English

Near-IR reflectance spectroscopy has been used to study the curing of ethyl cyanoacrylate adhesive on polished dental glass and microscope slide substrates. The effects of changing the glue film thickness and the type of substrate on the curing rate have been investigated whilst maintaining a constant humidity. The FTIR spectral data has been used to calculate and plot the extents of cure versus time for various film thicknesses.

Glass ionomer cement (GIC) has been successfully used in dental field for more than 40 years. Despite numerous advantages of GIC, low bond strength and slow setting rate limited conventional GICs for use only at low stress-bearing areas. To improve bond strength to tooth, two kinds of cyanoacrylates such as ethyl 2-cyanoacrylate (EC) and allyl 2-cyanoacrylate (AC) were added in a commercial GIC. Changes in setting time of cyanoacrylate-modified GICs (CMGICs) according to the concentration of cyanoacrylates and/or p-toluene sulfonic acid (TSA) was investigated using a rheometer.

Polymer electronics plays more and more important role nowadays, especially in flexible electronics. The progress is also reflected in packaging materials and technologies. Metallic solders are replaced by electrically conductive adhesives based on polymer’s matrix. Very high volume production also requires new methods of adhesive deposition. The ink-jet printing technology seems to be very promising for bumps making in Flip- Chip type interconnections. Unfortunately, the technology is only in its infancy.

The present work demonstrates feasibility of an inkjettable, isotropically electrically conductive adhesive in the form of a silver loaded resin with a 2-step curing mechanism. In the first step, the adhesive is dispensed (jetted) and precured leaving a “dry” surface. The second step consists of assembly and final curing. The 2-step cure system is based on a Acrylate-Epoxy-Resin matrix with very low viscosity, i.e., 3 mPas of newtonian properties. Spheroidal silver particles of high purity and a compatible organic coating have been loaded at 70% by weight.

Many advanced medical and biological devices require microscale patterning of cells, proteins, and other biological materials. This article describes the use of piezoelectric ink jet processing in the fabrication of biosensors, cell-based assays, and other microscale medical devices. A microelectromechanical system-based piezoelectric transducer was used to develop uniform fluid flow through nozzles and to prepare well-defined microscale patterns of proteins, monofunctional acrylate ester, sinapinic acid, deoxyribonucleic acid (DNA), and DNA scaffolds on relevant substrates.

A photometric assay was developed to study the surface erosion of polymeric nanoparticles. The hydrolytic degradation of polyalkylcyanoacrylate particles was studied in different environments (NaOH, buffer, cell culture medium and serum). The influence of particle modification on the degradation rate was assessed. Particularly, the effect of polymer coating for particle targeting and fluorescence labelling was investigated. From the absorption data, a t 50% and t 100% can be calculated for fast degrading particles and obtained by an extrapolation in case of a slow degradation process.

Synthetic adhesives have largely displaced natural adhesives in the automotive, aerospace, biomedical, electronic, and marine equipment industries over the past century. We have demonstrated the thin film deposition of biological adhesives using piezoelectric inkjet technology. A MEMS based piezoelectric actuator was controlled to jet uniform fluid flow of the adhesive solution through the ink jet nozzles. Microscopic deposition of adhesives enables improved bonding for a range of advanced electronic and biomedical applications.

In this study, we have demonstrated the use of piezoelectric inkjet printing to fabricate microscale patterns of Vetbond® n-butyl cyanoacrylate tissue adhesive. Optical microscopy, atomic force microscopy, nanoindentation, and a cell viability assay were used to examine the structural, mechanical, and biological properties of microscale cyanoacrylate patterns. The ability to rapidly fabricate microscale patterns of medical and veterinary adhesives will enable reduced bond lines between tissues, improved tissue integrity, and reduced toxicity.

Exploiting crystal engineering and supramolecular synthon concepts, a series of new gelator salts based on primary ammonium dicarboxylate (PAD) salts of azobenzene-4,4′-dicarboxylic acid and primary alkyl amines have been synthesized and characterized by various physico-chemical techniques. Most of the salts were shown to form gels with various solvents. Interestingly, most of the gelator salts possessed rarely observed reverse-thermal gelation (gelation with the rise of temperature) ability of aromatic solvents which may be relevant in developing thermo-responsive materials.

An adhesive cement is prepared by coating an aluminosilicate glass ionomer with an acid polymerization inhibitor of pKa between 2-3.5, and then mixing the treated glass with cyanoacrylate monomer and water. The glass is treated by dissolving the acid, typically tartaric, tartronic, malic, maleic or mellitic acid in methanol and adding the glass powder to form a slurry, then evaporating the methanol.