJ/cm2 for exposure in the deep-UV, ca. 1μC/cm2 for E-beam exposure, and ca. 12-15mJ/cm2 for X-ray synchrotron radiation.

Polymers containing coumarin and Ru(BpyMe2)32+ chromophores were synthesized using a grafting approach and also a copolymerization approach. It was found that the solubility of polymers made from Ru-containing monomers was higher than that observed for comparable polymers obtained by grafting of Ru complexes onto bpy-containing prepolymers. The resulting bichromophoric macromolecules exhibited enhanced absorption and luminescence properties compared to the single Ru(BpyMe2)32+ complexes due to a very efficient (>95%) energy transfer between the coumarin donor dyes and the ruthenium chromophores. In addition, a novel system in which two different donor dyes are present together with the Ru complex was synthesized and also found to deliver efficient energy transfer to the ruthenium complexes.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSolution and solid-state properties of hybrid linear-dendritic block copolymersIvan Gitsov and Jean M. J. FrechetCite this: Macromolecules 1993, 26, 24, 6536–6546Publication Date (Print):November 1, 1993Publication History Published online1 May 2002Published inissue 1 November 1993https://pubs.acs.org/doi/10.1021/ma00076a035https://doi.org/10.1021/ma00076a035research-articleACS PublicationsRequest reuse permissionsArticle Views685Altmetric-Citations161LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTStimuli-Responsive Hybrid Macromolecules: Novel Amphiphilic Star Copolymers With Dendritic Groups at the PeripheryIvan Gitsov and Jean M. J. FréchetView Author Information Baker Laboratory, Department of Chemistry Cornell University Ithaca, New York 14853-1301 Cite this: J. Am. Chem. Soc. 1996, 118, 15, 3785–3786Publication Date (Web):April 17, 1996Publication History Received18 December 1995Published online17 April 1996Published inissue 1 January 1996https://pubs.acs.org/doi/10.1021/ja9542348https://doi.org/10.1021/ja9542348rapid-communicationACS PublicationsCopyright © 1996 American Chemical SocietyRequest reuse permissionsArticle Views1076Altmetric-Citations189LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Dendrons,Hydrophilicity,Macromolecules,Micelles,Micellization Get e-Alerts

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA new approach to mesophase stabilization through hydrogen bonding molecular interactions in binary mixturesTakashi Kato and Jean M. J. FrechetCite this: J. Am. Chem. Soc. 1989, 111, 22, 8533–8534Publication Date (Print):October 1, 1989Publication History Published online1 May 2002Published inissue 1 October 1989https://pubs.acs.org/doi/10.1021/ja00204a044https://doi.org/10.1021/ja00204a044research-articleACS PublicationsRequest reuse permissionsArticle Views2276Altmetric-Citations601LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Photoinduced crosslinking of polymers through electrophilic aromatic substitution has been achieved with a family of styrenic polymers or copolymers containing both latent electrophiles and activated aromatic groups. These polymers can be used in combination with a photoacid generator to design a non-swelling negative multipurpose resist which can be used for deep-UV, X-ray or E-beam imaging and has a very high sensitivity. For example, in the deep-UV, sensitivities of less than 1 mJ/cm2 are obtained with very high contrasts. Irradiation of the two-component resists results in the generation of strong acid which, upon baking, activates the latent electrophile to a carbocationic species that couples to neighboring activated aromatic moieties in a crosslinking process. Vinyl-phenol units are incorporated in the copolymer formulation to provide activated aromatic sites, solubility of the resist in aqueous base, and lack of swelling during image development. Alternate three-component formulations in which the latent electrophile is separate from the activated aromatic moiety are also suitable.

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Reactive polymers play many roles, from supports for solid-phase synthesis or catalysis to media for separations. Although macroporous polymer beads that provide high reactive capacities and excellent solvent tolerance are well established, approaches to monosized beads with optimized pore structures or multiple chemistries segregated within pores of different sizes have expanded their realm of application. Polymer monoliths containing intricate pore networks can be obtained in any desired shape by a simple molding process and provide unique advantages such as fast kinetics, high reactivity, and high throughput. Applications ranging from immobilized enzyme reactors to fast media for the separation of synthetic or biopolymers are presented.

A family of water-soluble, negative-tone, high-resolution, chemically amplified photoresists based on partially or fully deprotected poly(1,2:5,6-di-O-isopropylidene-3-O-methacryloyl-α-d-glucofuranose) is described. Both the molecular weight of the parent ketal-protected polymer and the extent of its deprotection to a water-soluble polymer containing 3-O-methacryloyl-d-glucopyranose repeat units must be carefully controlled to provide good coating and imaging properties. The two ketal protecting groups of the poly(1,2:5,6-di-O-isopropylidene-α-d-glucofuranose) have different reactivity, and their complete removal requires long reaction times under hydrolytic conditions. The detailed deprotection chemistry of the polymer is readily understood through model studies with the fully and partially protected analogues of the polymer pendant groups: 1,2:5,6-di-O-isopropylidene-α-d-glucofuranose and 1,2-isopropylidene-α-d-glucopyranose. When combined with a water-soluble photochemical precursor of acid such as (4-methoxyphenyl)dimethylsulfonium trifluoromethanesulfonate, films of the deprotected or partially deprotected poly(1,2:5,6-di-O-isopropylidene-3-O-methacryloyl-α-d-glucofuranose) undergo acid-catalyzed cross-linking. The enhanced performance of the partially deprotected polymers over that of poly(3-O-methacryloyl-d-glucopyranose) suggests that the presence of remaining hydrophobic groups that afford water dispersibility rather than full solubility may be key to their performance. Imaged negative-tone features as small as 0.2 μm are obtained with these materials that have sensitivities of ca. 30 mJ/cm2 with wholly aqueous casting and processing.

The porosity and flow characteristics of macroporous polymer monoliths that may be used to prepare separation media, flow-through reactors, catalysts, or supports for solid-phase chemistry can be controlled easily during their preparation. Key variables such as temperature, composition of the pore-forming solvent mixture, and content of cross-linking divinyl monomer allow the tuning of average pore size within a broad range spanning 2 orders of magnitude. The polymerization temperature, through its effects on the kinetics of polymerization, is a particularly effective means of control, allowing the preparation of macroporous polymers with different pore size distributions from a single composition of the polymerization mixture. The choice of pore-forming solvent is also important, larger pores being obtained in a poor solvent due to an earlier onset of phase separation. Increasing the proportion of the cross-linking agent present in the monomer mixture not only affects the composition of the final monoliths but also decreases their average pore size as a result of early formation of highly cross-linked globules with a reduced tendency to coalesce. The synergy of different effects has also been observed under specific polymerization conditions using two monomer pairs, styrene−divinylbenzene and glycidyl methacrylate−ethylene dimethacrylate polymerized in close molds. Mercury intrusion porosimetry measurements, inverse size exclusion chromatography, and back pressure measured at different flow rates with the macroporous monoliths were used for the characterization of the porous properties. A good correlation between pore size and flow resistance that follows the Hagen−Poiseuille equation used previously to describe flow through a straight tube has been found.

Abstract The enantioselective reaction of diethylzinc (II) with the benzaldehydes (I), yielding the alcohols (III), is catalyzed by polymer‐bound chiral amino alcohols.

A novel non-contact method of forming groove servo patterns on optical disk substrates has been demonstrated. The servo forming layer consists of a copolymer of (p-t-butyloxycarbonyloxy)styrene and styrene formulated with an onium salt which photogenerates acidic species upon exposure to deep UV radiation. If the film is heated after exposure to light the photogenerated acid cleaves the p-t-butyloxycarbonyl ("t-BOC") group resulting in a thickness change in the regions exposed to radiation. Glass substrates coated with this formulation were exposed with an appropriate mask to deep CV light and the image developed by a post exposure bake of 2 minutes at 90°C. A magneto-optic trilayer consisting of 710 A Zr0₂/800 A TbFeCo/710 A Zr0₂ was deposited onto the polymer surface. The complete structure has sufficient track error signal level to be trackable on a precision optical disk test stand with the TES servo loop closed and has a CNR of 53 dB, comparable to the same MO composition deposited on injection molded grooved polycarbonate substrates.