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Mesoporous silica supported adsorbents have been used towards metal ion removal from water due to their thermally stability and good sorption capacity. Thus, mesoporous silica-based methyl acrylate monomer (Silica-APTES-DPNO) was converted into hydroxamic acid (SBHA) by using oximation reaction and all products are analyzed by by FT-IR. The SBHA showed satisfactory binding properties with copper, cobalt, nickel and lead are 242, 206, 195 and 516 mg g−1, respectively, with the batch adsorption system was set to pH 6. The kinetics of metal ions binding obeyed the pseudo-1st-order process up to 60 min. In this study also consider the Langmuir and Freundlich isotherm to find out the sorption behavior. The isotherm study demonstrated the well fit with Freundlich isotherm (R 2 > 0.99). Thus, adsorption take place as a multilayer system, therefore, SBHA material is useful for the metal ions removal from water.

peer-reviewed, This work reported an improved approach to the synthesis of iron oxide nanostructures using iron(III) chloride as the precursor and hexamethylenetetramine (HMTA) as the key auxiliary. A range of iron oxide (alkoxide) nanostructures including nanosheets, hierarchical flowers (assembled by thin nanosheets), mesoporous hollow nanospheres and solid nanospheres were obtained only by altering the reaction temperature from 180 degrees C to 240 degrees C in a single synthetic protocol. Supplementary experiments driven by reaction time were designed in order to further clarify the morphological evolution behaviors of these nanostructures, which discovered that the spherical morphology with the size of about 150-200 nm formed from the inside of micro-scaled flower-like clusters gradually by the condensing and weaving of curled nanosheets, suggesting that the hollow nanospheres were obtained consequently by the further condensation of incompact nanospheres with the assistance of the rearrangement of surfactant micelles, followed by the oriented attachment assembly and Ostwald ripening., PUBLISHED, peer-reviewed

peer-reviewed, Epoxy resin (ER) thermosetting adhesives provide highly cross-linked 3-dimensional structures leading to highly stable and strong mechanical/physical performance in a wide range of bonding applications. However, such excellent physical attributes pose a significant challenge with respect to disassembly of the bonded adherends and previous disassembly methods have resulted in damage to the adherends. Hence, this paper presents a specifically engineered re-workable nanocomposite adhesive, created by embedding dielectric sensitive Fe3O4 hollow nanospheres (HNSs) in epoxy resin. This nanocomposite adhesive can be completely degraded by dielectric heating, resulting in facile disassembly of bonded adherends. FESEM and 3D Micro-CT characterisation demonstrates good dispersibility of the HNSs in cured ER, while the dielectric degradation performance and hardness/modulus were investigated by FESEM and nanoindentation. Results show that the Fe3O4 HNSs can effectively convert the microwave energy into thermal energy to significantly degrade the mechanical properties of the adhesive modulus and hardness by 83.4% and 90%, respectively. FESEM and HRTEM imaging attributes the reduction in nanocomposite adhesive properties to the formation of spatial voids nucleating from the embedded nanomaterials. Prior to dielectric heating, tensile loaded single lap-shear bonded joint tests indicated that the nanocomposite adhesive was 19.3% stronger than its neat ER adhesive counterpart due a nano-reinforcement toughening mechanism. However, after 3 minutes of dielectric heating exposure, the nanocomposite adhesive joint strength was reduced by 96.3% compared to just 18.7% for the neat ER adhesive, demonstrating the excellent re-workable performance of our new nanocomposite adhesive., PUBLISHED, peer-reviewed

Steady state luminescence and measurements of the luminescent lifetime as well as cyclic voltammetry have been used to elucidate the mechanism and dynamics of interaction between a luminescent ruthenium metal center and two different fractions of poly(2-methoxyaniline-5-sulfonic acid) (PMAS). The two fractions, high molecular weight (HMWT) PMAS and low molecular weight (LMWT) PMAS oligomer, showed significantly distinctive influences on the luminophore. The HMWT PMAS, confirmed to be an emeraldine salt by its characteristic redox chemistry, greatly impacted the diffusion coefficient of the Ru2+/3+ within the composite film, increasing the diffusion coefficient, DCT, by 2 orders of magnitude. The HMWT PMAS also resulted in quenching of the ruthenium-based emission. Significantly, these results indicate that quenching involves both static and dynamic processes, with the static quenching being the dominant process, suggesting that the metal center and polymer backbone were strongly associated. In stark contrast, the LMWT PMAS did not influence the electrochemical properties of the ruthenium metal center; however, it did double the emission observed from the ruthenium metal center. The insensitivity of the luminescence lifetime does suggest that, as with the HMWT PMAS, LWMT PMAS is strongly associated with the ruthenium metal center. The enhanced luminescence may allow for many potential sensor developments based on the luminescent ruthenium metal center, while the HMWT PMAS quenching could be utilized within quenching-based strategies or electrochemical devices.

Immobilisation of a luminescent material on an electrode surface is well known to substantially modulate its photophysical and electrochemical properties. Here a positively charged ruthenium metal complex ([Ru(bpy)3]2+) is immobilised on all electrode surface by ion paring with a sulfonated conducting polymer poly(2-methoxyaniline-5-sulfonic acid), (PMAS). Significantly, our study reveals that the electron transport between the ruthenium metal centres can be greatly enhanced due to the interaction with the conducting polymer when both are surface confined. Charge transfer diffusion rates in the present system are an order of magnitude faster than those found where the metal centre is immobilised within a non-conducting polymeric matrix. Electron transport appears to be mediated through the PMAS conjugated structure, contrasting with the electron hopping process typically observed in non-conducting metallopolymers. This increased regeneration rate causes the ruthenium-based electrochemiluminescence (ECL) efficiency to be increased. The impact of these observations on the ECL detection of low concentrations of disease biomarkers is discussed.

peer-reviewed, This thesis contributes to the development of novel synthesis protocols for polytypes and understanding of nanocrystal atomic structures in copper-based multi-elemental colloidal nanocrystals. The influence of ligands, precursors along with temperature as isolated factors in crystal phase and morphology is demonstrated. This allows a understanding of the intricate mechanisms behind the nucleation and sequential crystal growth. The thorough structural identification of sophisticated nanocrystal structures at an atomic level shines lights on elusive cationic ordering and disordering in multi-elemental colloidal nanocrystals and pushes the understanding of cationic precursor incorporation mechanisms beyond the current limitations. The synthesis of highly monodisperse CuZnSe2 (CZSe) colloidal nanocrystals is reported in Chapter 3. The crystal phase control of these nanocrystals with novel chemical compositions was achieved by controlling the presence or absence of phosphate-based ligands. Furthermore, the occurrence of polytypism between zinc blende and wurtzite was achieved by changing temperature and precursors. This understanding and control of crystal phase and polytypic occurrence in this system is of vital importance in applications such as thermoelectrics, photocatalysis and photovoltaics. Chapter 4 describes the dominating effects of precursor choice on the controlled occurrence of polytypism in the colloidal synthesis of CuαZnβSnγSeδ (CZTSe) nanocrystals. The synthesis of a linear polytype was simply triggered by the change of Sn precursor while the other metal, chalcogenide precursors along with temperature, solvents and surfactants remained the same. Three dimensional branched polytypic structures were synthesized at elevated temperature where in this case the choice of chalcogenides is the critical control factor. Chapter 5 fully deciphers the atomic structure in tetrapod CuαZnβSnγSeδ (CZTSe) nanocrystals with varied cationic compositions. This thorough stru

peer-reviewed, Oral consumption is the most commonly used method of small molecule drug delivery due to its simple administration, flexible formulation design, cost-effectiveness and established production technology. The typical pathway for an orally ingested drug involves dissolution in the gastrointestinal fluid, followed by permeation across the gut membrane and systemic circulation until it reaches the point of action. The rate of dissolution is therefore of critical importance to ensure high drug adsorption and maximum efficacy. The Biopharmaceutical Classification System (BCS) classified active pharmaceutical ingredients (APIs) into 4 categories based on their solubility and permeability among which BCS class II APIs are defined as being poorly soluble but highly permeable. The share of BCS class II APIs of newly developed drugs has increased from 30% to 60% in recent years. Therefore, it is critical for the industry to incorporate effective formulation approaches for improving solubility and dissolution rates of these APIs. In this regard, a number of approaches have been investigated. Amorphous solid dispersion (ASD) is a successful approach for transforming and stabilizing crystalline drugs to amorphous form with higher solubility/dissolution rates. Spray drying (SD) is a solvent-based drying method that has been used for formulating ASDs with improved solubility and stability. Biopharmaceuticals are pharmaceuticals that are inherently biological in nature and manufactured using biotechnology. This broad definition includes any type of blood product, vaccines, antibodies, proteins and nucleic acids. Protein-based pharmaceuticals are among the fastest growing categories of therapeutic agents. Therefore, the development of stable protein based formulations with controlled physicochemical properties is of high interest. Reversible and irreversible aggregation in liquid protein formulations specifically at high concentrations is a challenging problem for biopharmaceutical pr

peer-reviewed, Oral consumption is the most commonly used method of small molecule drug delivery due to its simple administration, flexible formulation design, cost-effectiveness and established production technology. The typical pathway for an orally ingested drug involves dissolution in the gastrointestinal fluid, followed by permeation across the gut membrane and systemic circulation until it reaches the point of action. The rate of dissolution is therefore of critical importance to ensure high drug adsorption and maximum efficacy. The Biopharmaceutical Classification System (BCS) classified active pharmaceutical ingredients (APIs) into 4 categories based on their solubility and permeability among which BCS class II APIs are defined as being poorly soluble but highly permeable. The share of BCS class II APIs of newly developed drugs has increased from 30% to 60% in recent years. Therefore, it is critical for the industry to incorporate effective formulation approaches for improving solubility and dissolution rates of these APIs. In this regard, a number of approaches have been investigated. Amorphous solid dispersion (ASD) is a successful approach for transforming and stabilizing crystalline drugs to amorphous form with higher solubility/dissolution rates. Spray drying (SD) is a solvent-based drying method that has been used for formulating ASDs with improved solubility and stability. Biopharmaceuticals are pharmaceuticals that are inherently biological in nature and manufactured using biotechnology. This broad definition includes any type of blood product, vaccines, antibodies, proteins and nucleic acids. Protein-based pharmaceuticals are among the fastest growing categories of therapeutic agents. Therefore, the development of stable protein based formulations with controlled physicochemical properties is of high interest. Reversible and irreversible aggregation in liquid protein formulations specifically at high concentrations is a challenging problem for biopharmaceutical pr

peer-reviewed, The development of “smart” biomaterials for biomedical applications such as drug delivery systems, tissue engineering applications and neural prosthetics is a goal sought after by many researchers. Multifunctional and electroactive hydrogels as a class, possess inherent properties that can bring these goals to fruition. However, their practical applications are limited by the difficulties associated in synthesising hydrogels with properties which can be readily tuned and incorporating electroactive components into hydrogels without compromising the electrochemical properties of the overall structure. This work describes the synthesis and characterisation of hydrogels with easily tuneable mechanical and swelling properties, and the synthesis and characterisation of a novel electroactive hydrogel for potential applications in tissue engineering, drug delivery, and neural coatings respectively. An acrylate based copolymer, poly(acrylic acid)-cysteine-acrylic acid (PCA) was prepared and cross-linked via photo initiated thiol-acrylate chemistry. By using this Michael type addition chemistry, it was possible to synthesize a range of hydrogels and tune the mechanical and swelling properties of the formed hydrogels. The resulting hydrogels thus possessed mechanical and swelling properties which could be readily tuned by adjusting the ratio of thiol to acrylate concentration and changing the cross-linking time. Biocompatibility studies showed that the hydrogels exhibited excellent biocompatibility when tested against RPE1 cell line, and were observed to facilitate cell adhesion and proliferation without the need for further modification of the hydrogel with ECM proteins. These PCA hydrogels were used to further investigate the electrodeposition of electroactive polymers within hydrogels, and used to develop an electroactive hydrogel by electrochemically depositing PEDOT within the matrix of the hydrogels. In investigating the electrodeposition of electroactive polymers in hy

peer-reviewed, The development of “smart” biomaterials for biomedical applications such as drug delivery systems, tissue engineering applications and neural prosthetics is a goal sought after by many researchers. Multifunctional and electroactive hydrogels as a class, possess inherent properties that can bring these goals to fruition. However, their practical applications are limited by the difficulties associated in synthesising hydrogels with properties which can be readily tuned and incorporating electroactive components into hydrogels without compromising the electrochemical properties of the overall structure. This work describes the synthesis and characterisation of hydrogels with easily tuneable mechanical and swelling properties, and the synthesis and characterisation of a novel electroactive hydrogel for potential applications in tissue engineering, drug delivery, and neural coatings respectively. An acrylate based copolymer, poly(acrylic acid)-cysteine-acrylic acid (PCA) was prepared and cross-linked via photo initiated thiol-acrylate chemistry. By using this Michael type addition chemistry, it was possible to synthesize a range of hydrogels and tune the mechanical and swelling properties of the formed hydrogels. The resulting hydrogels thus possessed mechanical and swelling properties which could be readily tuned by adjusting the ratio of thiol to acrylate concentration and changing the cross-linking time. Biocompatibility studies showed that the hydrogels exhibited excellent biocompatibility when tested against RPE1 cell line, and were observed to facilitate cell adhesion and proliferation without the need for further modification of the hydrogel with ECM proteins. These PCA hydrogels were used to further investigate the electrodeposition of electroactive polymers within hydrogels, and used to develop an electroactive hydrogel by electrochemically depositing PEDOT within the matrix of the hydrogels. In investigating the electrodeposition of electroactive polymers in hy

peer-reviewed, The development of “smart” biomaterials for biomedical applications such as drug delivery systems, tissue engineering applications and neural prosthetics is a goal sought after by many researchers. Multifunctional and electroactive hydrogels as a class, possess inherent properties that can bring these goals to fruition. However, their practical applications are limited by the difficulties associated in synthesising hydrogels with properties which can be readily tuned and incorporating electroactive components into hydrogels without compromising the electrochemical properties of the overall structure. This work describes the synthesis and characterisation of hydrogels with easily tuneable mechanical and swelling properties, and the synthesis and characterisation of a novel electroactive hydrogel for potential applications in tissue engineering, drug delivery, and neural coatings respectively. An acrylate based copolymer, poly(acrylic acid)-cysteine-acrylic acid (PCA) was prepared and cross-linked via photo initiated thiol-acrylate chemistry. By using this Michael type addition chemistry, it was possible to synthesize a range of hydrogels and tune the mechanical and swelling properties of the formed hydrogels. The resulting hydrogels thus possessed mechanical and swelling properties which could be readily tuned by adjusting the ratio of thiol to acrylate concentration and changing the cross-linking time. Biocompatibility studies showed that the hydrogels exhibited excellent biocompatibility when tested against RPE1 cell line, and were observed to facilitate cell adhesion and proliferation without the need for further modification of the hydrogel with ECM proteins. These PCA hydrogels were used to further investigate the electrodeposition of electroactive polymers within hydrogels, and used to develop an electroactive hydrogel by electrochemically depositing PEDOT within the matrix of the hydrogels. In investigating the electrodeposition of electroactive polymers in hy

peer-reviewed, Oral consumption is the most commonly used method of small molecule drug delivery due to its simple administration, flexible formulation design, cost-effectiveness and established production technology. The typical pathway for an orally ingested drug involves dissolution in the gastrointestinal fluid, followed by permeation across the gut membrane and systemic circulation until it reaches the point of action. The rate of dissolution is therefore of critical importance to ensure high drug adsorption and maximum efficacy. The Biopharmaceutical Classification System (BCS) classified active pharmaceutical ingredients (APIs) into 4 categories based on their solubility and permeability among which BCS class II APIs are defined as being poorly soluble but highly permeable. The share of BCS class II APIs of newly developed drugs has increased from 30% to 60% in recent years. Therefore, it is critical for the industry to incorporate effective formulation approaches for improving solubility and dissolution rates of these APIs. In this regard, a number of approaches have been investigated. Amorphous solid dispersion (ASD) is a successful approach for transforming and stabilizing crystalline drugs to amorphous form with higher solubility/dissolution rates. Spray drying (SD) is a solvent-based drying method that has been used for formulating ASDs with improved solubility and stability. Biopharmaceuticals are pharmaceuticals that are inherently biological in nature and manufactured using biotechnology. This broad definition includes any type of blood product, vaccines, antibodies, proteins and nucleic acids. Protein-based pharmaceuticals are among the fastest growing categories of therapeutic agents. Therefore, the development of stable protein based formulations with controlled physicochemical properties is of high interest. Reversible and irreversible aggregation in liquid protein formulations specifically at high concentrations is a challenging problem for biopharmaceutical pr

peer-reviewed, This work describes a novel approach to produce high quality release paper at lower cost than traditional methods. The anti-adhesive properties of release paper require the use of expensive machine glazed kraft or “Glassine” paper as the paper base. A series of polymer coatings including polyvinyl alcohol, carboxymethyl cellulose, polyethylene vinyl acetate, and polystyrene were chemically synthesized and coated onto a low cost pulp paper base. Surface roughness (Sa) and smoothness coefficients (k) were determined by atomic force micros copy (AFM), and the interactions between the polymer coating and base paper were investigated by Raman spectroscopy. Studies show the use of polyethylene vinyl acetate (PEVA) as a pre-coating layer on low cost pulp paper exhibits similar anti-adhesive properties as higher cost paper bases. In low margin markets such as the production of release paper, decreases in cost are critical to industry survival.

peer-reviewed, This work describes a novel approach to produce high quality release paper at lower cost than traditional methods. The anti-adhesive properties of release paper require the use of expensive machine glazed kraft or “Glassine” paper as the paper base. A series of polymer coatings including polyvinyl alcohol, carboxymethyl cellulose, polyethylene vinyl acetate, and polystyrene were chemically synthesized and coated onto a low cost pulp paper base. Surface roughness (Sa) and smoothness coefficients (k) were determined by atomic force micros copy (AFM), and the interactions between the polymer coating and base paper were investigated by Raman spectroscopy. Studies show the use of polyethylene vinyl acetate (PEVA) as a pre-coating layer on low cost pulp paper exhibits similar anti-adhesive properties as higher cost paper bases. In low margin markets such as the production of release paper, decreases in cost are critical to industry survival.

peer-reviewed, In this work, lignin was spray dried with sodium lauryl sulphate (SLS) in order to improve the compaction properties of lignin. Bulk level and physicochemical properties of spray dried formulations were measured and compared to as-received lignin and lactose which was used as a reference excipient. Single component tablets from individual powders were prepared and the mechanical properties of these powders were investigated by analysing force–displacement curves recorded during tableting, using a series of compaction equations. Moreover, the performance of these excipients in binary blends containing an active pharmaceutical ingredient (API) was investigated. A positive effect of SLS on the mechanical properties and bulk level properties of the spray dried formulations was observed. Spray dried formulations containing SLS showed superior flow properties to pure spray dried lignin while retaining similar particle size distributions. Spray dried formulations containing up to 10 w/w% SLS also showed superior compactibility in binary blends to as-received materials at porosity levels relevant for immediate release tablets. This study highlights the importance of understanding the compaction mechanics of single component powders as a means of predicting their behaviour in multi-component blends.

peer-reviewed, The development of biocompatible membrane materials capable of delivering active pharmaceutical ingredients (APIs) over a fixed time period offers significant advantages to the pharmaceutical and biomedical industries alike. In addition the incorporation of APIs within polymeric materials potentially allows for the formation of amorphous solid dispersions (ASDs), which have shown enhanced bioavailability, increased dissolution profiles and enhanced adsorption into the blood stream. Mixed matrix membranes (MMMs) have been at the forefront of such developments, however manufacturing MMMs with consistent batch to batch physical characteristics has proved challenging thereby significantly impeding the use of such materials by the pharmaceutical sector. This article describes the development, for the first time, of API and molecular sieve loaded mixed matrix membranes (MMMs) via electro spinning techniques. The developed membranes displayed consistent and controllable physical properties and more efficient API release relative to membranes prepared using traditional casting techniques. Mathematical modelling disclosed that the membranes generated via electrospinning show excellent correlation between experimental and predicted API release kinetics thereby paving the way for the development of MMMs for both pharmaceutical and biomedical applications.

peer-reviewed, The electrochemiluminescent (ECL) performance of three ruthenium-based metallopolymer platforms with different homogeneous charge transfer diffusion coefficients (DCT) is reported. Significantly, simultaneous detection of light and current in tandem with steady-state photoluminescence studies demonstrate that increasing the rate of Ru3 + production via enhanced charge transport results in a decrease in ECL intensity of up to 82% when the concentration of the co-reactant, sodium oxalate, is low, i.e., sub-mM. Spectroelectrochemical studies demonstrate that for maximum sensitivity to be obtained, the electroactive properties of the polymeric support matrix need to be considered in tandem with luminophore, analyte and co-reactant concentrations.