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Czaplewski C, Smalara K, Giełdoń A, Bobrowski M. Polymerization of chloro-p-xylylenes, quantum-chemical study. J Mol Model 2017; 23:40. [PMID: 28120123 PMCID: PMC5263197 DOI: 10.1007/s00894-016-3179-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 11/28/2016] [Indexed: 10/24/2022]
Abstract
The p-xylylene monomers of parylene N, C and D have similar high polymerization reactivity. For effective copolymerization processes this fact is basically a drawback and for instance the copolymerization with styrene doesn't go at all (Corley et al. J Pol Sc 13(68):137-156, [15]). Substitution of terminal hydrogen atoms by chlorine atoms reduces reactivity dramatically. 7,7,8,8-tetrachloro-p-xylylene and 2,5,7,7,8,8-hexachloro-p-xylylene can be isolated as yellow crystals. These crystals can be kept without any change in temperature below 0 ∘C, but they polymerize slowly at room temperature. Perchloro-p-xylylene is stable even at elevated temperatures and does not polymerize under any conditions. Both 7,7,8,8-tetrachloro-p-xylylene and 2,5,7,7,8,8-hexachloro-p-xylylene copolymerize with various vinyl monomers, such as styrene and others. In this work the polymerization reactions of different chloro-derivatives of p-xylylene were modeled by means of the DFT method with hybrid correlation functionals (B3LYP and PBE0) and, for comparison, by means of the Hartree Fock methods. We inquired both initiation as well as elongation polymeric reactions for each of the reactants. We survied their reactivity analytically examining energetics and configurations in Szwarc-like process. The quantitative influence of chlorine atoms on the reactivity in polymerization steps, their location in the reactants' structure (aromatic and/or aliphatic) as well as their number, were reviewed. The polymerizations of p-xylylenes with chlorine atoms as terminal aliphatic substituents yet revealed one more access path for parylenes' in situ functionalization.
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Affiliation(s)
- Cezary Czaplewski
- Department of Chemistry, University of Gdansk, Wita Stwosza 63, 80-308, Gdansk, Poland.,Department of Technical Physics and Applied Mathematics, Gdansk University of Technology, Narutowicza 11/12, 80-233, Gdansk, Poland
| | - Krzysztof Smalara
- Department of Chemistry, University of Gdansk, Wita Stwosza 63, 80-308, Gdansk, Poland.,Department of Technical Physics and Applied Mathematics, Gdansk University of Technology, Narutowicza 11/12, 80-233, Gdansk, Poland
| | - Artur Giełdoń
- Department of Chemistry, University of Gdansk, Wita Stwosza 63, 80-308, Gdansk, Poland.,Department of Technical Physics and Applied Mathematics, Gdansk University of Technology, Narutowicza 11/12, 80-233, Gdansk, Poland
| | - Maciej Bobrowski
- Department of Technical Physics and Applied Mathematics, Gdansk University of Technology, Narutowicza 11/12, 80-233, Gdansk, Poland.
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Karahan HE, Birer Ö, Karakuş K, Yıldırım C. Shadow-casted ultrathin surface coatings of titanium and titanium/silicon oxide sol particles via ultrasound-assisted deposition. ULTRASONICS SONOCHEMISTRY 2016; 31:481-489. [PMID: 26964975 DOI: 10.1016/j.ultsonch.2016.01.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 12/16/2015] [Accepted: 01/27/2016] [Indexed: 06/05/2023]
Abstract
Ultrasound-assisted deposition (USAD) of sol nanoparticles enables the formation of uniform and inherently stable thin films. However, the technique still suffers in coating hard substrates and the use of fast-reacting sol-gel precursors still remains challenging. Here, we report on the deposition of ultrathin titanium and titanium/silicon hybrid oxide coatings using hydroxylated silicon wafers as a model hard substrate. We use acetic acid as the catalyst which also suppresses the reactivity of titanium tetraisopropoxide while increasing the reactivity of tetraethyl orthosilicate through chemical modifications. Taking the advantage of this peculiar behavior, we successfully prepared titanium and titanium/silicon hybrid oxide coatings by USAD. Varying the amount of acetic acid in the reaction media, we managed to modulate thickness and surface roughness of the coatings in nanoscale. Field-emission scanning electron microscopy and atomic force microscopy studies showed the formation of conformal coatings having nanoroughness. Quantitative chemical state maps obtained by x-ray photoelectron spectroscopy (XPS) suggested the formation of ultrathin (<10nm) coatings and thickness measurements by rotating analyzer ellipsometry supported this observation. For the first time, XPS chemical maps revealed the transport effect of ultrasonic waves since coatings were directly cast on rectangular substrates as circular shadows of the horn with clear thickness gradient from the center to the edges. In addition to the progress made in coating hard substrates, employing fast-reacting precursors and achieving hybrid coatings; this report provides the first visual evidence on previously suggested "acceleration and smashing" mechanism as the main driving force of USAD.
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Affiliation(s)
- H Enis Karahan
- Materials Science and Engineering Graduate Program, Koç University, Sarıyer, Istanbul 34450, Turkey; Chemistry Department, Koç University, Sarıyer, Istanbul 34450, Turkey
| | - Özgür Birer
- Materials Science and Engineering Graduate Program, Koç University, Sarıyer, Istanbul 34450, Turkey; Chemistry Department, Koç University, Sarıyer, Istanbul 34450, Turkey; KUYTAM, Surface Science and Technology Research Center, Koç University, Sarıyer, Istanbul 34450, Turkey.
| | - Kerem Karakuş
- Materials Science and Engineering Graduate Program, Koç University, Sarıyer, Istanbul 34450, Turkey; Chemistry Department, Koç University, Sarıyer, Istanbul 34450, Turkey
| | - Cansu Yıldırım
- KUYTAM, Surface Science and Technology Research Center, Koç University, Sarıyer, Istanbul 34450, Turkey
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Paulus IE, Heiny M, Shastri VP, Greiner A. Chemical vapour deposition of soluble poly(p-xylylene) copolymers with tuneable properties. Polym Chem 2016. [DOI: 10.1039/c5py01343g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
High-molecular weight poly(p-xylylene) (PPX)/2-hydroxy-ethyl methacrylate (HEMA) copolymers are synthesized by chemical vapour deposition. The copolymer coatings are hydrophilic and show good cytocompatibility.
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Affiliation(s)
- Ilka E. Paulus
- Macromolecular Chemistry II University of Bayreuth and Bayreuth Center for Colloids and Interfaces
- Bayreuth
- Germany
| | - Markus Heiny
- Institute for Macromolecular Chemistry
- University of Freiburg
- Freiburg
- Germany
- BIOSS Centre for Biological Signalling Studies
| | - V. Prasad Shastri
- Institute for Macromolecular Chemistry
- University of Freiburg
- Freiburg
- Germany
- BIOSS Centre for Biological Signalling Studies
| | - Andreas Greiner
- Macromolecular Chemistry II University of Bayreuth and Bayreuth Center for Colloids and Interfaces
- Bayreuth
- Germany
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