A. S. Nuraeva

Morphology and Piezoelectric Properties of Diphenylalanine Microcrystals Grown from Methanol-Water Solution

Morphology and piezoelectric properties of diphenylalanine microcrystals grown by drying the droplet of methanol and water mixture in various proportions have been studied. We have found that the increase of water concentration leads to the significant change of the microcrystal morphology from flat dendrite structures to elongated microcrystals: microtubes and microrods. The effect was attributed to increasing of the drying time. The morphology of the dendrite structures was revealed and empirical dependence of the dendrite thickness on diameter was found. Finally, the piezoelectric activity of the microtubes was demonstrated using the piezoresponse force microscopy.

Piezoelectric and ferroelectric properties of organic single crystals and films derived from chiral 2-methoxy and 2-amino acids

ABSTRACT Local piezoelectric and ferroelectric properties as well as morphology of single crystals and films of two novel chiral organic compounds derived from chiral 2-methoxy and 2-amino acids have been investigated. The crystals demonstrated piezoelectric response exceeding that of lithium niobate. The piezoelectric response was registered also in compound films. Piezoelectric properties and domain structure of single crystals and films have been studied by piezoresponse force microscopy.

Patterning and nanoscale characterization of ferroelectric amino acid beta-glycine

The formation of self-organized micro- and nano-islands of beta-glycine prepared by spin-coating is observed. It is shown that the islands are very stable and possess apparent piezoelectric and ferroelectric properties studied in detail by Piezoresponse Force Microscopy. The micro-Raman studies are conducted to confirm the crystallographic preferred orientation and formation of β-phase. The polarization reversal of individual ferroelectric islands is demonstrated by application of the relatively small bias voltage.

Morphology and piezoelectric characterization of thin films and microcrystals of ortho-carboranyl derivatives of (S)-glutamine and (S)-asparagine

ABSTRACT Local morphological features and piezoelectric properties of films and bulk crystals of ortho-carboranyl derivatives of (S)-asparagine and (S)-glutamine have been investigated at nanoscale by atomic force and piezoresponse force microscopies. Both films and bulk crystals of the studied compounds demonstrated a very high piezoelectric response exceeding that of lithium niobate. The crystal structure has been studied by single crystal X-ray diffraction.

Synthesis and piezoelectric properties of N -phthaloylglutamic acid derivatives

The (S,S)- and (R,R)-enantiomers of dimethyl 2,4-diphthalimidoglutarate were synthesized by nucleophilic substitution of bromine in dimethyl (2S,4RS)-4-bromo-N-phthaloyl-glutamate upon treatment with potassium phthalimide, followed by separation. The crystal structure of the obtained compounds was studied by X-ray diffraction. Crystals of enantiomerically pure dimethyl 4-hydroxy- and 4-phthalimido-N-phthaloylglutamates were found to possess a noticeable piezoelectric activity.

Spin coating formation of self-assembled ferroelectric β-glycine films

ABSTRACT The formation of self-assembled ferroelectric glycine films of various morphologies by spin coating technique was investigated. The film morphology varied from dendritic feather-like structure to arrays of individual micro- and nanoislands and 15 nm-thick layers. It was confirmed by confocal Raman microscopy that most of the films belonged to ferroelectric beta phase. Piezoelectric properties and domain structure of the films were studied by piezoresponse force microscopy.

Piezoactive amino acid derivatives containing fragments of planar-chiral ortho-carboranes

A series of novel (S)-amino acid derivatives bearing planar-chiral (3-acylamino-1,2-dicarba-closo-dodecaboran-1-yl)acetyl substituents was synthesized. Carboranyl amino esters were obtained in a diastereomerically pure form (according to chiral HPLC). Single crystals of individual diastereomers were studied by optical microscopy, X-ray diffraction analysis and piezoresponse force microscopy. The piezoelectric activity of some compounds was shown to exceed that of most known organic piezoelectrics.

Piezoelectric properties and Young's moduli of diphenylalanine microtubes—oxide nanoparticles composites

ABSTRACT In this work, we investigated the influence of piezoelectric ZnO and nonpiezoelectric SiO2 and TiO2 nanoparticles on the structure and some physical properties of composite structures based on microtubes of diphenylalanine. We demonstrated that all types of used nanoparticles promoted formation of voids and cavities in diphenylalanine microtubes thus reducing the effective Youngs modulus and lateral piezoelectric coefficient of the composite. At the same time, embedding of piezoelectric ZnO nanoparticles provides noticeable vertical piezoresponse normally absent in single-component diphenylalanine microtubes. The obtained results demonstrate the ability to control the properties of self-assembling composite biomaterials by nanoparticles.