SVIBOR - Project code: 1-07-223

MINISTRY OF SCIENCE AND TECHNOLOGY

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tel.: +385 1 459 44 44, fax: +385 1 459 44 69
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Project code: 1-07-223

NEW METHOD OF CRYSTAL GROWTH FROM SOLUTION AND AGGREGATION OF COLLOIDS

Main researcher: STUBIČAR, NADA (45320)

Assistants

Type of research: basic
Duration from: 01/01/91. to 12/31/95.

Papers on project (total): 1

Institution name: Prirodoslovno-matematički fakultet, Prirodoslovni odjeli, Zagreb (119)
Department/Institute: Chemistry Department, Laboratory of Physical Chemistry.
Address: Marulićev trg 19/II. p.p.163
City: 41000 - Zagreb, Croatia

Communication: Phone: 385 (0)1 446 528, 446 001.; Fax: 385 (0)1 446 528.; E-mail: ¦AćTO GA NEMAM?; E-mail: stubiźar@phy.hr

Summary: The research undertaken in the time period between 1.1.1991 and 31.8.1995 is in accordance to the Proposal of the project: "New method of Crystal Growth from Solution and Aggregation of Colloids". As it is shown in the next paragraphs the program of investigation is unique in our country regarding the contents and the approach. The systems: lead and lanthanum fluorides, nonionic surfactant Triton X-100, polyelectrolyte diC8-lecithin, and the others, and the results obtained are also interesting from the practical point of view. The experimental and the theoretical approach are well based on modern experimental techniques: the constant composition method for kinetic measurements and dynamic light scattering method with appropriate software for particle characterization, with employing not long ago purchased instrument DLS-3700 spectrophotometer (Otsuka, Japan), which was started to be used successfully by me in this period. I am the only worker for this project and the results are published in 12 papers: 5 papers published in journals plus 1 accepted for publication in the international journal, 6 papers in Proceedings of the Conferences: 1 international and 5 domestic conferences with international participants (written in engl.), 1 paper submitted for publication, 8 abstracts i Books of Abstracts with similar subjects as are in the papers, and 4 B.Sc. Theses headed by me (defended in this period), whose subject is also part of this project. Because of all this I would expect better financial support for material costs and the support for one young researcher.

Keywords: Adsorption on solid/liquid interfaces, Activity product(s) of lead fluorides, Characterization methods by - FTIR spectroscopy, - polarization microscopy, - R”ntgen diffraction analysis, Coatings, Crystal growth by - constant composition method, - pF-stat method, Dynamic light scattering, Hydrodynamic diameter(s), Isotopic effect, Kinetics of crystal growth from solution, Lead fluoride phases - alpha PbF2, - beta PbF2, Micelles, Micellization, Microhardness, Microstructure, Morphology of crystals (habit), Nonionic surfactant Triton X-100, Particle size distribution, Radius of gyration, Salt effect, Separation of phases in liquid/liquid system, bimodal curves, Static light scattering, Supersaturation - computer calculation.

Research goals: Scope of this research was to gather further information about state, transport and transformation of materials through the processes at interfaces: i) solid/liquid in complicated solutions due to hydrolysis of ions at dynamic conditions of steady-state, ii) liquid/liquid in dilute solutions of nonionic surfactant and polyelectrolyte, micellization, vesicule formation iii) solid/solid, microstructure of coatings, synthesis of B-W compounds by sintering due to the high-energy ball-milling. i) In this period (1991-5) we continued to study lead fluorides (2, 8, A1,3,4,6,7,8), and started lanthanum fluorides (A2). From the fundamental point of view the results get insight into the mechanism and kinetics of ionic crystal growth from constant supersaturated solutions during the whole process of growth, which enables the preparation of metastable phases, intermediate phases, and some phases which are formed only at microscopic concentration levels using classical growth procedure. The practical point of view is also very important: manufacture of metallic glasses, because of their optical properties (transparency, anisotropy) in spectroscopy and electronics, because of ion conducting properties (as superionics) etc. Using the pF-stat method we prepared alpha-, beta-PbF2 and some unidentified structure of lead fluoride crystals of various size: going from colloidal (which may have different properties, new interesting area of investigations), to microcrystals (above 100 microns), having desired habit and size distribution. It is known that kinetics of growth can be affected by inhibitors/promoters. Sometimes it is desirable that such additive does not incorporate into crystal structure i.e. that its adsorption is physical in nature, reversible. We chose to use as an inhibitor/promoter the nonionic surfactant Triton X-100 (A4, A6,A7, A8 and two manuscripts, one accepted and one submitted). ii) The determination of particle size and size distribution of nonionic surfactant Triton X-100 (particles of about 10 nm in diameter) is interesting because of its application in industry:as detergent, stabilizer, flocculant, solubilizer, etc. (6, A4, A7). The micellization of diC8-lipid as a function of concentration, temperature and D2O/H2O volume ratio was studied by DLS experimentally and theoretically (3, A5); it is a part of a project at Massachusetts Institute of Technology, Cambridge. iii) The coatings on some metallic surfaces were prepared and its properties studied, using quantitative transmission microscopy with the tendency to improve their properties and application. Systems studied were: refractory carbide powders on some steel rods prepared by using home-made equipment with a rotating electric arc (1) and copper coated aluminum plates prepared by magnetron sputtering technique (7), tungsten borides W2B, WB and WB4 synthesized by high-energy ball-milling and characterized by X-ray diffraction analysis (4,9), and structural changes in ZrO2-Y2O3-MgO mixture caused by the same treatment (10), as well as the deamalgamation process of silver-tin-base amalgams (dentistry amalgam scraps and the model Ag70-Sn17-Cu13 alloy), (5,11).

COOPERATION - PROJECTS

Name of project: Water Micellar Solutions
Name of institution: Department of Nuclear Engineering, Massachusetts Institute of Technology, USA
City: 02139 - Cambridge, Massachusetts,USA
Name of project: Water Micellar Solutions
Name of institution: Department of Chemistry, University of Florence
City: Firenze, Italy
Name of project: Untersuchungen der micellischen Eigenschaften der nicht-ionischen Tensiden mit Licht und Roentgen-klein-Winkel Streuungen
Name of institution: Institut fur physikalische Chemie der Universitat Graz
City: 8010 - Graz, Austrija
Name of project: Karakterizacija polimernih otopina
Name of institution: Komikro d.o.o.
City: 41000 - Zagreb, Croatia

COOPERATION - INSTITUTIONS

Name of institution: Department of Nuclear Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Type of institution: State institute
Type of cooperation: Joint publishing of scientific papers
City: 02139 - Cambridge, Massachusetts,USA
Name of institution: Department of Chemistry, University of Firenze, Firenze, Italy.
Type of institution: University/Faculty
Type of cooperation: Joint publishing of scientific papers
City: Firenze, Italy
Name of institution: Institut fur physikalische Chemie der Universitat Graz
Type of institution: University/Faculty
Type of cooperation: Joint publishing of scientific papers
City: A-8010 - Graz, ™sterreich, Austria
Name of institution: Komicro d.o.o.
Type of institution: Economical/Production
Type of cooperation: Occasional exchange of information
City: 41000 - Zagreb, Croatia

Other information about the project.


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Last update: 10/26/95
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