Table of Contents

Colloid. Interface., Volume 1, Issue 1 (March 2018)

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Readerexternal link to open them.
View options order results:
result details:
Displaying articles 1-7
Export citation of selected articles as:

Research

Jump to: Review

Open AccessFeature PaperArticle Surface Tension Measurements with the Drop Profile Analysis Tensiometry—Consideration of the Surfactant Mass Balance in a Single Drop
Colloid. Interface. 2018, 1(1), 1; doi:10.3390/colloids1010001
Received: 3 August 2017 / Revised: 23 August 2017 / Accepted: 29 August 2017 / Published: 1 September 2017
Cited by 1 | PDF Full-text (1228 KB) | HTML Full-text | XML Full-text
Abstract
In drop profile analysis tensiometry, the ratio of drop surfaces area S to volume V is large, i.e., S/V >> 1. In such a case, the concentration of a surfactant within the drop bulk decreases due to adsorption at the drop surface. In
[...] Read more.
In drop profile analysis tensiometry, the ratio of drop surfaces area S to volume V is large, i.e., S/V >> 1. In such a case, the concentration of a surfactant within the drop bulk decreases due to adsorption at the drop surface. In contrast, in bubble profile analysis tensiometry, we have S/V << 1 so that depletion due to adsorption is negligible. A protocol is presented to determine the correct adsorption parameters of surfactants from surface tension data measured by bubble and drop profile analysis tensiometry. The procedure is applied to experimental data measured for selected surfactants of different adsorption activities: C10OH, CTAB, Tween 20, and the equimolar mixture SDS + DoTAB. The results show that for surfactants with higher surface activity, the differences between the surface tensions measured with the drops and bubbles profile analysis tensiometry, respectively, are larger, while for less surface-active surfactants, such as SDS, the results obtained from drop and bubble profile experiments are very close. The correction procedure is based on the same set of adsorption parameters used to fit both the experimental data obtained from drop-based measurements (which involve the depletion effects) and those data measured in a way that depletion effects are negligible. Full article
(This article belongs to the Special Issue Selected Papers from Bubble & Drop 2017)
Figures

Open AccessArticle Decontamination of Uranium-Polluted Groundwater by Chemically-Enhanced, Sawdust-Activated Carbon
Colloid. Interface. 2018, 1(1), 2; doi:10.3390/colloids1010002
Received: 21 September 2017 / Revised: 11 October 2017 / Accepted: 11 October 2017 / Published: 14 October 2017
PDF Full-text (5332 KB) | HTML Full-text | XML Full-text
Abstract
The preparation of highly efficient and low-cost activated carbon from sawdust was achieved for the treatment of uranium-contaminated groundwater. The adsorption properties of the synthesized activated carbon, as well as their ability to be reused, were assessed. The obtained results demonstrated that sawdust
[...] Read more.
The preparation of highly efficient and low-cost activated carbon from sawdust was achieved for the treatment of uranium-contaminated groundwater. The adsorption properties of the synthesized activated carbon, as well as their ability to be reused, were assessed. The obtained results demonstrated that sawdust activated carbon (SDAC) and its amine form (SDACA) had high affinity towards uranium ions at pH values of 4.5 and 5 for SDAC and SDACA, respectively. The experimental results showed that the maximum adsorption capacity of uranium was 57.34 and 76.7 mg/g for SDAC and SDACA, respectively. A maximum removal efficiency of 89.72% by SDAC and 99.55% by SDACA were obtained at a solid/liquid ratio of 8 mg/mL. The removal mechanism of uranium by SDAC and SDACA was suggested due to interaction with the amine and carboxylic groups. The validation of the method was verified through uranium separation from synthetic as well as from groundwater collected from water wells in the Wadi Naseib area, Southwestern Sinai, Egypt. Full article
Figures

Open AccessArticle Nanostructured Assemblies of Gold and Silver Nanoparticles for Plasmon Enhanced Spectroscopy Using Living Biotemplates
Colloid. Interface. 2018, 1(1), 4; doi:10.3390/colloids1010004
Received: 19 September 2017 / Revised: 31 October 2017 / Accepted: 1 November 2017 / Published: 4 November 2017
PDF Full-text (4078 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The ability to control the assembly of nanoparticles on substrates used in plasmon-enhanced spectroscopy continues to drive research in the field of nanofabrication. Here we describe the use of fungi as soft biotemplates to fabricate nanostructured microtubules with gold and gold-silver nanoparticles with
[...] Read more.
The ability to control the assembly of nanoparticles on substrates used in plasmon-enhanced spectroscopy continues to drive research in the field of nanofabrication. Here we describe the use of fungi as soft biotemplates to fabricate nanostructured microtubules with gold and gold-silver nanoparticles with potential applications as sensors and biosensors. In the first step, spores of the filamentous fungus Cladosporium sphaerospermum were inoculated in a suspension of gold nanoparticles, forming stable microtubules of gold nanoparticles during fungus growth. These materials were exposed to a second suspension of silver nanoparticles, resulting in complexes multilayers structures of gold and silver nanoparticles, which were evaluated as substrates for surface-enhanced Raman scattering (SERS) using small amounts of thiophenol as probe molecules directly on the microtubules. Both gold and the gold-silver substrates provide the SERS effect. Full article
Figures

Open AccessArticle Multi-Target Inhibition of Cancer Cell Growth by SiRNA Cocktails and 5-Fluorouracil Using Effective Piperidine-Terminated Phosphorus Dendrimers
Colloid. Interface. 2018, 1(1), 6; doi:10.3390/colloids1010006
Received: 9 October 2017 / Revised: 27 October 2017 / Accepted: 10 November 2017 / Published: 13 November 2017
PDF Full-text (3575 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Currently, RNAi based approaches for cancer treatment involving short double stranded RNA molecules (siRNA) are under vigorous scrutinization. Due to numerous biological obstacles, siRNA delivery into target cells requires protective escort. On the other hand, combining of siRNA-mediated gene silencing and action of
[...] Read more.
Currently, RNAi based approaches for cancer treatment involving short double stranded RNA molecules (siRNA) are under vigorous scrutinization. Due to numerous biological obstacles, siRNA delivery into target cells requires protective escort. On the other hand, combining of siRNA-mediated gene silencing and action of conventional chemotherapeutics can propose additional enhancement of anticancer activity. In the present study, we investigated a siRNA cocktail able to downregulate anti-apoptotic genes (BCL-xL, BCL-2, MCL-1) and the chemotherapeutic agent 5-fluorouracil (5-FU) to evaluate multi-target cytotoxic effect on human cervical carcinoma cells (HeLa cell line). Novel phosphorus containing dendrimers of 3rd and 4th generations (namely AE2G3 and AE2G4) with voluminous piperidine terminal cationic groups were designed and tested as siRNA carriers. Dendrimers of both generations showed remarkable ability to bind pro-apoptotic siRNAs and provided 80–100% siRNA uptake by HeLa cells in the serum containing medium, while the widespread transfection agent Lipofectamine showed only ~40% uptake. SiRNA cocktail (in low concentrations 50 and 100 nM) delivered by AE2G3 dendrimer caused almost complete elimination of cancer cells. We have discovered considerable increase of 5-FU cytotoxic effect by addition of AE2G3/siRNA cocktail complexes in low doses. Thus, we demonstrated the effectiveness of combined multi-target siRNA anticancer approach and described new highly effective serum stable nanomaterial vehicle for gene-based drugs. Full article
Figures

Open AccessArticle Synthesis and Characterization of Hybrid Particles Obtained in a One-Pot Process through Simultaneous Sol-Gel Reaction of (3-Mercaptopropyl)trimethoxysilane and Emulsion Polymerization of Styrene
Colloid. Interface. 2018, 1(1), 7; doi:10.3390/colloids1010007
Received: 27 October 2017 / Revised: 10 November 2017 / Accepted: 14 November 2017 / Published: 16 November 2017
PDF Full-text (1738 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Hybrid particles consisting of an organic polymer and silica or polyorganosiloxanes are interesting building blocks for nanocomposites. The synthesis of such particles typically requires multiple reaction steps involving the formation of polymer colloids and the subsequent deposition of silicon-containing material either inside or
[...] Read more.
Hybrid particles consisting of an organic polymer and silica or polyorganosiloxanes are interesting building blocks for nanocomposites. The synthesis of such particles typically requires multiple reaction steps involving the formation of polymer colloids and the subsequent deposition of silicon-containing material either inside or on the surface of these colloids, or vice versa. In 2014, we reported a facile method for the one-pot synthesis of sub-micron sized hybrid particles based on simultaneous sol-gel conversion of organotrimethoxysilanes and emulsion polymerization of a vinylic monomer, illustrated by the synthesis of polystyrene-polyphenylsiloxane particles from the monomers styrene and phenyltrimethoxysilane (Segers et al (2014). In this process, the required surface active species was formed in situ through hydrolytic conversion of phenyltrimethoxysilane to phenylsilanolate oligomers. Introduction of thiol groups in such hybrid particles should yield particles suited for functionalization with small metal nanoparticles, e.g., Au. Here, we present the synthesis of thiol-containing hybrid particles consisting of poly(3-mercaptopropyl)siloxane and polystyrene using the one-pot synthesis method based on simultaneous conversion of (3-mercaptopropyl)trimethoxysilane and styrene. We prepared particles from different volume ratios of (3-mercaptopropyl)trimethoxysilane and styrene, ranging from 1:99 to 80:20. The resulting spherical hybrid particles displayed different sizes, compositions, and architectures (including core-shell), which were studied in detail using scanning electron microscopy, thermogravimetric analysis, and scanning transmission electron microscopy combined with energy dispersive x-ray spectroscopy. The composition of these particles, and consequently the number of thiol groups available for further functionalization such as metal anchoring, was tunable. Full article
Figures

Figure 1

Review

Jump to: Research

Open AccessReview The Use of Polymer and Surfactants for the Microencapsulation and Emulsion Stabilization
Colloid. Interface. 2018, 1(1), 3; doi:10.3390/colloids1010003
Received: 19 September 2017 / Revised: 13 October 2017 / Accepted: 18 October 2017 / Published: 29 October 2017
PDF Full-text (2196 KB) | HTML Full-text | XML Full-text
Abstract
Polymer/surfactant mixtures have a wide range of industrial and technological applications, one of them being the use in microencapsulation and emulsion stabilization processes. These mixtures are able to form adsorption layers at the surface of oil droplets and so affect the emulsion stability,
[...] Read more.
Polymer/surfactant mixtures have a wide range of industrial and technological applications, one of them being the use in microencapsulation and emulsion stabilization processes. These mixtures are able to form adsorption layers at the surface of oil droplets and so affect the emulsion stability, which depends on the polyelectrolyte/surfactant nature, concentrations ratio, method of the emulsification, etc. Polyelectrolytes alone show low surface activity in contrast to surfactants, which adsorb at the water/oil interface, making the droplets charged, but they are insufficient to stabilize emulsions. When an oppositely-charged polymer is added to the surfactant solution, a steric barrier is formed, which prevents coalescence and enhances the stability. The present review is devoted to the recent studies of the use of polymer/surfactant mixtures for the encapsulation of active ingredients and stabilization of single and double emulsions. Active ingredients are added to the oil phase prior to emulsification so that any subsequent dissolution of the core, like in other encapsulation protocols, can be omitted. By measuring the interfacial tension and dilational rheology it is possible to find optimum conditions for the emulsion formation and hence for encapsulation. Therefore, such systems have become a prominent approach for the encapsulation of active ingredients. Full article
(This article belongs to the Special Issue Selected Papers from Bubble & Drop 2017)
Figures

Open AccessReview Recent Applications of Ionic Liquids in the Sol-Gel Process for Polymer–Silica Nanocomposites with Ionic Interfaces
Colloid. Interface. 2018, 1(1), 5; doi:10.3390/colloids1010005
Received: 21 October 2017 / Revised: 3 November 2017 / Accepted: 5 November 2017 / Published: 10 November 2017
PDF Full-text (10221 KB) | HTML Full-text | XML Full-text
Abstract
Understanding the organic–inorganic interphases of hybrid materials allows structure and properties control for obtaining new advanced materials. Lately, the use of ionic liquids (ILs) and poly(ionic liquids) (PILs) allowed structure control from the first sol-gel reaction steps due to their anisotropy and multiple
[...] Read more.
Understanding the organic–inorganic interphases of hybrid materials allows structure and properties control for obtaining new advanced materials. Lately, the use of ionic liquids (ILs) and poly(ionic liquids) (PILs) allowed structure control from the first sol-gel reaction steps due to their anisotropy and multiple bonding capacity. They also act as multifunctional compatibilizing agents that affect the interfacial interactions in a molecular structure-dependent manner. Thus, this review will explore the concepts and latest efforts to control silica morphology using processes such as the sol-gel, both in situ and ex situ of polymer matrices, pre-polymers or polymer precursors. It discusses how to control the polymer–filler interphase bonding, highlighting the last achievements in the interphase ionicity control and, consequently, how these affect the final nanocomposites providing materials with barrier, shape–memory and self-healing properties. Full article
Figures

Figure 1

Back to Top