Preparation of Sub-micrometer Silica Shells Using Poly(1-methylpyrrol-2-ylsquaraine)

Lynch, Daniel Ε.; Nawaz, Yasser; Boström, Thor E.

doi:10.1021/la0506933

Cited by 36 publications

(44 citation statements)

References 27 publications

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“…The average diameter is 1924 ± 45 nm, n = 116 (Table 1 entry i). The 1,924 nm average diameter for the PMPS particles studied in this paper is larger than the diameter (1,300 nm) reported previously [8].…”

Section: Characterisation Of the Templatecontrasting

confidence: 74%

“…Preparation of silica and iron-silica hollow spheres These hollow spheres were prepared using the same procedure as described by Lynch et al [8], except that during the acid hydrolysis stage, the silicated particles were suspended in a solution of iron(II) chloride (1.00 g, 3.7 mmol) in HCl (30 mL, 0.1 M) to prepare the iron-silica hollow spheres.…”

Section: Methodsmentioning

confidence: 99%

“…The sacrificial core process is one of the most frequently used techniques to produce hollow inorganic spheres [1][2][3][4][5][6][7][8][9][10][11][12]. The sacrificial core approach involves the use of a solid organic or inorganic spherical particle as the template.…”

Section: Introductionmentioning

confidence: 99%

“…The core-shell structure is produced by coating the core with inorganic precursors or nanoparticles which are crosslinked to form the shell. Hollow spherical particles are subsequently generated by removing the template from the core-shell structure thermally [1][2][3][4][5][6][7][8][9][10] or chemically [1-3, 11, 12].…”

Section: Introductionmentioning

confidence: 99%

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Characterisation of hollow Russian doll microspheres

Begum

Jones

Jiao³

et al. 2010

J Mater Sci

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Poly(1-methylpyrrol-2-yl)squaraine (PMPS) particles have been characterised using SEM. The PMPS particles were used as templates to prepare bare silica and iron-silica hollow spheres, which were characterised using TEM and SEM. The PMPS particles and the hollow spheres are not uniformly sized and are agglomerated. The hollow spheres with larger diameters ([900 nm) contain an internal 'Russian doll' structure. The iron-silica hollow spheres are fused to one another, and the hollow spheres have a heterogeneous wall thickness. The silica and ironsilica hollow spheres both aggregate by size. There are two different size populations (for the diameter) of the bare silica and iron-silica hollow spheres. The smaller silica spheres have thinner walls compared to the larger silica hollow spheres. The larger silica hollow spheres and the iron-silica hollow spheres have similar wall thicknesses. The iron compound in the iron-silica hollow spheres has an oxidation state of 3? and is crystalline.

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Section: Characterisation Of the Templatecontrasting

confidence: 74%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Characterisation of hollow Russian doll microspheres

Begum

Jones

Jiao³

et al. 2010

J Mater Sci

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“…Previous SEM images (Begum et al, 2010;Lynch et al, 2005), plus the image in Figure 1, indicate that the surface of PMPS particles is relatively featureless. This is also evident in Figure 4 where little can be gained on the size and shape of the pore openings.…”

Section: Surface Analysismentioning

confidence: 92%

The uptake of metal elements into poly(1-methylpyrrol-2-ylsquaraine) particles and a study of their porosity

Lynch¹,

Bennett

Bateman

et al. 2016

Adsorption Science & Technology

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The article reports an experimental study of the metal uptake properties of poly(1-methylpyrrol-2-ylsquaraine) particles, in the context of 51 elemental metal complexes. Vagaries of the experimental results meant that the final analysis took place for 43 of these metals. After an initial descriptive analysis, an Analysis of Variance model was fitted. This revealed that several factors, some intrinsic to the metals themselves, others relating to the experimental conditions, have an important influence on the adsorption characteristics of the poly(1-methylpyrrol-2-ylsquaraine) particles. Of these, the most important is the ratio of the number of moles of the metal to the number of moles of the adsorbent particles. X-ray mapping of the poly(1-methylpyrrol-2-ylsquaraine) particles treated with contrast agent revealed that, although adsorption was all throughout the particles, the majority of the agent was adsorbed within 10-15% (diameter distance) of the surface of the particles.

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Self‐Assembly of Tripodal Squaraines: Cation‐Assisted Expression of Molecular Chirality and Change from Spherical to Helical Morphology

2006

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Inspired by the elegance and complexity of natural helical assemblies, from the nanoscopic DNA double helix and collagen triple helix to microscopic viruses and macroscopic sea shells, chemists have been trying to mimic the structure and functions of biological macromolecules in self-assembled synthetic molecules. [1][2][3][4][5][6][7] The most challenging task in these studies is the control of the overall morphology and the supramolecular chirality of the selfassembled architectures within the nanometer-to-micrometer length scale.[8] Although a few reports on reversible morphology transitions caused by external stimuli have appeared, [9] a spherical-to-helical change induced by a cation was previously unknown. However, in an interesting report Nolte and co-workers described the loss of helicity in a phthalocyanine-derived self-assembly in the presence of potassium ions.[10] Herein we report an unprecedented self-assembly of tripodal squaraine dyes, which form vesicular structures upon evaporation of the solvent from a solution of the dye and helical architectures through the expression of molecular chirality into supramolecular helicity upon a specific cation binding. [11] The supramolecular chemistry of functional dyes is at center stage in the "bottom-up" creation of nanoarchitectures.[12] Squaraines, a class of zwitterionic dyes, are well known for their tendency to form aggregates under the influence of certain solvent mixtures and cations. [13,14] Although these dyes have been studied extensively owing to their fundamental and technological significance, they are rarely exploited for the crafting of supramolecular architectures. The propensity of these dyes to aggregate to form hierarchical assemblies could be enhanced by confining the chromophores to an aromatic platform, thereby making interchromophore interaction possible. As a proof of principle of this hypothesis, we designed the three tripodal squaraines 1 a-c, which we then synthesized by the reaction of 1,3,5-tris(2-(N-methyl-N-phenylamino)ethoxy)benzene with the corresponding N,N-(dialkylaminophenyl)-4-hydroxycyclobut-3-ene-1,2-dione and characterized by spectral analysis. The UV/Vis spectra of these dyes show strong absorption but weak emission. For example, 1 c has an absorption maximum in chloroform at 647 nm (6.2 10 À7 m, e 651 nm = 8.9 10 5 m À1 cm À1 ) with a shoulder at 617 nm, whereas in acetonitrile, in addition to the l max absorption at 651 nm (8.3 10 À7 m, e 651 nm = 2.5 10 5 m À1 cm À1 ) and the shoulder at 614 nm, another band was observed at 578 nm. The emission maximum of 1 c when excited at 570 nm in chloroform or acetonitrile occurred at 662 and 663 nm with quantum yields of 0.01 and 0.004, respectively (relative to bis(4-(dimethylamino)phenyl)squaraine in chloroform as the standard). These observations support intramolecular chromophore interaction in acetonitrile and the consequent exciton coupling of the confined chromophores. [15] The absorption spectra of 1 a-c in acetonitrile-water mixtures of different compositions showed ...

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Preparation of Sub-micrometer Silica Shells Using Poly(1-methylpyrrol-2-ylsquaraine)

Cited by 36 publications

References 27 publications

Characterisation of hollow Russian doll microspheres

Characterisation of hollow Russian doll microspheres

The uptake of metal elements into poly(1-methylpyrrol-2-ylsquaraine) particles and a study of their porosity

Self‐Assembly of Tripodal Squaraines: Cation‐Assisted Expression of Molecular Chirality and Change from Spherical to Helical Morphology

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