Chemistry

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Arborescent Core–Shell–Corona Copolymers by Self-Assembly as Templates for the Preparation of Metallic Nanoparticles
(University of Waterloo, 2020-11-19) Worku, Aklilu; Gauthier, Mario
The preparation of metallic nanoparticles has been a rapidly growing field of research in recent years, because of the unique physical properties and applications of these materials. The development of applications for nanomaterials and nanostructures generally requires control over their size, size distribution, morphology, and chemical composition. Different methods have been developed to that end. Arborescent copolymers, a unique type of graft copolymers with a dendritic architecture, were previously investigated as templates for the preparation of metallic nanoparticles. Specifically, polystyrene-graft-[poly(2-vinylpyridine)-block-polystyrene] copolymers were obtained by successive functionalization and anionic grafting reactions leading to a covalently bonded, layered structure with a core of arborescent polystyrene, an inner shell of poly(2-vinyl pyridine) (P2VP), and a corona of polystyrene chains. While these materials were shown to be useful as template, due to their inherent stability, their synthesis was limited by very low grafting yields in most cases. In this Thesis a new method is demonstrated for the preparation of arborescent core–shell–corona structures called arborescent copolymer complexes (ACC), namely polystyrene-graft-poly(2-vinylpyridine)-graft-poly(acrylic acid)-block-polystyrene, obtained by the self-assembly of arborescent polystyrene-graft-poly(2-vinylpyridine) copolymers with poly(acrylic acid)-block-polystyrene copolymers via weak acid–weak base interactions. It involves anionic grafting for the synthesis of the arborescent polystyrene-graft-poly(2-vinyl pyridine) substrates, atom transfer radical polymerization (ATRP) to synthesize the poly(acrylic acid)-block-polystyrene copolymers, and mixing the two components in solution in appropriate ratios to prepare the polymeric templates in high yield. This is a new, simpler approach to the synthesis of core–shell–corona (CSC) structures comparable to those obtained by tedious anionic grafting procedures using “living” block copolymers. The complexation reaction was investigated using dynamic light scattering (DLS), transmission electron microscopy (TEM) and atomic force microscopy (AFM) analysis. In most cases, an increase in size was observed after a substrate was complexed with a block copolymer to yield self-assembled structures with a single, narrow size population. The DLS data, together with the non-aggregated particles of uniform size observed in the AFM and TEM images, provided strong evidence for the formation of the desired CSC complexes. Different generations (G2–G4) of ACCs were successfully loaded with tetrachloroauric acid (HAuCl¬4), and intramolecular phase separation was especially apparent for higher generation (G3 and G4) templates, producing a variety of morphologies including spherical, ring-like, raspberry, and core–shell metal distributions. Subsequent reduction with sodium borohydride (NaBH4) yielded aggregation-free gold nanoparticles with a size ranging from 4 to 17 nm inside the polyion complexes. Overall, the results obtained in the current investigation clearly show that ACCs, obtained in high yield by a simple self-assembly procedure using arborescent polystyrene-graft-poly(2-vinylpyridine) and poly(acrylic acid)-block-polystyrene copolymers, have great potential as templates for the preparation of metallic nanoparticles. The nanomorphologies obtained with the ACCs are comparable to those observed for arborescent polystyrene-graft-poly(2-vinylpyridine)-block-polystyrene systems in many cases. Not only the simplicity of the self-assembly approach, but also the versatility of the process enables the synthesis of a wide range of these interesting materials on a larger (multi-gram) scale, which will facilitate the investigation of their properties in relation to applications in different areas such as sensors and catalysts.
Arborescent Polypeptides for Sustained Drug Delivery Applications
(University of Waterloo, 2017-08-09) Alsehli, Mosa; Gauthier, Mario
This Ph.D. dissertation describes the synthesis of arborescent copolymers of generations G1 and G2 designed to serve as drug delivery nanocarriers for cancer treatment. Poly(γ-benzyl L-glutamate) (PBG) building blocks were generated by ring-opening polymerization of γ-benzyl L-glutamic acid N-carboxyanhydride (Glu-NCA) initiated with n-hexylamine. Partial or full deprotection of the benzyl ester groups followed by coupling with PBG chains yielded a comb-branched (arborescent polymer generation zero or G0) PBG structure. Additional cycles of deprotection and grafting yielded G1 and G2 arborescent polypeptides. Optimization of the arborescent PBG synthesis was carried out in terms of the reaction temperature, solvent composition, reaction time, and mole ratio of reactants and coupling agents. Side chains of poly(ethylene oxide) (PEO) were then grafted either randomly or at the chain ends of the arborescent PBG substrates to produce amphiphilic arborescent copolymers denoted as PBG-g-PEO and PBG-eg-PEO, respectively. The branching density of the G0PBG substrates was controlled by varying the length and the deprotection level of the linear PBG substrates used in their synthesis. Three G0PBG cores with branching densities varying from a compact and dense to a loose and porous structure were thus synthesized. The arborescent PBG-g-PEO amphiphilic copolymers formed mostly unimolecular micelles with small amounts of aggregation in aqueous media, whereas arborescent PBG-eg-PEO were completely devoid of aggregation. The hydrodynamic diameter of the copolymers varied from 13 to 39 nm, depending on their generation number and the branching density of the G0PBG cores. The ability of these unimolecular micelles to encapsulate and release doxorubicin (DOX), an anticancer drug, was correlated with their generation number and the branching density of the hydrophobic cores. Both the drug loading content (DLC) and the drug loading efficiency (DLE) increased with the generation number of the copolymers as a result of increasing the PBG content in the micelles. For each generation, slightly higher values of DLE and DLC were observed for micelles with a denser core structure. The release profiles indicated that the drug release rate could be modulated by the generation number of the copolymers or by controlling the branching density, and thereby the porosity of the cores: Micelles with more densely branched cores decreased the diffusion rate of the drug. Three different strategies were examined to load DOX into G1PBG-eg-PEO and G2PBG-eg-PEO. The DOX was either physically entrapped (PBG-eg-PEO/DOX), loaded via electrostatic interactions (PGA-eg-PEO-DOX), or covalently conjugated to the unimolecular micelles via a pH-sensitive hydrazone bond (PGA-eg-PEO-Hyd-DOX). While all these systems had a good drug loading capacity, encapsulation via electrostatic interactions yielded the highest DLC and DLE. All these systems exhibited sustained and pH-responsive drug release behavior, with slower release at physiological pH (7.4) than at pH 5.5, but PGA-eg-PEO-Hyd-DOX had the best overall pH-responsive release behavior. The versatile encapsulation and release properties of these unimolecular micelles show that they could be useful as nanocarriers for a broad range of drug release applications.
Arborescent Polypeptides for the Targeted and Controlled Release of Drugs
(University of Waterloo, 2022-01-20) Wang, Jun-Zhi; Wang, Jun-Zhi; Gauthier, Mario
Amphiphilic block copolymer micelles are commonly used as drug delivery agents, but these micelle structures tend to dissociate upon dilution. In contrast, arborescent copolymers are highly branched unimolecular micelles that remain stable under diluted conditions. This thesis work deals with the synthesis and the characterization of pH-responsive arborescent copolymer micelles containing a poly(γ-benzyl L-glutamate) (PBG) core, a poly(Nε-carbonylbenzoxy L-lysine) (PZLys) inner layer, and a poly(ethylene glycol) (PEG) shell. One of the PEG chain ends was modified with an aldehyde group to couple with the amine groups of deprotected PLys chains and form imine bonds, allowing cleavage of the PEG chains under acidic conditions. The arborescent micelles were synthesized by a generation-based grafting scheme. Linear PBG was prepared by ring-opening polymerization of γ-benzyl L-glutamate N-carboxyanhydride with n¬-hexylamine as initiator. A fraction of the benzylic protecting groups was removed with HBr, to expose free carboxylic acid groups which were coupled with the amine terminus of other PBG chains to form a generation zero arborescent structure (G0PBG). This deprotection and coupling reaction was repeated using either PBG or PZLys chains to obtain higher-generation arborescent copolymers, G0PBG-g¬-PZLys and G1PBG-g-PZLys. The protecting groups of PZLys were then removed with HBr, and the PLys segments were coupled with aldehyde-terminated PEG chains. Arborescent structures with narrow molecular weight distributions (Mw/Mn < 1.10) were obtained up to generation G2, with molecular weights increasing exponentially for successive generations. In the deprotection of the Z groups on arborescent PBG-g-PZLys, the remaining benzylic protecting groups in the PBG core were also inadvertently deprotected. As a result, dynamic light scattering (DLS) measurements in water revealed the presence of aggregated species, attributed to electrostatic intermolecular interactions between the lysine and glutamic acid units. More consistent size and zeta potential measurement were obtained in phosphate buffered saline (PBS) and 0.1 M HCl solutions, to protonate the amine and carboxyl groups of G0PBG-g-PLys. In PBS, the size and zeta potential were found to be 8.1 nm and 13 mV for G0PBG-g-PLys, and 13.6 nm and 21 mV for G1PBG-g-PLys, respectively. To avoid aggregation under conditions closer to neutrality, it is suggested that an alternate protecting group be used for the PLys chains, to allow full deprotection of the PLys chains without affecting the PBG units. Imine formation between primary amines and aldehydes was found to be difficult. When a small-molecule amine was reacted with aldehyde-terminated PEG, almost quantitative yield was achieved at room temperature without removal of the water by-product. For linear PLys, drying agents were needed to drive the equilibrium towards imine formation and only 24% of the PEG chains were coupled. For the arborescent structures only a low imine yield was achieved, even by heating and stirring with a drying agent. Lower accessibility of the amine groups is considered to be the main cause for the decreased imine formation efficiency in linear PLys and the arborescent structures.
Fluorescently Labeled Latex Particles to Monitor Film Formation
(University of Waterloo, 2017-10-25) Hisko, Victoria; Gauthier, Mario; Duhamel, Jean
The influence of the length of an oligo(ethylene glycol) spacer (EGn, where n is the number of ethylene glycol units) in a 1-pyrenemethoxy-EGn methacrylate (PyEG-MA) monomer on the incorporation of the monomer into a poly(n-butyl methacrylate) (PBMA) latex and on the diffusion of the pyrene-labeled PBMA (PyEGn-PBMA) in latex films was investigated. The PyEGn-MA monomers were prepared by two different methods. The anionic polymerization of ethylene oxide, using potassium 1-pyrenemethoxide as initiator, yielded ethoxylated 1-pyrenemethanol that was reacted with methacrylic anhydride to yield the PyEGn-MA monomer. Alternately, monotosylated well-defined ethylene glycol oligomers were successively coupled with 1-pyrenemethoxide and methacrylic anhydride. The monomers were copolymerized with n butyl methacrylate by emulsion polymerization. A longer EG7.4 spacer was found to enhance the incorporation of the PyEG7.4MA monomer up to 3.2 mol%, substantially higher that 1.9 mol% achieved previously with an EG3 spacer. The higher incorporation of PyEG7.4MA into the Py-PBMA latex led to a stronger pyrene excimer fluorescence (PEF) signal in the spectrum of the latex film. The goal was to use these fluorescently labeled particles to probe interparticle polymer diffusion (IPD) during film formation. Several issues arose in the copolymerization of PyEG7.4MA and n-butyl methacrylate (BMA). The aggregation of PyEG7.4MA into flower-like micelles was observed. Even though steps were taken to mitigate this effect in the emulsion polymerization process, the pyrene molecules tended to be more concentrated near the surface of the latex particles. This resulted in irreproducible annealing results, and it is recommended that these particles not be employed for the study of IPD.
Hydrophobic Modification of Starch
(University of Waterloo, 2019-08-27) Amos, Ryan; Gauthier, Mario
Starch is a very common polysaccharide with multiple applications in the industry, but the range of physical properties exhibited by that material is relatively limited due to its strongly hydrophilic character. The work reported in this Thesis mainly concerns the development of synthetic methods for the chemical modification of starch, either in the nanoparticle or cooked forms, with different reactive hydrophobic reagents, under conditions including solution, slurry, melt mixing and reactive extrusion, so as to introduce amphiphilic character in the materials. Starch nanoparticles (SNPs) were modified with hexanoic and propionic acid anhydrides in the presence of pyridine and 4-dimethylaminopyridine (DMAP) in dimethyl sulfoxide (DMSO) as solvent. A reaction efficiency (RE) of 100% was achieved over the entire degree of substitution (DS) range tested for both anhydrides and SNPs of different sizes. The integrity of the products was maintained, as the reaction conditions used did not lead to fragmentation of the starch and the addition of hydrophobic microdomains did not influence the Dh of the SNPs. Polyurethane prepolymers (PUPs) were synthesized from castor oil and toluene diisocyanate (TDI) without solvent at an OH:NCO ratio of 1:2. Full conversion of the hydroxyl groups was achieved, even at this low OH:NCO ratio. The castor oil PUPs were used to cross-link and add hydrophobic microdomains in thermoplastic starch (TPS) without organic solvents or catalysts in a melt mixer. The reactions proceeded with high overall RE, which would make further purification of the products unnecessary for most applications. The reaction between the starch hydroxyl and the isocyanate groups formed no by-products, with 100% atom economy. The maleation of raw linseed oil and soybean oil was completed in a benchtop pressure reactor, while reactions with soybean oil were also completed using a benchtop open glass reactor or a pilot plant scale open glass reactor. In contrast to soybean oil, the maleation of linseed oil led to extensive cross-linking. Soybean oil products were synthesized containing up to 2.6 anhydride units on average per triglyceride. Gel permeation chromatography (GPC) analysis indicated that the sealed reactor approach led to significant oligomerization, while products from both open reactor methods were predominantly isolated triglycerides. A procedure was developed to determine the weight fraction of unreacted triglycerides in the maleated oil. Hydrophobic starch esters were successfully prepared by reacting cooked starch with different cyclic anhydrides including octenyl succinic anhydride (OSA), dodecenyl succinic anhydride (DDSA), a maleated fatty acid (TENAX 2010), phthalic anhydride (PA), trimellitic anhydride (TMA), and maleated soybean oils (MSOs) in slurry reactions and in a melt mixer. Finally, hydrophobic modification by reactive extrusion was completed using DDSA, TENAX 2010, and MSO. For reactions in the dispersed phase, the RE was above 80% regardless of the anhydride loading, except for samples with high loadings of DDSA and maleated soybean oil. Reactions completed in a melt mixer with a base had a higher RE than reactions without base for all anhydride loadings. For reactive extrusion, the RE increased with the hydrophobicity of the anhydride. Reactive extrusion proved to be most advantageous to produce hydrophobically modified starch in an environmentally friendly and scalable way, with REs high enough to make purification of the products unnecessary for most applications. The results obtained show that the hydrophobic modification of starch can be achieved efficiently, using a wide range of hydrophobic reagents and reaction conditions.
Polysaccharides for Bitumen Extraction, Environmental Decontamination and Cell Culture
(University of Waterloo, 2022-02-07) Dasgupta, Natun; Gauthier, Mario
Polysaccharides are polymeric carbohydrates with long chains of monosaccharide units linked by glycosidic bonds. Some of the most prevalent polysaccharides in nature include starch and chitin. For the work reported in this thesis, amylopectin was used either in nanoparticle (fragmented) or cooked forms, while chitin was used in its deacetylated (chitosan) form. The work focuses on developing synthetic techniques to chemically modify starch and chitosan for bitumen extraction, dye degradation, and cell growth and extraction. Starch nanoparticles (SNPs) were modified with carbon disulfide in the presence of NaOH to form xanthated SNPs, which were reacted with methyl-2-bromopropionate to form novel starch-based RAFT (reversible addition-fragmentation chain transfer) macroinitiators with different degrees of substitution (DS). The starch-based RAFT agents were then used to graft thermoresponsive poly(di(ethylene glycol) methyl ether methacrylate) (PMEO2MA) onto the SNPs. RAFT polymerization was found to be an efficient method for the synthesis of thermoresponsive polymer-grafted SNPs, providing straightforward control over the number and length of grafted PMEO2MA segments, as well as the hydrophilic-lipophilic balance (HLB) of the nanoparticles in solution. Temperature-dependent solubility of the PMEO2MA-grafted SNPs was observed, as the SNPs were amphiphilic above their lower critical aggregation temperature (LCAT), forming micellar aggregates dispersed in water that were useful to extract bitumen from the sand and silt components in oil sands. The optimal SNP-g-PMEO2MA composition, structure, and concentration were determined through cycles of bitumen extraction. The addition of 0.5 M NaCl was shown to minimize the interference of fines with the extraction process, increasing the bitumen extraction efficiency to ~80% under optimal conditions. In another application, starch was used to stabilize iron nanoparticles serving in the Fenton reaction. The photocatalytic Fenton reaction uses hydrogen peroxide and Fe2+ under relatively acidic conditions (pH 2-3) to produce hydroxyl radicals as strong oxidant. The low pH, used partly to maintain solubility of the iron catalyst, is problematic because it leads to the generation of large volumes of decontaminated, yet very acidic water. Cooked starch, being hydrophilic, was investigated as a colloidal stabilizer for iron (Fe2+/Fe3+) oxide nanoparticles. The photocatalytic Fenton reaction, investigated at a pH significantly higher than usual (pH 4), enabled the efficient degradation of methylene blue. It was shown that the starch-stabilized catalysts could be reused in several degradation cycles, thereby providing an environment-friendly and cost-effective method to degrade residual dyes in water. PMEO2MA chains were also grown from chitosan films modified with RAFT-active sites of the same type used for the SNPs, thus making the chitosan films thermoresponsive. The length of the grafted PMEO2MA chains was controlled by varying the degree of substitution (DS) of the chitosan-based RAFT agent and the amount of monomer added in the grafting reaction, as determined by gel permeation chromatography (GPC) analysis of the chains cleaved from the chitosan substrates. The growth of cells on the films and their detachment at low temperatures were confirmed in cell growth studies combined with fluorescence microscopy. The reported results demonstrate that the hydroxyl groups of amylopectin starch and chitosan can be utilized to obtain novel materials useful in different application areas.
Smart Polymeric Materials by Ring-Opening Metathesis Polymerization
(University of Waterloo, 2017-09-22) Neqal, Mehdi; Héroguez, Valérie; Gauthier, Mario
The aim of this Thesis work was to address the issue of microbial contamination inside fuel tanks. Microorganisms induce the chemical corrosion of airplane tank walls due to their production of organic acids. Biocide compounds are typically used to inhibit these microorganisms, either in the form of organic small molecules, or most commonly as chromium-based coatings on the walls to hinder chemical corrosion. Organic biocides need to be replenished regularly, while chromium is a particularly dangerous compound targeted by the European Registration, Evaluation and Authorization of Chemicals (REACh) legislation due to its carcinogenic nature. A replacement approach selected for this project was the development of a smart system of multifunctional polymeric particles synthesized by dispersion ROMP, which can deliver a biocide following an acidic trigger due to the presence of microorganisms. The polymerization utilized a linear α-norbornenyl-polyglycidol macromonomer as a reactive surfactant. The hydroxyl-rich polyglycidol backbone of the macromonomer was beneficial for the conjugation of dodecylamine through a pH-sensitive imine bond and permitted the preparation of highly functionalized bioactive particles. A proof of concept for the pH sensitivity of the system was provided and the antifungal efficacy of the biocide-functionalized macromonomer and particles was verified. The particles were also integrated in a coating formulation to simulate their application on tank walls. The qualities of the original coating were preserved even after prolonged exposure to corrosive conditions, making this system viable for its foreseen application.
Synthesis and Characterization of Furan-Based Non-ionic Surfactants (FBNIOS)
(University of Waterloo, 2021-01-27) Liu, Donghan; Duhamel, Jean; Gauthier, Mario
A series of furan-based non-ionic surfactants (fbnios) derived from 5-(chloromethyl)furfural (5-CMF), a feedstock prepared by Origin Materials through a carbon negative process, were prepared from commercially available 2,5-bis(hydroxymethyl) furan (2,5-bisHMF). The fbnios were synthesized by alkylating one hydroxyl of 2,5-bisHMF by Williamson ether synthesis and ethoxylating the other hydroxyl to generate an oligo(ethylene oxide) (OEO). Through systematic variations in the OEO length achieved by anionic polymerization, and the use of octyl and dodecyl groups, fbnios with different hydrophilic-lipophilic balances (HLBs) were synthesized. The number-average degree of polymerization (DPn), and purity of the fbnios samples were determined by proton nuclear magnetic resonance (1H NMR), gel permeation chromatography (GPC), and matrix-assisted laser desorption ionization-time of flight-mass spectroscopy (MALDI-ToF-MS). The amphiphilic properties of these fbnios were characterized by surface tension and fluorescence measurements. Surface tension was applied to determine the efficiency and effectiveness of the fbnios. The critical micelle concentration (CMC) of fbnios was determined by both characterization methods. The CMC of the fbnios prepared with an octyl chain was found to decrease about 3-fold upon increasing the DPn of the OEO block from 3 to 14. The length of the OEO block had less influence on the CMC of the fbnios series prepared with a dodecyl chain. In contrast, the alkyl chain used to prepare the fbnios was found to affect their CMC, the CMC of the fbnios with an octyl chain being more than one order of magnitude larger than the CMC of the fbnios with a dodecyl chain. The range of CMC values found for the fbnios prepared in this thesis covered the range of CMCs found for well-known non-ionic surfactants (nios) such as the Triton X or Brij surfactant families. The fbnios with a dodecyl chain were found to have lower CMCs than the Brij surfactants prepared with the same alkyl chain. In summary, fbnios appear to behave as typical nios and show promising amphiphilic properties.
Synthesis of Polylactide-block-Poly(L-Lysine) Block Copolymers
(University of Waterloo, 2018-03-06) Wang, Liying; Gauthier, Mario
Polylactide (PLA) is an important biodegradable, biocompatible and renewable material that has been studied for many years for biomedical applications such as tissue scaffolding and surgical sutures. The research project described in this Thesis focused on the synthesis of polylactide-block-polylysine (PLA-b-PLy) amphiphilic block copolymers designed for use in targeted drug delivery systems. Block copolymers with a cleavable, redox-sensitive disulfide bond at the block junction, as well as non-cleavable block copolymers were synthesized for comparison. The molecular weight of the PLA and the PLy blocks in the copolymers was varied, so as to control their hydrophobic/hydrophilic balance, and ultimately their self-assembly behavior. A novel redox-sensitive initiator, tert-butyl (2-((2-hydroxyethyl)disulfanyl)ethyl) carbamate, was used to generate the redox-sensitive copolymers, whereas (3-(Boc-amino)-1-propanol served for the non-cleavable systems. The hydroxyl group of these compounds was activated with the non-metallic catalyst 1,8-diazabicyclo[5.4.0]undec-7-ene/benzoic acid (DBU/BA) to initiate the ring-opening polymerization (ROP) of lactide. After the polymerization of lactide and removal of the Boc protecting group at the end of the PLA chain, the free primary amine functionality was used to initiate the ring-opening polymerization of N6-carbobenzoxy-L-lysine N-carboxyanhydride (Z-protected L-lysine NCA monomer). Sample analysis by size exclusion chromatography (SEC) and proton nuclear magnetic resonance (1H NMR) spectroscopy confirmed that the block copolymers had low polydispersity indices (PDI) and the expected molecular weights. Deprotection of the Z-lysine units of the copolymers was accomplished with HBr, but degradation of the PLA segment could not be avoided under the reaction conditions investigated. It is suggested that future investigations either rely on a different deprotection method for the Z-group, or that a different protecting group be used in the NCA monomer serving to build the PLy block.
Using Pyrene to Probe Interparticle Polymer Diffusion in a Latex Film
(University of Waterloo, 2015-12-16) Casier, Remi; Duhamel, Jean; Gauthier, Mario
Fluorescence has been used for many years as a powerful analytical tool to probe the formation of films from aqueous latex dispersions. Currently, the most widely used method is fluorescence resonance energy transfer (FRET), which requires the use of two different fluorescently-labelled latex dispersions. As the latex particles coalesce during film formation, the amount of FRET that occurs between the particles is used to probe the level of interparticle polymer diffusion (IPD). Although FRET provides a quantitative method to probe IPD, a simpler method might only require the preparation of a single fluorescently-labelled latex using the dye pyrene. An isolated pyrene excited by a photon of light emits as a monomer. However, if the excited pyrene encounters a ground-state pyrene, it can form an excimer. The amount of excimer formed is directly proportional to the local pyrene concentration (CPy), which may be quantified by steady-state fluorescence with the ratio of the fluorescence intensity of the excimer (IE) over that of the monomer (IM), namely the IE/IM ratio. A mixture of a non-fluorescent latex with a latex consisting of polymers randomly labelled with pyrene will initially have a high CPy, generating lots of excimer and resulting in a high IE/IM ratio. As IPD occurs during film formation, the pyrene-labelled copolymer will diffuse into the surrounding non-fluorescent latex particles lowering CPy, resulting in reduced excimer formation and a decrease in the IE/IM ratio. Since variations in the IE/IM ratio reflect the extent of IPD, the IE/IM ratio was monitored over time to quantitatively describe the IPD of polymer chains between latex particles during film formation. The IE/IM ratio was used to calculate the fraction of mixing (fm) between the latex particles as a function of annealing time and temperature. The colour of the films irradiated by UV light was also monitored to determine whether a discernible colour change was apparent over the annealing process. In turn, fm was used to calculate the apparent diffusion coefficients of the pyrene-labelled copolymer. Lastly, the diffusion coefficients were used to calculate the apparent activation energy of diffusion and the c1 and c2 terms in the WLF equation.

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