Wettability and Other Surface Properties of Modified Polymers

Surface wettability is one of the crucial characteristics for determining of a material’s use in specific application. Determination of wettability is based on the measurement of the material surface contact angle. Contact angle is the main parameter that characterizes the drop shape on the solid surface and is also one of the directly measurable properties of the phase interface. In this chapter, the wettability and its related properties of pristine and modified polymer foils will be described. The wettability depends on surface roughness and chemical composition. Changes of these parameters can adjust the values of contact angle and, therefore, wettability. In the case of pristine polymer materials, their wettability is unsuitable for a wide range of applications (such as tissue engineering, printing, and coating). Polymer surfaces can easily be modified by, e.g., plasma discharge, whereas the bulk properties remain unchanged. This modification leads to oxidation of the treated layer and creation of new chemical groups that mainly contain oxygen. Immediately after plasma treatment, the values of the contact angles of the modified polymer significantly decrease. In the case of a specific polymer, the strongly hydrophilic surface is created and leads to total spreading of the water drop. Wettability is strongly dependent on time from modification

Physicochemical Properties of Gold Nanostructures Deposited on Glass

Properties of gold films sputtered onto borosilicate glass substrate were studied. UV-Vis absorption spectra were used to investigate optical parameters. XRD analysis provided information about the gold crystalline nanostructure, the texture, and lattice parameter and biaxial tension was also determined by the XRD method. The surface morphology was examined by atomic force microscopy (AFM); chemical structure of sputtered gold nanostructures was examined by X-ray photoelectron spectroscopy (ARXPS). The gold crystallites are preferentially [111] oriented on the sputtered samples. Gold deposition leads to dramatic changes in the surface morphology in comparison to pristine glass substrate. Oxygen is not incorporated into the gold layer during gold deposition. Experimental data on lattice parameter were also confirmed by theoretical investigations of nanoclusters using tight-binding potentials

Application of a 2D Molybdenum Telluride in SERS Detection of Biorelevant Molecules

Two-dimensional (2D) transition-metal dichalcogenides have become promising candidates for surface-enhanced Raman spectroscopy (SERS), but currently very few examples of detection of relevant molecules are available. Herein, we show the detection of the lipophilic disease marker beta-sitosterol on few-layered MoTe2 films. The chemical vapor deposition (CVD)-grown films are capable of nanomolar detection, exceeding the performance of alternative noble-metal surfaces. We confirm that the enhancement occurs through the chemical enhancement (CE) mechanism via formation of a surface-analyte complex, which leads to an enhancement factor of approximate to 10(4), as confirmed by Fourier transform infrared (FTIR), UV-vis, and cyclic voltammetry (CV) analyses and density functional theory (DFT) calculations. Low values of signal deviation over a seven-layered MoTe2 film confirms the homogeneity and reproducibility of the results in comparison to noble-metal substrate analogues. Furthermore, beta-sitosterol detection within cell culture media, a minimal loss of signal over 50 days, and the opportunity for sensor regeneration suggest that MoTe2 can become a promising new SERS platform for biosensing.Peer reviewe

Kovalentní molekulárně imprintované polymery pro selektivní adsorpci stimulátoru růstu rostlin 1-naftalenoctové kyseliny

In this work, we present the development and testing of new sorption materials for the adsorption of 1-naphta-leneacetic acid (NAA). Covalently prepared molecularly imprinted polymers (MIPs) were prepared as suitable materials. Molecular imprinting was performed using two different NAA derivatives: 4-vinylbenzyl 2-(naph-thalen-1-yl)acetate and N-methyl-2-(naphthalen-1-yl)-N-((4-vinylbenzoyl)oxy)acetamide. The prepared mono-mers bearing NAA fragment were subjected to polymerization, removal of template and the prepared MIPs were further characterized and tested. Both types were able of MIPs to catch out > 98% NAA from solution (10(-3) mol L-1) within 10 min and subsequently desorb it quantitatively. Both types of prepared MIPs can be used in at least 10 consecutive adsorption/desorption cycles. Ester-derived MIPs were also highly effective for continuous flow adsorption of 10(-2) mol L(-1 )NAA and showed certain level of selectivity for NAA in a mixture with anthranilic acid and/or salicylic acid.V této práci představujeme vývoj a testování nových sorpčních materiálů pro adsorpci 1-naftalenoctové kyseliny (NAA). Jako vhodné materiály byly připravené molekulárně imprintované polymery (MIPs). Molekulární imprintování bylo provedeno s využitím dvou různých NAA derivátů: 4-vinylbenzyl-2-(naftalen-1-yl)acetátu a N-methyl-2-(naftalen-1-yl)-N-((4-vinylbenzoyl)oxy)acetamidu. Připravené monomery nesoucí NAA fragment byly podrobeny polymeraci, odstranění templátu a připravené MIPs byly dále charakterizovány a testovány. Oba typy MIPs byly schopny zachytit >98% NAA z roztoku (10(–3) mol L-1) během 10 minut a následně ji kvantitativně desorbovat. Oba typy připravených MIPs mohou být použity v 10 po sobě jdoucích cyklech adsorpce/desorpce. MIP odvozené od esterů byly také vysoce účinné pro kontinuální průtokovou adsorpci 10(-2) mol L(-1)NAA a vykazovaly určitou úroveň selektivity pro NAA ve směsi s kyselinou anthranilovou a/nebo kyselinou salicylovou

Přeměna vodivých polypyrrolových nanostruktur na uhlíky s obsahem dusíku a její vliv na adsorpci organického barviva

New types of materials were produced by gradual heating of a conducting polymer, polypyrrole, to elevated temperatures. Three polymers differing in morphology - globules, nanofibers, and nanotubes - were exposed to temperatures from 100 to 700 degrees C in an argon atmosphere. The yields always exceeded 50 wt%, and the morphological features of the polymer were preserved. The transformation of polypyrrole salts to the corresponding bases followed by the carbonization was monitored by FTIR spectroscopy. The elemental analysis confirmed the subsequent conversion of polypyrrole to nitrogen-containing carbon. The specific surface areas were of the order of tens of m(2) g(-1); they increased from globules to nanotubes and nanofibers but were virtually independent of the exposition temperature. The conductivity of the powders was compared with that of the pellets when their preparation was possible. As the temperature was increased up to 400 degrees C, the conductivity decreased for all samples by ca. 5 orders of magnitude, e.g., for nanofibers from 10 to 10(-4) S cm(-1) but recovered to 10(-1) S cm(-1) after the subsequent carbonization up to 700 degrees C. Polypyrroles exposed to various temperatures were then tested for the adsorption of organic dye, Reactive Black 5, from water. The dye adsorption on original polypyrroles strongly depended on the polymer morphology. Polypyrrole nanofibers were able to remove the dye completely with a capacity of 100 mg g(-1), while the adsorption on polypyrrole globules was poor. The adsorption efficiency thus increased from globules to nanotubes and nanofibers. The adsorption performance was reduced after the carbonization, but the general trends were preserved.Postupným zahříváním vodivého polymeru polypyrrolu na zvýšené teploty byly vyráběny nové typy materiálů. Tři polymery lišící se morfologií - globule, nanovlákna a nanotrubice - byly vystaveny teplotám od 100 do 700 °C v argonové atmosféře. Výtěžky vždy přesáhly 50 % hm. a morfologické vlastnosti polymeru byly zachovány. Transformace polypyrrolových solí na odpovídající báze s následnou karbonizací byla sledována pomocí FTIR spektroskopie. Elementární analýza potvrdila následnou konverzi polypyrrolu na uhlík obsahující dusík. Specifické povrchy byly řádově desítky m(2) g(-1); zvýšily se z globulí na nanotrubice a nanovlákna, ale byly prakticky nezávislé na teplotě expozice. Vodivost prášků byla srovnávána s vodivostí pelet, pokud byla možná jejich příprava. Když se teplota zvýšila až na 400 °C, vodivost se u všech vzorků snížila o cca. 5 řádů, např. pro nanovlákna od 10 do 10(-4) S cm(-1), ale obnovena na 10(-1) S cm(-1) po následné karbonizaci až do 700 °C. Polypyrroly vystavené různým teplotám následně byly testovány na adsorpci organického barviva, Reactive Black 5, z vody. Adsorpce barviva na původních polypyrrolech silně závisela na morfologii polymeru. Polypyrrolová nanovlákna dokázala barvivo úplně odstranit s kapacitou 100 mg g(-1), zatímco adsorpce na polypyrrolové globule byla špatná. Adsorpční účinnost se tak zvýšila z globulí na nanotrubice a nanovlákna. Adsorpční výkon byl po karbonizaci snížen, ale obecné trendy byly zachovány

Interaction of human osteoblast-like Saos-2 and MG-63 cells with thermally oxidized surfaces of a titanium-niobium alloy.

An investigation was made of the adhesion, growth and differentiation of osteoblast-like MG-63 and Saos-2 cells on titanium (Ti) and niobium (Nb) supports and on TiNb alloy with surfaces oxidized at 165°C under hydrothermal conditions and at 600°C in a stream of air. The oxidation mode and the chemical composition of the samples tuned the morphology, topography and distribution of the charge on their surfaces, which enabled us to evaluate the importance of these material characteristics in the interaction of the cells with the sample surface. Numbers of adhered MG-63 and Saos-2 cells correlated with the number of positively-charged (related with the Nb2O5 phase) and negatively-charged sites (related with the TiO2 phase) on the alloy surface. Proliferation of these cells is correlated with the presence of positively-charged (i.e. basic) sites of the Nb2O5 alloy phase, while cell differentiation is correlated with negatively-charged (acidic) sites of the TiO2 alloy phase. The number of charged sites and adhered cells was substantially higher on the alloy sample oxidized at 600°C than on the hydrothermally treated sample at 165°C. The expression values of osteoblast differentiation markers (collagen type I and osteocalcin) were higher for cells grown on the Ti samples than for those grown on the TiNb samples. This was more particularly apparent in the samples treated at 165°C. No considerable immune activation of murine macrophage-like RAW 264.7 cells on the tested samples was found. The secretion of TNF-α by these cells into the cell culture media was much lower than for either cells grown in the presence of bacterial lipopolysaccharide, or untreated control samples. Thus, oxidized Ti and TiNb are both promising materials for bone implantation; TiNb for applications where bone cell proliferation is desirable, and Ti for induction of osteogenic cell differentiation

Correlation of relative numbers of human osteoblast-like Saos-2 and MG-63 cells, i.e. <i>N^rel(Saos 2)</i> (a), <i>N^rel(MG 63)</i> (b), mean surface roughness <i>R_a</i> (1 and 10 µm cut off) (c) and zeta (<i>ς</i>-) potential (d) with the relative concentration of oxygen <i>Δc(O)</i> on the surface of Ti, Nb and TiNb samples treated at 165°C or 600°C.

<p>Experiments on day 1 and day 3 are graphically distinguished. Data are presented as mean ± S.E.M. from 32 measurements (cell number) or 2 measurements (ζ- potential) for each experimental group and time interval.</p

Atomic force microscopy (AFM) images (1×1 µm) of metallic samples treated at 165°C or 600°C, namely <i>Ti165</i> (A), <i>TiNb165</i> (B), <i>Ti600</i> (C), <i>TiNb600</i> (D), and <i>Nb165</i> (E).

<p>Atomic force microscopy (AFM) images (1×1 µm) of metallic samples treated at 165°C or 600°C, namely <i>Ti165</i> (A), <i>TiNb165</i> (B), <i>Ti600</i> (C), <i>TiNb600</i> (D), and <i>Nb165</i> (E).</p