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Gojmir Lahajnar

Bio: Gojmir Lahajnar is an academic researcher from Jožef Stefan Institute. The author has contributed to research in topics: Liquid crystal & Phase transition. The author has an hindex of 15, co-authored 45 publications receiving 761 citations. Previous affiliations of Gojmir Lahajnar include University of Maribor & University of Ljubljana.

Papers
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Book ChapterDOI
01 Jan 2010
TL;DR: In this paper, the authors studied the coupling interaction between liquid crystal (LC) molecules and nanoparticles (NPs) in LC=NPs mixtures and derived possible structures of the coupling term for strongly anisotropic NPs.
Abstract: We have studied the coupling interaction between liquid crystal (LC) molecules and nanoparticles (NPs) in LC=NPs mixtures. Using a simple phenomenological approach, possible structures of the coupling term are derived for strongly anisotropic NPs. The coupling terms include (i) an interaction term promoting the mutual ordering of the LC molecules and the NPs, and (ii) the Flory-Huggins-type term enforcing the phase separation. Both contributions exhibit the same scaling dependence on the diameter of the NPs. However, these terms only exist for a finite degree of nematic LC ordering. The magnetic response due to the LC-NPs coupling is probed experimentally for a mixture of weakly anisotropic magnetic NPs and a ferroelectric LC. A finite coupling effect was observed in the ferroelectric LC phase, suggesting such systems can be used as soft magnetoelectrics.

4 citations

Journal ArticleDOI
TL;DR: In this article, the temperature evolution of smectic ordering of 8CB liquid crystal confined to various CPG matrices was studied and substantial pretransitional anchoring was also observed, particularly in the silane-treated samples.
Abstract: We study the temperature evolution of smectic ordering of 8CB liquid crystal confined to various CPG matrices. The characteristic diameters of matrices ranged from 24 nm to 128 nm. The CPG voids were either left non-treated or were treated with silane. A weakly 1st order N-SmA transition in bulk 8CB, which could be attributed to the Halperin-Lubensky-Ma (HLM) effect, is broadened in confined samples. In confined samples substantial pretransitional anchoring was also observed, particularly in the silane-treated samples.

4 citations

Journal ArticleDOI
TL;DR: Atomic force microscopy images clearly showed adsorbed aggregates with a lateral dimension of approximately 40 nm and a thickness of the order of approximately 1 nm, which is very similar to the distribution of hydrodynamic radii as obtained from the dynamic light scattering experiments.

4 citations

Journal Article
TL;DR: A method for evaluating the polymer concentration profile was developed for better prediction of drug release and it was found that layers of hydrogel represent a diffusional barrier that retards the process of drugRelease.
Abstract: Layers of hydrogel represent a diffusional barrier that retards the process of drug release. For better prediction of drug release, a method for evaluating the polymer concentration profile was developed.

3 citations

Journal ArticleDOI
TL;DR: The measurements of the frequency and temperature dependence of T1rho(-1) indicate a strong effect of slowing-down of molecular translational diffusion in contact with the polymer surface and yield the average dwell-time of molecules at the surface of the order 10(-5) s.

3 citations


Cited by
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Journal ArticleDOI
TL;DR: Both simple and more complex adsorbates that are confined in various environments (slit or cylindrical pores and also disordered porous materials) are considered and how confinement affects the glass transition is addressed.
Abstract: We present a review of experimental, theoretical, and molecular simulation studies of confinement effects on freezing and melting We consider both simple and more complex adsorbates that are confined in various environments (slit or cylindrical pores and also disordered porous materials) The most commonly used molecular simulation, theoretical and experimental methods are first presented We also provide a brief description of the most widely used porous materials The current state of knowledge on the effects of confinement on structure and freezing temperature, and the appearance of new surface-driven and confinement-driven phases are then discussed We also address how confinement affects the glass transition

640 citations

Journal ArticleDOI
02 May 2012-Langmuir
TL;DR: By comparing both results of polySBMA and poly(ethylene glycol) (PEG), it is found that the hydrated water molecules on the SB unit are more tightly bound than on the ethylene glycol (EG) unit before saturation, and the additional water molecules after forming the hydration layer inpolySBMA solutions show higher freedom than those in PEG.
Abstract: The strong surface hydration layer of nonfouling materials plays a key role in their resistance to nonspecific protein adsorption. Poly(sulfobetaine methacrylate) (polySBMA) is an effective material that can resist nonspecific protein adsorption and cell adhesion. About eight water molecules are tightly bound with one sulfobetaine (SB) unit, and additional water molecules over 8:1 ratio mainly swell the polySBMA matrix, which is obtained through the measurement of T(2) relaxation time by low-field nuclear magnetic resonance (LF-NMR). This result was also supported by the endothermic behavior of water/polySBMA mixtures measured by differential scanning calorimetry (DSC). Furthermore, by comparing both results of polySBMA and poly(ethylene glycol) (PEG), it is found that (1) the hydrated water molecules on the SB unit are more tightly bound than on the ethylene glycol (EG) unit before saturation, and (2) the additional water molecules after forming the hydration layer in polySBMA solutions show higher freedom than those in PEG. These results might illustrate the reason for higher resistance of zwitterionic materials to nonspecific protein adsorptions compared to that of PEGs.

294 citations

Journal ArticleDOI
TL;DR: It is shown that there is a rather large number of theories on how cells can generate and detect electromagnetic fields and experimental evidence on electromagnetic cellular interactions in the modern scientific literature is continuously accumulating.
Abstract: Chemical and electrical interaction within and between cells is well established. Just the opposite is true about cellular interactions via other physical fields. The most probable candidate for an other form of cellular interaction is the electromagnetic field. We review theories and experiments on how cells can generate and detect electromagnetic fields generally, and if the cell-generated electromagnetic field can mediate cellular interactions. We do not limit here ourselves to specialized electro-excitable cells. Rather we describe physical processes that are of a more general nature and probably present in almost every type of living cell. The spectral range included is broad; from kHz to the visible part of the electromagnetic spectrum. We show that there is a rather large number of theories on how cells can generate and detect electromagnetic fields and discuss experimental evidence on electromagnetic cellular interactions in the modern scientific literature. Although small, it is continuously accumulating.

288 citations

Journal ArticleDOI
TL;DR: In this article, a review of the science and technological applications of ionic liquids confined in nano-pores is presented and a comprehensive overview is given about the experimental studies dealing with the changes in the physico-chemical properties of ionics like thermal phase transition, stability, dynamical behavior, optical properties etc.

258 citations

Journal ArticleDOI
TL;DR: This work aims to provide a comprehensive review discussing concepts and recent advances in the construction of antifouling sensors that are, through the use of chemical, physical, or biological engineering, capable of operating in complex sample matrix (e.g., serum).
Abstract: The ability to fabricate sensory systems capable of highly selective operation in complex fluid will undoubtedly underpin key future developments in healthcare. However, the abundance of (bio)molecules in these samples can significantly impede performance at the transducing interface where nonspecific adsorption (fouling) can both block specific signal (reducing sensitivity) and greatly reduce assay specificity. Herein, we aim to provide a comprehensive review discussing concepts and recent advances in the construction of antifouling sensors that are, through the use of chemical, physical, or biological engineering, capable of operating in complex sample matrix (e.g., serum). We specifically highlight a range of molecular approaches to the construction of solid sensory interfaces (planar and nanoparticulate) and their characterization and performance in diverse in vitro and in vivo analyte (e.g., proteins, nucleic acids, cells, neuronal transmitters) detection applications via derived selective optical or electrochemical strategies. We specifically highlight those sensors that are capable of detection in complex media or those based on novel architectures/approaches. Finally, we provide perspectives on future developments in this rapidly evolving field.

258 citations