Characterising a Custom-Built Radio Frequency PECVD Reactor to Vary the Mechanical Properties of TMDSO Films.

Plasma-polymerised tetramethyldisiloxane (TMDSO) films are frequently applied as coatings for their abrasion resistance and barrier properties. By manipulating the deposition parameters, the chemical structure and thus mechanical properties of the films can also be controlled. These mechanical properties make them attractive as energy adsorbing layers for a range of applications, including carbon fibre composites.

Quantifying Moisture Penetration in Encapsulated Devices by Heavy Water Mass Spectrometry: A Standard Moisture Leak Using Poly(ether-ether-ketone).

Moisture penetration into active biomedical implants such as the bionic ear and eye is a major problem in healthcare since surgery is required to replace devices affected by corrosion. Existing methods for measuring moisture leak rates such as the commercially available dynamic relative humidity method are not sufficiently sensitive to guarantee security against moisture penetration. Helium leak detection is highly sensitive but is challenged by the unknown relation to the moisture leak rate because of mixed flow modes involving liquid water.

Multitechnique investigation into the aqueous behavior of plasma polymers.

Plasma polymers are often used in applications requiring aqueous immersion; therefore, it is important to understand how this exposure affects the physical and chemical properties of the films. Three different plasma polymer films were deposited at different distances from the electrode, and the film properties were characterized using contact angle, ellipsometry, and x-ray photoelectron spectroscopy. The film behaviors in aqueous solutions were studied via quartz crystal microbalance with dissipation (QCM-D).

pH-dependent lipid vesicle interactions with plasma polymerized thin films.

Model lipid vesicle and supported lipid bilayer (SLB) systems are used in a variety of applications including biosensing, cell membrane mimics, and drug delivery. Exposure of a surface to a vesicle solution provides a straightforward method for creating such systems via vesicle adsorption and collapse. However, this process is complex and the relationship between the surface physicochemical properties and vesicle collapse is poorly understood.

Recent advances in porous silicon technology for drug delivery.

Porous silicon (pSi) is a nanostructured carrier system that has received considerable attention over the past 10 years, for use in a wide variety of biomedical applications, including biosensing, biomedical imaging, tissue scaffolds and drug delivery. This interest is due to several key features of pSi, including excellent in vivo biocompatibility, the ease of surface chemistry modification and the control over its 3D porous network structure. With control of these physical parameters pSi has successfully been used for the delivery of a variety of therapeutics, ranging from small-molecule drugs to larger peptide/protein-type therapeutics.

Influence of film stability and aging of plasma polymerized allylamine coated quartz particles on humic acid removal.

Plasma polymerized allylamine (ppAA) films have been successfully deposited on to the surface of quartz particles via a rotating barrel plasma reactor for humic acid removal. The films were deposited at a power of 25 W, allylamine flow rate of 4.4 sccm and polymerization times of 5 to 60 min.

Plasma polymerized allylamine coated quartz particles for humic acid removal.

Allylamine plasma polymerization has been used to modify the surface of quartz particles for humic acid removal via an inductively coupled rotating barrel plasma reactor. Plasma polymerized allylamine (ppAA) films were deposited at a power of 25 W, allylamine flow rate of 4.4 sccm and polymerization times of 5-60 min.

Surface chemistry of porous silicon and implications for drug encapsulation and delivery applications.

Porous silicon (pSi) has a number of unique properties that appoint it as a potential drug delivery vehicle; high loading capacity, controllable surface chemistry and structure, and controlled release properties. The native Si(y)SiH(x) terminated pSi surface is highly reactive and prone to spontaneous oxidation. Surface modification is used to stabilize the pSi surface but also to produce surfaces with desired drug delivery behavior, typically via oxidation, hydrosilylation or thermal carbonization.

Surface chemical modification to control molecular interactions with porous silicon.

Interactions between porous silicon (pSi) particles and probe molecules were evaluated to determine the effect of pSi and probe molecule chemistry on adsorption. Methylene blue, ethyl violet and orange G dyes were chosen for investigation as they possess distinct functionalities and charges. Several distinct pSi surface species were produced via thermal oxidation at 200-800 °C and their effect on adsorption investigated.

Thermal oxidation for controlling protein interactions with porous silicon.

Thermal oxidation of porous silicon (pSi) has been used to control interactions with three proteins; lysozyme, papain, and human serum albumin (HSA) enabling the influences of protein structure, molecular weight, and charge to be elucidated. Adsorption behavior was assessed via adsorption isotherms while the structures of adsorbed proteins were investigated using a bioactivity assay, FTIR, and zeta potential. Time-of-flight secondary ion mass spectrometry was used to examine protein pore penetration.

Aqueous and thermal oxidation of porous silicon microparticles: implications on molecular interactions.

Links between the mechanisms and kinetics of aqueous and dry thermal oxidation of porous silicon (pSi) microparticles have been investigated and the influence on molecular interaction established. zeta potential measurements have established the interplay between the dry oxidation state of pSi microparticles and their interfacial chemistry in aqueous solution, and Fourier transform infrared spectroscopy has demonstrated the effect of immersion time and oxidation temperature on surface chemistry. The influence of aqueous and thermal oxidation on molecular interactions and loading was investigated using methylene blue as a probe molecule.