ABSTRACTAlkylene‐ and arylene‐bridged cyclolinear polycarbosilanes (CLPCS) with 1,3‐disilacyclobutane (DSCB) rings incorporated in the main chain of the polymer were prepared by polycondensation between corresponding di‐functional DSCB derivatives and di‐Grignard reagents. Well‐defined, low molecular weight (Mn = 3–5K; DP = 17–26), hexylene‐ and phenylene‐bridged CLPCS polymers were obtained without appreciable ring opening of the DSCB rings. Large exothermic peaks were observed in the DSC for these CLPCSs, which indicated, along with the IR spectra, that crosslinking occurred on heating to about 250 °C via the ring opening of the embedded, alternating, DSCB rings. Moreover, PB‐CLPCS undergoes photochemically induced crosslinking on UV irradiation to form crosslinked polycarbosilane network films. The spin‐cast, cured, films of these CLPCSs exhibit relatively low dielectric constants and promising thermal and mechanical properties for applications in electronics, for example, directly UV‐photoimprinted low‐k dielectrics. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 1547–1557

ADVERTISEMENT RETURN TO ISSUEPREVEditorialNEXTRemembering Jim Crivello, former Editor, Chemistry of MaterialsLeonard V. InterranteCite this: Chem. Mater. 2015, 27, 7, 2244–2245Publication Date (Web):April 14, 2015Publication History Published online14 April 2015Published inissue 14 April 2015https://pubs.acs.org/doi/10.1021/acs.chemmater.5b01146https://doi.org/10.1021/acs.chemmater.5b01146editorialACS PublicationsCopyright © 2015 American Chemical Society. This publication is available under these Terms of Use. Request reuse permissions This publication is free to access through this site. Learn MoreArticle Views622Altmetric-Citations-LEARN 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 PDF (1 MB) Get e-AlertscloseSUBJECTS:Materials Get e-Alerts

ADVERTISEMENT RETURN TO ISSUEPREVEditorialNEXTCelebrating Twenty-Five Years of Chemistry of MaterialsLeonard V. Interrante and Edwin A. ChandrossCite this: Chem. Mater. 2014, 26, 1, 3–4Publication Date (Web):January 14, 2014Publication History Published online14 January 2014Published inissue 14 January 2014https://pubs.acs.org/doi/10.1021/cm4037988https://doi.org/10.1021/cm4037988editorialACS PublicationsCopyright © 2014 American Chemical Society. This publication is available under these Terms of Use. Request reuse permissions This publication is free to access through this site. Learn MoreArticle Views913Altmetric-Citations5LEARN 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 PDF (137 KB) Get e-AlertscloseSupporting Info (1)»Supporting Information Supporting Information SUBJECTS:Materials,Nanoparticles,Nanoporous materials,Porous materials,Thermoelectric materials Get e-Alerts

ADVERTISEMENT RETURN TO ISSUEEditorialNEXTA New Editor-in-Chief for Chemistry of MaterialsLeonard V. InterranteCite this: Chem. Mater. 2013, 25, 24, 4837–4838Publication Date (Web):December 23, 2013Publication History Published online23 December 2013Published inissue 23 December 2013https://pubs.acs.org/doi/10.1021/cm403441ghttps://doi.org/10.1021/cm403441geditorialACS PublicationsCopyright © 2013 American Chemical Society. This publication is available under these Terms of Use. Request reuse permissions This publication is free to access through this site. Learn MoreArticle Views613Altmetric-Citations-LEARN 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 PDF (127 KB) Get e-AlertscloseSUBJECTS:Biomaterials,Materials,Nanomaterials Get e-Alerts

We report cross-linked polycarbosilane (CLPCS) films with superior mechanical properties and insensitivity to moisture. CLPCS are prepared by spin-coating and thermal curing of hexylene-bridged disilacyclobutane (DSCB) rings. The resulting films are siloxane-free and hydrophobic, and present good thermal stability and a low dielectric constant of k = 2.5 without the presence of supermicropores and mesopores. The elastic stiffness and fracture resistance of the films substantially exceed those of traditional porous organosilicate glasses because of their unique molecular structure. Moreover, the films show a remarkable insensitivity to moisture attack, which cannot be achieved by traditional organosilicate glasses containing siloxane bonds. These advantages make the films promising candidates for replacing traditional organosilicate glasses currently used in numerous applications, and for use in emerging nanoscience and energy applications that need protection from moisture and harsh environments.

Solid solutions of SiC and AIN have been prepared by the co-pyrolysis of polysilanes and organoaluminum amides. In the presence of ammonia. Si3N4 and AIN are formed. These materials are fully characterized by TEM, SAD, SEM, XRPD, and elemental analyses. The influence of reaction conditions, as well as precursor properties and reactivity, on the composition and morphology of these materials is addressed.

Integrating low dielectric permittivity (low-k) polymers to metals is an exacting fundamental challenge because poor bonding between low-polarizability moieties and metals precludes good interfacial adhesion. Conventional adhesion-enhancing methods such as using intermediary layers are unsuitable for engineering polymer/metal interfaces for many applications because of the collateral increase in dielectric permittivity. Here, we demonstrate a completely new approach without surface treatments or intermediary layers to obtain an excellent interfacial fracture toughness of >13 J/m(2) in a model system comprising copper and a cross-linked polycarbosilane with k approximately 2.7 obtained by curing a cyclolinear polycarbosilane in air. Our results suggest that interfacial oxygen catalyzed molecular ring-opening and anchoring of the opened ring moieties of the polymer to copper is the main toughening mechanism. This novel approach of realizing adherent low-k polymer/metal structures without intermediary layers by activating metal-anchoring polymer moieties at the interface could be adapted for applications such as device wiring and packaging, and laminates and composites.

This article focuses on a relatively new group of organosilicon polymers known as cyclolinear polycarbosilanes (CLPCS). This group of polymers contains 1,3-disilacyclobutane (DSCB) rings, i.e., cyclo-{RSi(CH2)(2)SiR}-, bridged by various linking groups, so as to form linear chains with regularly spaced, strained, rings that function as latent sites for cross-linking. This ring-chain, or "beads-on-a-string", type polymer has the general formula, [-{RSi(CH2)(2)SiR}-Y-](n), where R and Y can be a variety of different groups, such as: R = -CH3, -C6H5 and -C6H4(CH3); Y = -(CH2)(x)-, -C6H4-(CH=CH)-C6H4-, and -C6H4-. Depending, in part, on the linking group, these CLPCS have been obtained by using two different synthesis methods, acyclic diene metathesis polymerization (ADMET) and Grignard coupling reactions. The resultant polymers exhibit a wide variation in physical properties, which depend on the nature of the silicon substituents, R, and the bridging group, Y. However, they also share some important characteristics, such as a relatively low glass transition temperature, amenability to the formation of thin films and coatings via spin-coating, and the tendency to undergo cross-linking on heating to 200-300 degrees C. The synthesis, characterization, and properties of these CLPCS are reviewed and their potential for application in such widely divergent areas as microelectronics processing (as low-k materials), protective, insulating coatings for Cu and other substrates, and photoluminescent films are described.

Differential scanning calorimetry studies of the reaction of a cyclolinear polycarbosilane [cyclo-(CH3Si(CH2)(2)SiCH3)-(CH2)(6)](n) on air exposed Cu surfaces reveal a substantial enhancement of the cross linking rate compared to noncatalytic surfaces, e.g., Au, Ag, Al, Si. The increased rate is attributed to surface Cu(II)-catalyzed opening of the embedded disilacyclobutane rings in the polymer This rate enhancement is used to selectively deposit a cross linked polycarbosilane on copper patterns in exclusion to the silicon substrate surface. These results could be attractive for realizing metal dielectric interfaces for applications in nanodevice wiring and packaging.

We demonstrate a novel strategy for toughening metal dielectric interfaces by catalyzed fissure of low-polarizability moieties in an organosilane monolayer. Photoelectron spectroscopy and ab initio calculations show that sevenfold toughening of Cu-silica interfaces is due to Cu-catalyzed disilacyclobutane ring opening and bonding. Our findings open up possibilities for directly integrating metals with molecularly derived low permittivity dielectrics for applications without using an intermediary glue layer, for example, by incorporating strained. moieties into polymer precursors.

AbstractThis report describes the results of a Project whose goals were to "assemble, collate and disseminate information about the scope of the newly-emerging discipline of materials chemistry, leading to an authoritative definition of the subject within the family of chemical sciences" and further, as a corollary, "to recommend to IUPAC how this new discipline might best be represented within the IUPAC structure". The history and current status of the research and teaching, only recently labeled as "materials chemistry", is described. This field has become one of the major growth sectors in pure and applied chemistry and now accounts for a significant fraction of all publications in the chemical sciences, based on measures such as journal citations and submitted papers and journals that are devoted entirely or in part to this subject. Nonetheless, there is still considerable confusion about what does, and does not, fall within the scope of "materials chemistry", and there is no consensus regarding a definition for the subject. After examining existing definitions for "chemistry" and "materials science" and considering prior attempts to define the subject, the following working definition for "materials chemistry" was suggested: "Materials chemistry comprises the application of chemistry to the design, synthesis, characterization, processing, understanding and utilisation of materials, particularly those with useful, or potentially useful, physical properties." In conclusion, the report suggests that IUPAC consider elevating this field from its current Subdivision status to that of "a cross-divisional Committee that would work with all the current IUPAC Divisions to develop and co-sponsor new projects, in the area of chemical education, nomenclature, terminology, health and safety, etc., that will increase the recognition of the current and future importance of this field to the international chemistry community".

Nucleophilic substitution reactions involving organomagnesium (Grignard) [1] and organolithium reagents have been used extensively for many years to form Si—C bonds (see Reaction Scheme 12.1). However, their use for the construction of hyperbranched polymers whose backbone contains, as a major structural component, silicon—carbon bonds, i.e., polycarbosilanes [2] is relatively more recent. (12.1) $$\begin{array}{l} {\rm{R}}_3 {\rm{SiX + MR'}} \to {\rm{R}}_3 {\rm{SiR' + MX}} \\ \left({{\rm{R,R' = alkyl}}\,{\rm{or aryl;}}\,{\rm{M = Mg(X),}}\,{\rm{Li,}}\,{\rm{Na}};{\rm{X = halogen, OR''}}} \right) \\ \end{array}$$ This chapter focuses on the application of such nucleophilic substitution reactions toward the synthesis of hyperbranched polycarbosilanes, with particular emphasis on those preparations that have resulted in relatively well characterized products. These syntheses are organized by the type of ABn monomer unit used (see Section 1.2), where A and B refer to the (C)X and (Si)Xn, respectively, functional ends of the monomer unit and where the nature of the coupling reaction leads to entirely or primarily Si—C bond formation. In most cases, these are "one-pot" reactions that employ monomers that bear halogen or alkoxy groups on the C and Si ends of the unit. Indeed, hyperbranched polycarbosilanes have been described, in general, as "obtained in one synthetic step via a random, one-pot polymerization of multifunctional monomers of AB n type" [2]. Treatment of the ABn monomer with either elemental Mg or an organolithium reagent, ideally (but not always) forms a complexed carbanion (the nucleophile) by reaction with the C–X end of the monomer unit, resulting in an intermediate of the type, (XxM)CSiXn, where M = Mg or Li, X = halogen or alkoxy, and x = 1 (Mg) or 0 (Li). Self-coupling of this reagent via reactions of the type shown in Reaction Scheme 12.1 leads to oligomeric and polymeric products that are connected primarily through Si—C bonds and yield an inorganic MXx by-product.

ADVERTISEMENT RETURN TO ISSUEEditorialNEXTChemistry of Materials Turns Twenty-OneLeonard V. InterranteCite this: Chem. Mater. 2009, 21, 1, 1–2Publication Date (Web):January 6, 2009Publication History Published online6 January 2009Published inissue 13 January 2009https://pubs.acs.org/doi/10.1021/cm803285bhttps://doi.org/10.1021/cm803285beditorialACS PublicationsCopyright © 2009 American Chemical Society. This publication is available under these Terms of Use. Request reuse permissions This publication is free to access through this site. Learn MoreArticle Views1719Altmetric-Citations1LEARN 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 PDF (47 KB) Get e-AlertscloseSUBJECTS:Materials,Materials science Get e-Alerts

The synthesis and study of it novel thermosetting, blue photoluminescent, cyclolinear polycarbosilane (CLPCS.) are reported. This cyclolinear polycarbosilane, in which disilacyclobutane (DSCB) rings alternate with trans-stilbene units (i.e., [-{cyclo-Si(CH3)(CH2)(2)Si(CH3) -C6H4-CH=CH-C6H4-](n), (S-CLPCS), was prepared by via acyclic diene metathesis (ADMET) polymerization. The polymer showed excellent solubility in common organic solvents and blue photoemission with a high emission quantum yield (Phi approximate to 0.65). Spin-coated polymer films were thermally or photochemically cross-linked to yield tough, insoluble films, which showed no significant decrease in photoluminescence intensity relative to that of the initial polymer Film prior to cross-linking. The effect of the DSCB spacers on the processability and optical properties of the polymers was investigated by preparing it series of alkylene-spaced polycarbosilane analogues and model compounds.