Attachment of phosphonate-functionalised azo-dyes to oxide surfaces to give enhanced light and wet fastness

Mohapatra

Journal of the American Ceramic Society

et al. 2007

A hydroxyapatite/poly(ethylene-co-acrylic acid) (HAp/EAA) nanocomposite has been synthesized by a solution-based method. p-Aminophenyl phosphonic acid has been used as a coupling agent in order to enhance the bonding between HAp and EAA, and hence to improve the mechanical properties of the composite. XRD study has indicated the development of compressive and tensile stresses in a nanocomposite due to thermal expansion mismatch between nano-hydroxyapatite (n-HAp) and EAA. Fourier-transform infrared spectrometry (FTIR) and thermal analysis have shown the presence of strong interfacial bonding between n-HAp and EAA. The surface roughness and the homogeneous dispersion of nanoparticles have been observed by field emission scanning electron microscopy (FESEM). A comparison of mechanical properties between phosphonic acid treated (cn-HAp/EAA) and untreated (un-HAp/EAA) nanocomposites has been made. The use of a phosphonic acid coupling agent promotes the uniform dispersion of n-HAp in the polymer matrix with a strong nanoparticle-polymer interfacial bonding, which provides a means of preparing a HAp/polymer nanocomposite for implant applications. P. Brown-contributing editor

Section: Methodsmentioning

confidence: 99%

Processing and Properties of Nano‐Hydroxyapatite(n‐HAp)/Poly(Ethylene‐Co‐Acrylic Acid)(EAA) Composite Using a Phosphonic Acid Coupling Agent for Orthopedic Applications

Mohapatra

Journal of the American Ceramic Society

et al. 2007

“…The carboxylate group is usually used to connect molecules on oxide surfaces. The phosphonate one has been first involved in self-assembled monolayers (SAM) formation on metallic and metal oxide surfaces as protective films or for biomedical applications and recently in the grafting of bioactive molecules. , The phosphonate group has been recently shown to allow a higher grafting density of stilbene molecules at the surface of the nanoparticles than the carboxylate group . Here the effect of these two coupling agents, e.g., the surface chemistry, on the magnetite nanoparticle structure and the magnetic properties is investigated by 57 Fe in-field Mössbauer spectrometry, SQUID measurements, and IR spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Coupling Agent Effect on Magnetic Properties of Functionalized Magnetite-Based Nanoparticles

et al. 2008

The effect of surface inorganic-organic interactions on magnetic and structural properties of iron oxide magnetic nanoparticles functionalized by lipophilic stilbene molecules has been investigated. The molecules have been grafted through either phosphonate or carboxylate coupling agents. Mo ¨ssbauer spectra recorded at 300 and 77K suggest a global composition of Fe 2.82 O 4 for the two types of functionalization. Complementary in-field Mo ¨ssbauer and SQUID measurements have demonstrated that the nanoparticles consist in a magnetite core surrounded by an oxidized layer. The oxidized shell exhibits a spin canting in the carboxylate case leading to a decrease of the net magnetization of the oxide nanoparticle. No canting occurs in the phosphonate case, and the magnetic properties are therefore preserved. The magnetic properties thus depend on the coupling agent, e.g., surface interactions. This result is of primary importance to tune the magnetic properties of functionalized nanoparticles for biomedical and high density storage media applications.

“…19 NMR, in particular, offers the possibility of defining the orientation of the guest in the cavity 5,20-22 and of measuring formation constants for the dye-CD complex. 4 An analysis of the ROESY 1 H NMR spectra of 1 : 1 mixtures of a-cyclodextrin and 5 or 10 in D 2 O indicates that the four H-atoms ortho to the azo group form close contacts in the cavity with the cyclodextrin's H3 and H5 protons. Such an assembly with azo dyes can lead to protection from photobleaching.…”

Section: Resultsmentioning

confidence: 99%

“…To this end we have previously described a strategy for enhancing the wet fastness of dyes for inkjet printing based on incorporating ligating groups which form very stable complexes with the oxides used in photo quality papers. 4 In this paper we discuss adsorption a School of Chemistry, The University of Edinburgh, Joseph Black Building, Kings Buildings, West Mains Road, Edinburgh, UK EH9 3JJ. E-mail: p.a.tasker@ed.ac.uk; Fax: +44 131 6506453; Tel: +44 131 6504706 isotherm measurements on the uptake of simple dyes containing pendant sulfonic, carboxylic, phosphonic and arsonic acid groups (Fig.…”

Section: Introductionmentioning

confidence: 99%

The assembly of rotaxane-like dye/cyclodextrin/surface complexes on aluminium trihydroxide or goethite

et al. 2006

Self Cite

Simple azo-dyes carrying phosphonic acid and arsonic acid substituents such as 4-(4-hydroxyphenyl azo)phenylphosphonic acid (5) and 4-(4-hydroxyphenylazo)phenylarsonic acid (6) bind more strongly to high surface area oxides such as aluminium trihydroxide and goethite than their carboxylic and sulfonic acid analogues and the phosphonate-functionalized dyes have been shown to have greater humidity fastness when printed onto commercial alumina-coated papers. Adsorption isotherm measurements provide evidence for the formation of ternary dye/cyclodextrin/surface complexes. Dyes which form such ternary complexes show higher light fastness when printed onto alumina coated papers in an ink formulation containing alpha-cyclodextrin.