Publications by authors named "Janis Matisons"

8 Publications

  • Page 1 of 1

Advanced Silicon Chemistry in Australia: Forming Strong Links with Asia.

Chem Asian J 2017 Jun 31;12(11):1123-1152. Epub 2017 May 31.

Associate (Research & Development: Polymer Chemistry), COOE Pty Ltd., 46/40 W Thebarton Rd, Thebarton, South Australia, 5031, Australia.

This paper details Australian commercial and academic silicon research. Areas of interest include silicon metal, polysiloxane polymers, copolymers, cyclics, emulsions, microemulsions, silanes, silane coupling agents, sol-gel chemistry and water-treatments, porous silicon, polysiloxane degradation, silicon hydrogel contact lenses, silanolate synthesis, siloxane interfacial polymerisation, hydrosilylation, polysiloxane electrolytes for lithium ion batteries, silanes for PBX materials, octafunctionalized polyhedral oligomeric silsesquioxanes (POSS), POSS hybrids, sol-gel hydrogenation catalysts, silane modification of silica, sol-gel energy storage, silicate grout stabilisation, GeoPolymer concretes, aerogel insulating foams, "Phaco-Ersatz" Accommodating Gel-Intraocular Lens technologies. Strong collaborative opportunities, in silicon, with Asia, exist with organisations such as: 1) The Asian Silicon Society and 2) The Agency for the Assessment and Application of Technology (BPPT) Indonesia.
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http://dx.doi.org/10.1002/asia.201700598DOI Listing
June 2017

Nanotubes self-assembled from amphiphilic molecules via helical intermediates.

Chem Rev 2014 Oct 7;114(20):10217-91. Epub 2014 Oct 7.

Flinders Centre for Nanoscale Science & Technology, School of Chemical and Physical Sciences, Flinders University , Adelaide, South Australia 5042, Australia.

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http://dx.doi.org/10.1021/cr400085mDOI Listing
October 2014

Chiral self-assembly of designed amphiphiles: influences on aggregate morphology.

Langmuir 2013 Aug 30;29(32):10001-10. Epub 2013 Jul 30.

Flinders Centre for Nanoscale Science & Technology, School of Chemical and Physical Sciences, Flinders University, Adelaide, South Australia, 5042, Australia.

A series of novel amphiphiles were designed for self-assembly into chiral morphologies, the amphiphiles consisting of a glutamic acid (Glu) headgroup connected through an 11-carbon alkoxy chain to a diphenyldiazenyl (Azo) group and terminated with a variable length alkyl chain (R-Azo-11-Glu, where R denotes the number of carbons in the distal chain). TEM imaging of amphiphile aggregates self-assembled from heated, methanolic, aqueous solution showed that chiral order, expressed as twisted ribbons, helical ribbons, and helically based nanotubes, increased progressively up to a distal chain length containing eight carbons, and then decreased with further increases in distal chain length. TEM and CD showed that the chiral aggregations of single enantiomers were influenced by the molecular chirality of the headgroup. However, the assembly of D,L-10-Azo-11-Glu into nanotubes demonstrated that chiral symmetry breaking effected by the azo group was also relevant to the chiral organization of the amphiphiles. The chiral order of aggregate morphologies was additionally affected by the temperature and solvent composition of assembly in a manner correlated to the mechanism driving assembly; i.e., D,L-10-Azo-11-Glu was sensitive to the temperature of assembly but less so to solvent composition, while L-14-Azo-11-Glu was sensitive to solvent composition and not to temperature. FTIR and UV-vis spectroscopic investigations into the organization of the head and azo groups, in chiral and achiral structures, illustrated that a balance of the influences of the hydrophilic and hydrophobic components on self-assembly was required for the optimization of the chiral organization of the self-assembled structures.
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http://dx.doi.org/10.1021/la401987yDOI Listing
August 2013

Chiral self-assembly of designed amphiphiles: optimization for nanotube formation.

Langmuir 2012 Oct 26;28(40):14172-9. Epub 2012 Sep 26.

Flinders Centre for Nanoscale Science & Technology, School of Chemical and Physical Sciences, Flinders University, Adelaide, Australia.

Four amphiphiles with L-aspartic acid headgroups (Asp) and a diphenyldiazenyl group (Azo) contained within the hydrophobic tails were designed and synthesized for self-assembly into helically based nanotubes. The amphiphiles of the form R'-{4-[(4-alkylphenyl)diazenyl]phenoxy}alkanoyl-L-aspartic acid (where R' is 10 or 11) varied only in alkyl chain lengths either side of the azo group, having 4, 7, or 10 carbon distal chains and 10 or 11 carbon proximal chains (R-Azo-R'-Asp, where R denotes the number of carbons in the distal chain and R' denotes the number of carbons in the proximal chain). Despite the molecular similarities, distinct differences were identified in the chiral order of the structures self-assembled from hot methanolic aqueous solutions using microscopy and spectroscopic analyses. This was reflected in dominant thermodynamic aggregate morphologies that ranged from amorphous material for 10-Azo-10-Asp, through twisted ribbons (196 ± 49 nm pitch) for 7-Azo-11-Asp, to the desired helically based nanotubes for 4- and 7-Azo-10-Asp (81 ± 11 and 76 ± 6 nm diameters, respectively). Another key variable in the self-assembly of the amphiphiles was the use of a second method to precipitate aggregates from solution at room temperature. This method enabled the isolation of thermodynamically unstable and key transitional structures. Helical ribbons were precursor structures to the nanotubes formed from 4- and 7-Azo-10-Asp as well as the wide, flattened nanotube structures (587 ± 85 nm width) found for 4-Azo-10-Asp. Overall, the results highlighted the interplay of influence of the headgroup and the hydrophobic tail on self-assembly, providing a basis for future rational design of self-assembling amphiphiles.
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http://dx.doi.org/10.1021/la3030606DOI Listing
October 2012

Aligned silane-treated MWCNT/liquid crystal polymer films.

Nanotechnology 2008 Apr 25;19(17):175602. Epub 2008 Mar 25.

Department of Materials Engineering, Monash University, Clayton VIC 3800, Australia.

We report on a method to preferentially align multiwall carbon nanotubes (MWCNTs) in a liquid crystalline matrix to form stable composite thin films. The liquid crystalline monomeric chains can be crosslinked to form acrylate bridges, thereby retaining the nanotube alignment. Further post-treatment by ozone etching of the composite films leads to an increase in bulk conductivity, leading to higher emission currents when examined under conducting scanning probe microscopy. The described methodology may facilitate device manufacture where electron emission from nanosized tips is important in the creation of new display devices.
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http://dx.doi.org/10.1088/0957-4484/19/17/175602DOI Listing
April 2008

Development of an in vitro reproductive screening assay for novel pharmaceutical compounds.

Biotechnol Appl Biochem 2008 Oct;51(Pt 2):63-71

Department of Medical Biotechnology, School of Medicine, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia.

An in vitro reproductive cell-based toxicity assay was developed using MLTC-1 (murine Leydig tumour cell line) in order to examine the reproductive toxicity of two novel nanopharmaceutical compounds, namely ethylene glycol mono allyl ether and poly(ethylene glycol) octa-functionalized polyhedral oligomeric silsesquioxane. Three commonly used cytotoxicity assays, namely the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide], MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] and Crystal Violet assays, were compared, and the MTT assay proved to be the most accurate and reproducible for the MLTC-1 cell line. The doubling rate of the MLTC-1 cells was 30+/-3.5 h and the optimal seeding density for the MTT assay was 20000 cells per well, and the optimized MTT assay utilized a 4 h cell adherence followed by incubation with 0.5 mg/ml MTT for 1 h. The intra- and inter-assay CV (coefficient of variation) values were 12.3 and 11% respectively. MLTC-1 cells only produce the reproductive hormone progesterone in response to hCG (human chorionic gonadotropin), which stimulated progesterone production dose-dependently from 0 to 100 m.i.u. (milliinternational units)/ml (2706+/-1118 ng/ml). H(2)O(2) as a negative control killed 100% of cells at 1000 microg/ml. The two nanopharmaceutical compounds were cytotoxic at concentrations > or =0.1 microg/ml, but hCG decreased cytotoxicity to > or =1000 microg/ml (P<0.001). hCG-stimulated progesterone synthesis afforded some protection against the cytotoxic effects of the two novel nanotechnology compounds; therefore doses < or =100 microg/ml and an exposure period of 1 h would be recommended for testing in in vivo animal reproductive assays.
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http://dx.doi.org/10.1042/BA20070223DOI Listing
October 2008

Ethynylbenzene monolayers on gold: a metal-molecule binding motif derived from a hydrocarbon.

J Am Chem Soc 2007 Mar 1;129(12):3533-8. Epub 2007 Mar 1.

Institute for Nanoscale Technology, University of Technology Sydney, Broadway, New South Wales, 2007, Australia.

Exposure of a Au(111) surface to ethynylbenzene in solution leads to the formation of a bound monolayer. A chemisorption process occurs to give a stable layer consisting of oxygen-containing hydrocarbon species. Ethynylbenzene itself does not oxidize under the deposition conditions indicating that the gold surface facilitates the oxidation process. Calculations show that ethynylbenzene and its oxidation products phenylacetic acid and phenyloxirane have positive binding energies to the gold surface. 1,4-Diethynylbenzene also binds to Au(111) and anchors gold nanoparticles deposited from solution to form dense, semiregular arrays.
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http://dx.doi.org/10.1021/ja064297yDOI Listing
March 2007

Synthesis and characterization of an isocyanate functionalized polyhedral oligosilsesquioxane and the subsequent formation of an organic-inorganic hybrid polyurethane.

J Am Chem Soc 2002 Nov;124(47):13998-9

Ian Wark Research Institute, University of South Australia, Mawson Lakes, South Australia 5095.

Organic-inorganic hybrids are an important class of new materials that offer improved thermal and mechanical properties over normal polymers. They may be produced by either the sol-gel route or through the use of inorganic compounds possessing reactive functional groups. Polyhedral oligosilsesquioxanes (POSS) are completely defined molecules of nanoscale dimensions that may be functionalized with reactive groups suitable for the synthesis of new organic-inorganic hybrids. Here we report the synthesis and characterization of a novel POSS possessing eight isocyanate groups via the hydrosilylation of octakis(hydridodimethylsiloxy)octasilsesquioxane (Q8M8H) and m-isopropenyl-alpha,alpha'-dimethylbenzyl isocyanate (m-TMI). The suitability of this new macromer to the synthesis of a organic-hybrids has been explored by forming a new type of highly cross-linked polyurethane elastomer via reaction of the macromer with poly(ethylene glycol) using dibutyltin dilaurate catalyst.
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http://dx.doi.org/10.1021/ja0275921DOI Listing
November 2002