Search results for "Mono"
showing 10 items of 6843 documents
Polymerization of mono- and multilayer forming diacetylenes
1977
Heptadeca-2,4-diine-1-ol and Heptadeca-2,4-diine-1-acid were synthesized and their polymerization behaviour in the solid state was investigated. Both compounds polymerize thermally below the melting point and photochemically under the action of uv-light to form polymers via 1,4-addition to the conjugated triple bonds with a backbone of conjugated double-and triple-bonds. The photoresponse spectra resemble the absorption spectra exhibiting maxima of photoreactivity in the absorption band of the conjugated triple bonds of the monomers.
Photoreactive Langmuir–Blodgett–Kuhn multilayer assemblies from functionalized liquid-crystalline side chain polymers, I. Homopolymers containing azo…
1991
Stable monomolecular layers of a liquid-crystalline homopolymer bearing azobenzene chromophores in the mesogenic side groups could be prepared at the water–air interface by slow compression at room temperature. From the area per monomer unit of A0≈0.25 nm2 a structural model with tightly packed azobenzene groups oriented nearly parallel to the surface normal was deduced. After transfer to a solid support in a Y-type mode the obtained Langmuir–Blodgett–Kuhn (LBK) multilayer assemblies of varying thicknesses (from a double layer to a thick film of d = 238 nm, capable of guiding optical modes) were prepared and analyzed by X-ray reflection and optical evanescent wave techniques. A monolayer th…
Discotic liquid crystals at the air water interface
1991
The monolayer properties of two types of discotic liquid crystals, hexasubstituted triphenylenes 1 and azo derivatives of phloroglucinol 5, were examined. First investigations show that these discotic liquid crystals form stable monolayers. It could be shown that electron acceptors insert into the monolayer of 1. Azo discs display a packing behaviour at the monolayer that is ascribed to a side-on packing of the molecules.
Synthesis of Processable Inorganic‐Organic Hybrid Polymers Based on Poly(silsesquioxanes): Grafting from Polymerization Using ATRP
2008
Inorganic-organic hybrid polymers have been synthesized utilizing atom transfer radical polymerization (ATRP) from a functionalized poly(methylsilsesquioxane) (PMSSQ) macroinitiator. Different polymeric ATRP initiators were prepared by co-condensation of functionalized trichlorosilanes with methyltrimethoxysilane. Various vinyl monomers have been successfully grafted from these macroinitiators, demonstrating a highly variable synthetic concept, which offers the chance to synthesize a wide spectrum of inorganic-organic hybrid polymers. All synthesized polymers were soluble in various organic solvents. Spin-coating these hybrid materials onto various substrates could produce stable and adhere…
One-Step Block Copolymer Synthesis versus Sequential Monomer Addition: A Fundamental Study Reveals That One Methyl Group Makes a Difference
2018
Block copolymers of polyisoprene and polystyrene are key materials for polymer nanostructures as well as for several commercially established thermoplastic elastomers. In a combined experimental and kinetic Monte Carlo simulation study, the direct (i.e., statistical) living anionic copolymerization of a mixture of isoprene (I) and 4-methylstyrene (4MS) in nonpolar media was investigated on a fundamental level. In situ 1H NMR spectroscopy enabled to directly monitor gradient formation during the copolymerization and to determine the nature of the gradient. In addition, a precise comparison with the established copolymerization of isoprene and styrene (I/S) was possible. Statistical copolymer…
Impact of Amino-Functionalization on the Response of Poly(ethylene glycol) (PEG) to External Stimuli
2022
It is shown that amino-functionalization of poly(ethylene glycol) (PEG) with the comonomer N,N-diethyl glycidyl amine (DEGA) triggers the emergence of extraordinary stimuli responsiveness and phase behavior of PEG. In dependence of the solution pH, tapered PEG-co-PDEGA exhibits a highly cooperative two-step inverse phase transition with respect to temperature. The polymer forms dispersed metastable nanoglobules in the medically relevant temperature range around human body temperature. Independently, cloud points can be adjusted between 40 and 90 °C via the pH of the solution. Changing the polymer architecture to a block structure, in pronounced contrast, the polymer exhibits a gradual growt…
Polymeric amphiphiles with hydrophilic main chain spacers: Studies in monolayers and Langmuir-Blodgett multilayers
1988
A methacrylic lipid was polymerized to form an amphiphilic homopolymer and random copolymers with various levels of acrylic acid comonomers. The behavior of these polymeric lipids was investigated in monolayers at the air-water interface and in Langmuir-Blodgett multilayers on polymer foil supports. The acrylic acid acts as a hydrophilic spacer along the polymer backbone, and improves the ability of the polymer to self-organize into highly ordered monolayers and ultimately LB multilayers. It is shown that the quality and stability of the multilayers increase substantially with the increase in comonomer content.
Cyclodextrins in polymer synthesis: free radical polymerization of cyclodextrin complexes with oxazoline-functionalized vinyl monomers as guest molec…
2000
The synthesis of five new oxazoline functionalized vinyl monomers N-[4-(4′,5′-dihydrooxazol-2-yl)phenyl]acrylamide (3 a), N-[4-(4′,5′-dihydrooxazol-2-yl)phenyl]-2-methylacrylamide (3 b), N-{10-[4-(4′,5′-dihydrooxazol-2-yl)phenylcarbamoyl]decyl}-2-acrylamide (5 a), N-{10-[4-(4′,5′-dihydrooxazol-2-yl)phenylcarbamoyl]decyl}-2-methylacrylamide (5 b) and N-[4-(4′,5′-dihydrooxazol-2-yl)-phenyl]-4-vinylbenzamide (7) is described. With an equimolar amount of 2,6-dimethyl-β-cyclodextrin (DMCD) these monomers formed hydrophilic inclusion complexes 3 a,b-DMCD, 5 a,b-DMCD and 7-DMCD. These complexes were polymerized radically in an aqueous medium. Resulting polymers P-(3 a, b), P-(5 a, b) and P-(7) pre…
Functional Group Distribution and Gradient Structure Resulting from the Living Anionic Copolymerization of Styrene and para-But-3-enyl Styrene
2014
The functional group distribution along the polymer backbone resulting from the living anionic copolymerization of styrene (S) and para-but-3-enyl styrene (pBuS) was investigated in cyclohexane at room temperature. A variety of copolymers with different comonomer contents x(S) = 0–0.84 have been synthesized with molecular weight dispersities Mw/Mn ≤1.12. All polymers have been characterized in detail by 1H NMR spectroscopy, size exclusion chromatography (SEC), and differential scanning calorimetry (DSC). A detailed understanding of the monomer sequence distribution during the copolymerization was achieved by real-time 1H NMR spectroscopy. This technique permits us to determine the changing …
Some monomers, oligomers and polymers with conjugated triple bonds
1991
In the first part new monoaminodiacetylenes with different numbers of CH2-groups, the formation of Perowskit-type Mn complexes and their polymerizability are described. Symmetrical diaminodiacetylenes and some derivatives therefrom have also been prepared. The second part deals with different types of polymers with diacetylene units in the backbone. Under irradiation color formation and crosslinking take place. Well-defined low molecular weight model compounds of polydiacetylenes is the subject of the third part. Finally rod-like but soluble polymers with alternating p-phenylene and acetylene units are described.