Solid Surfactant Research Articles

Preparation, Characterization, and Molecular Dynamic Simulation of Novel Coenzyme Q10 Loaded Nanostructured Lipid Carriers.

Research proved that coenzyme Q10-loaded NLC effectively removes skin wrinkles, therefore, such a formulation with good characteristics is still the research goal. This study investigated the effect of solid lipids and surfactant type on the physical characteristics of Q10-NLC. We aimed to achieve the optimum formulation for producing NLC with long-term stability and high Entrapment efficiency (E.E.) %. We compared the experimental results with the output of the Molecular dynamic (M.D.) simulations. To develop Q10-NLC, various solid lipids, MCT oil, and surfactants were employed. The formulations were prepared by high-shear homogenization and ultrasound methods. Stability studies were carried out 1,3, and 6 months at 4, 25, and 40°C. The optimized NLC formulations were characterized by photon correlation spectroscopy (PCS), Transmission electron microscopy (TEM), Differential scanning calorimetry (DSC), and Fourier transform infrared (FT-IR). E.E. % was determined by HPLC analysis. Atomistic M.D. simulations of two model systems were performed to gain insights into the self-assembled process of co-Q10 with other formulation components. Statistical analysis (Two-way ANOVA) revealed that solid lipid and surfactant factors had a significant influence on particle size, PDI, and zeta potential (***p < 0.0001). According to the results, F1 and F6 formulations had desirable surface characterizations, physicochemical stability, and high E.E. %. The atomistic M.D. simulations confirmed that the F1 system (best) was more stable than the F31 system (worst). The solid lipids: tripalmitin and compritol, stabilized with 4% tween 80 and 1% span 80, have produced stable NLC with the best surface characteristics that could be a promising formulation for the delivery of Q10. Atomistic M.D. simulation has confirmed the stability of F1 in comparison to F31.

Statistically Optimized Tacrolimus and Thymoquinone Co-Loaded Nanostructured Lipid Carriers Gel for Improved Topical Treatment of Psoriasis.

The aim of this investigation was to develop and analyze a tacrolimus and thymoquinone co-loaded nanostructured lipid carriers (TAC-THQ-NLCs)-based nanogel as a new combinatorial approach for the treatment of psoriasis. The NLCs were formulated by an emulsification-solvent-evaporation technique using glyceryl monostearate, Capryol 90 (oil), and a mixture of Tween 80 and Span 20 as a solid lipid, liquid lipid, and surfactant, respectively. Their combination was optimized using a three-factor and three-level Box-Behnken design (33-BBD). The optimized TAC-THQ-NLCs were observed to be smooth and spherical with a particle size of 144.95 ± 2.80 nm, a polydispersity index of 0.160 ± 0.021, a zeta potential of -29.47 ± 1.9 mV, and an entrapment efficiency of >70% for both drugs. DSC and PXRD studies demonstrated the amorphous state of TAC and THQ in the lipid matrix of the NLCs. An FTIR analysis demonstrated the excellent compatibility of the drugs with the excipients without interactions. The TAC-THQ-NLC-based nanogel (abbreviated as TAC-THQ-NG) exhibited a good texture profile and good spreadability. The in vitro release study demonstrated a sustained drug release for 24 h from the TAC-THQ-NG that followed the Korsmeyer-Peppas kinetic model with a Fickian diffusion mechanism. Moreover, the TAC-THQ-NG revealed significantly higher dose-dependent toxicity against an HaCaT cell line compared to a TAC-THQ suspension gel (abbreviated as TAC-THQ-SG). Furthermore, the developed formulations demonstrated antioxidant activity comparable to free THQ. Confocal microscopy revealed improved permeation depth of the dye-loaded nanogel in the skin compared to the suspension gel. Based on these findings, it was concluded that TAC-THQ-NG is a promising combinatorial treatment approach for psoriasis.

Effect of Solvent Polarity on Fabrication of Dual Janus Particles with Asymmetric Morphology and Chemical Identity via Photo-initiated Seeded Swelling Polymerization

Particles with asymmetric morphology or surface chemical identity (Janus) are of great interest in the field of materials due to their special composition and structure. However, it is still a challenge to prepare particles with dual asymmetry via simple and convenient synthesis strategies. Herein, micron-sized dual-asymmetry Janus particles were prepared via photo-induced seeded swelling polymerization within 30 min. By controlling the polarity of the organic solvent (porogenic reagent), Janus particles with various morphologies were fabricated. The particles with convex surfaces, such as dumbbell-shaped, snowman-shaped, and golf-shaped morphologies, were obtained in the polar porogenic system, while the concave surface particles, such as bowl-shaped and ball-in-bowl, were acquired in the non-polar porogenic system. Mushroom-shaped and pinecone-shaped particles were generated in the binary porogenic system. Particularly, snowman-shaped, bowl-shaped, and pinecone-shaped particles were characterized by confocal laser scanning microscopy, exhibiting asymmetric chemical identity. They could be easily modified into amphiphilic solid surfactants for emulsifying oil–water incompatible mixtures with a definite interfacial orientation. This strategy provides a possibility for the simple and rapid preparation of dual Janus particles with asymmetric morphology and chemical identity, which are expected to be produced on a large scale.

SOLID LIPID NANOPARTICLES OF GABAPENTIN FOR PARTIAL SEIZURES

The goal of this research was to create a stable formulation of gabapentin solid lipid nanoparticles which would allow it to pass across the blood-brain barrier more easily. They were prepared by solvent evaporation method. In the present investigation, beeswax and carnauba wax were used as solid lipids, egg lecithin was used as a surfactant and Tween 80 was used as a co-surfactant. Nine formulations were formulated using different concentrations of solid lipid and surfactant. The prepared formulations were evaluated for various tests. The results shown that F6 formulation, containing higher concentration of egg lecithin, was a better formulation as percentage drug content was 97.57±0.62%, entrapment efficiency was 95.95±0.07% and in vitro release of gabapentin was 97.18±1.02% at the end of 12 h. After in vivo testing, it was observed that animals treated with gabapentin loaded solid lipid nanoparticles had seizures that appeared later than animals treated with traditional gabapentin formulations. Hence it was concluded that solid lipid nanoparticles is a promising drug delivery system to achieve increased permeability through blood brain barrier.

Simultaneous estimation of neratinib and naringenin from pharmaceuticals using a stability-indicating liquid chromatographic method: Application to analytical quality by design concept and multi-tool method greenness assessment

A validated stability-indicating simultaneous liquid chromatographic method was developed to estimate neratinib (NRB) and naringenin (NRN). We used the principles of analytical quality by design (AQbD) to develop a robust analytical method. The ACN%, pH, and flow rate were the three method variables investigated and optimized using the Box-Behnken experimental design (BBD). The optimized chromatographic condition used a mobile phase of ACN: phosphate buffer pH 3.8 (70:30 v/v) flowing at 0.6 mL.min−1 on a 250 mm C-18 column. Diode array detection was performed at 277 nm. The method was robust, linear (r2 = 0.999), accurate and precise. The detection and quantitation limits were 0.275 and 1.0 µg.mL−1 for both drugs. Forced degradation revealed non-interference of degradation peaks with the analyte peaks and ensured method specificity. The LC estimation demonstrated higher solubility of NRB and NRN in Precirol ATO5 and Tween 80 as solid lipid and surfactant, respectively. In addition, the entrapment efficiencies were 78 % and 86 % for SLNs of NRB and NRN, respectively. After 24 h, the In-vitro release study indicated that 40 % of the drugs were released from the pure drug suspension and >95 % released from the SLN. Afterwards, the results from five different greenness assessment approach established the present method's green nature. Overall, a green, federally robust, and flexible liquid chromatographic method was developed and can be applied routinely to estimate NRB and NRN from the developed nano formulation.

Development of solid lipid nanoparticle gel for transdermal delivery system of chaulmoogra oil

Aim: The main objective of the study was to formulate, evaluate and perform an optimization study of chaulmoogra oil-loaded solid lipid nanoparticles (SLNs) based gel. Methods: The study involves isolation, identification, and quantification of hydnocarpic acid (HA), using high-performance thin-layer chromatography (HPTLC) and characterization using ultraviolet (UV), nuclear magnetic resonance (NMR), and mass spectroscopy (MS), and differential scanning calorimetry (DSC). Different concentration of assorted solid lipids and surfactants was used for the preparation of SLN gel with the improved transdermal application. Size distribution, entrapping efficiency, transmission electron microscopy (TEM), and percent yield were tested for the prepared SLN and the characterization of SLN gel was evaluated on the basis of in vitro diffusion study, stability studies, homogeneity, and skin irritancy test. Results: The amount of HA quantified in the oil sample was found to be 54.84% w/w. The percent yield and entrapment efficiency (EE) of HA SLNs were 96.176 ± 1.338% and 90.2 ± 0.5% respectively. The in vitro percent cumulative drug release was 80.89% for the developed SLN, the homogeneity test showed no grittiness, and the prepared gel was found to be effective as it shows no signs of erythema post-treatment of 10 days. The in vitro dissolution studies showed better results for SLN gel when compared to SLN suspension. Conclusions: The nano-gel could be a better option for the topical delivery of herbal drugs with improved bioavailability providing several benefits over conventional formulation.

Fabrication of Partially Etched Polystyrene Nanoparticles.

Non-spherical polymer nanoparticles (NPs) have gained attention in various fields, but their fabrication remains challenging. In this study, we present a simple protocol for synthesizing partially etched polystyrene (PS) nanoparticles through emulsion polymerization and chemical etching. By adjusting the degree of crosslinking, we selectively dissolve the weakly crosslinked portions of the particles, resulting in partially etched PS NPs with increased surface area. These partially etched NPs are evaluated for their use as solid surfactants in Pickering emulsions, where they demonstrate significantly improved emulsion stability compared to intact spherical NPs. Our results contribute to the field of nanoparticle shape control and provide insights into developing novel materials for various applications, particularly in the area of solid surfactant usage. Additionally, the importance of conducting cellular toxicity studies using these partially etched NPs for future work is also emphasized.

Molecular dynamics and thermo physical properties of solid catanionic surfactants composed of octadecyltrimethylammonium bromide and n-alkanoic acids

Two mixed surfactants comprising cationic octadecyltrimethylammonium bromide CH3(CH2)17N+(CH3)3Br− (C18TAB) modified with dodecanoic C12H24O2 (DDA) or hexadecanoic C16H32O2 (HDA) acids have been studied in the solid state in a wide temperature range (25–150 °C). The molecular dynamics and thermotropic properties of acid-modified asymmetric DDA-C18TAB and symmetric HDA-C18TAB surfactants were investigated using DSC measurements and temperature-variable FTIR spectroscopy complemented by room-temperature powder X-ray diffraction. XRD showed a formation of a new layered compound, the acid-modified C18TAB mixed surfactant comprising a hydrophobic moiety formed by two alkyl chains of different lengths. DSC measurements revealed the difference in thermal behavior between symmetric and asymmetric mixed surfactants showing successive phase transitions and several polymorphs in the solid state. With FT-IR spectroscopy, the phase transitions seen in DSC were identified as related to subtle lattice rearrangements in the low-temperature phases C1C2, the trans-gauche conformational disorder and rotational motions of methylene chains followed with lattice instabilities in the intermediate phases C3 and C4, and finally rotational disorder of the alkyl chains and the ionic layer in the high temperature phase H. For the first time, the stabilization effect of DDA acid on the bilayer structure of C18TAB was found.

Enhancement of in-vitro anti-oral cancer activities of silymarin using dispersion of nanostructured lipid carrier in mucoadhesive in-situ gel

Silymarin (SME) shows multiple therapeutic actions against several cancers, however, low aqueous solubility and poor bioavailability issues restrict its clinical use. In this study, SME was loaded in nanostructured lipid carriers (NLCs) and further incorporated in mucoadhesive in-situ gel (SME-NLCs-Plx/CP-ISG) for localized treatment of oral cancer. Using a 33 Box-Behnken design (BBD), an optimized SME-NLC formula was developed with the ratios of solid lipids, surfactant concentration, and sonication time as independent variables, while particle size (PS), polydispersity index (PDI), and % encapsulation efficiency (EE) as dependent variables, resulting in 315.5 ± 0.1 nm PS, 0.341 ± 0.01 PDI, and 71.05 ± 0.05 % EE. Structural studies confirmed the formation of SME-NLCs. SME-NLCs incorporated in-situ gel demonstrated a sustained release for SME, indicating enhanced retention on the buccal mucosal membrane. The in-situ gel containing SME-NLCs showed a marked decrease in IC50 value (24.90 ± 0.45 µM) than SME-NLCs (28.40 ± 0.89 µM) and plain SME (36.60 ± 0.26 µM). The studies demonstrated that Reactive oxygen species (ROS) generation potential and SME-NLCs-Plx/CP-ISG induced apoptosis at Sub-G0 phase owing to higher penetration of SME-NLCs led to higher inhibition against human KB oral cancer cells. Therefore, SME-NLCs-Plx/CP-ISG can be the alternative to chemotherapy and surgery with site-specific delivery of SME to oral cancer patients.

Ultrafine quartz flocculation: Part II. Main variables

Flocculation is a complex process, usually dependant on various conditions to perform adequately. Nevertheless, the relevance and interaction of the process variables are not easily found in literature. In this study, nine variables of ultrafine quartz flocculation systems, defined in Part 1 of this study, were analysed. The effects of each variable and their interactions in the system were investigated based on flocculation and sedimentation tests. The results were statistically evaluated using the supernatant turbidity as experimental response. The evaluations resulting from the statistical approach indicated that suspension pH (5.49%) was the most significant variable, followed by flocculant concentration (4.07%) with the second greatest effect on the turbidity of the supernatant. Solid concentration, agitation intensity, and surfactant conditioning time (4.05%, 3.51% and 3.51%, respectively), also have significant effects on ultrafine quartz flocculation. The flocculant concentration and the surfactant conditioning time were the variables with the most significant interactions with the main variables. The Camp Number values showed a negative exponential relationship with the turbidity results, proving to be an important tool to evaluate flocculation. Backscattered electron scanning microscopy images of flocs formed in the presence of 30 g/t PAM showed compact flocs in the size range between 150 and 365 µm, with noticeable sphericity.

Nanostructured Lipid Carriers of Eperisone Hydrochloride using Quality By Design Approach

Objective: The current work involves formulation development of nanostructured lipid carrier (NLC) of eperisone hydrochloride (EPE) using quality by design (QbD) approach.&#x0D; Materials and Methods: Initial screening of solid and liquid lipids was performed based on the Hansen solubility parameters of EPE and the lipids and later confirmed using saturation solubility studies. The optimum formulation was identified using three-squared randomized full factorial design. High shear homogenization coupled with ultrasonication was used to prepare the NLCs. The effect of the independent variables on the dependent variables was analyzed using response surface graphs and ANOVA. The optimized formulation is characterized for mean particle size, zeta potential, entrapment efficiency, in vitro drug release and subjected to stability testing.&#x0D; Results and Discussion: Precirol® ATO 5, CapryolTM 90, and Pluronic® F127 are found to be ideal solid lipid, liquid lipid and surfactant respectively based on the initial screening. Amount of lipid mixture (X1) and the amount of surfactant (X2) were selected as independent variables and the entrapment efficiency (Y1), mean particle size (Y2) and zeta potential (Y3) were selected as dependent variables. The optimized NLC formulation has mean particle size of 175 nm, zeta potential -24.4 mV and entrapment efficiency of 78.64%. The in vitro drug release data suggested that the drug release follows Quasi-Fickian diffusion. The stability data showed that the NLCs are stable up to 3 months at refrigerated conditions.&#x0D; Conclusions: The Hansen solubility parameter approach coupled with QbD is a powerful tool for formulation of sustained release NLCs of highly soluble poorly soluble drugs.&#x0D; Keywords: Nanostructured lipid carrier, Solubility Parameters, Nanoparticles, Lipid based drug delivery, Quality by Design

Development and evaluation of the effectiveness of a solid shampoo bar

Solid shampoo is an innovative and alternative cosmetic form of shampoo that, as it does not contain water in its composition, gains the attribute of being more sustainable. This work aims to develop, evaluate the stability, and characterize a solid shampoo formulation. Nine solid shampoo formulations were prepared by varying the concentrations of solid surfactants defined through a statistical design. The formulations, labeled F1 to F9, were submitted to the preliminary stability evaluation under different storage conditions for 30 days, in which organoleptic characteristics as well as the pH values were evaluated. Approved formulations were physically and functionally characterized. Only two formulations (F3 and F5) were approved in the stability assessment because they did not show changes in consistency, color, odor, appearance, and pH under different storage conditions. These formulations showed stable foaming, but crumbled very easily and presented low hardness, which indicates the need to adjust the concentration of consistency agents to make the formulation more resistant to breakage. The formulations demonstrated excellent cleaning and conditioning ability.

Pioglitazone-loaded nanostructured lipid carriers: In-vitro and in-vivo evaluation for improved bioavailability

Pioglitazone (PZ), a highly lipophilic Class II drug with poor aqueous solubility possesses low oral bioavailability. The oral bioavailability of pioglitazone can be improved by incorporating into nanostructured lipid carriers (NLCs). Pioglitazone-loaded nanostructured lipid carriers (PZ-loaded NLCs) were developed by using the solvent emulsification evaporation method. The lipid phase of the formulation consists of a solid and liquid lipid mixture (fatty acids and oils) and surfactants (Tween 20, Span 40) were used for the stability of the formulation. PZ-loaded NLCs were characterized for physicochemical characteristics including particle size, zeta potential, polydispersity index (PDI), fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) and stability studies. Moreover, drug entrapment efficiency, drug loading capacity, drug release, toxicity studies, permeation studies, and in-vivo studies were performed to evaluate enhanced bioavailability. PZ-loaded NLCs have shown an average particle size of 152 nm, PDI of 0.19, and a negative value of zeta potential. Drug entrapment efficiency and loading capacity were about 83% and 5.8%, respectively. SEM results delineated the smooth homogenous surface in nano-sized range, whereas FTIR spectra demonstrated no interaction between components of PZ-loaded NLCs formulation. For drug release studies, the dialysis bag method confirmed a biphasic release behavior in beginning followed by slow, controlled release up to 24 h. Furthermore, permeation studies showed enhanced permeability and in-vivo studies confirmed the enhanced bioavailability of pioglitazone. Based on the above finding, it can be concluded that NLCs are a versatile tools for enhancing the bioavailability of poorly soluble Class II drugs.

NANOSTRUCTURED LIPID CARRIERS: A NOVEL STRATEGY FOR TRANSDERMAL DRUG DELIVERY SYSTEMS

Drug administration via the skin is one of the most conventionally used methods where the flux through the skin is the rate-limiting step. Safe carriers are used to provide the anticipated therapeutic effects, which play a vital role in drug delivery. A nanostructured lipid carrier (NLC) is a binary mixture of solid and liquid lipids and surfactants. The lipid nature and nano size of these carriers contribute to the skin penetration of therapeutic agents. These carriers have a wide variety of advantages, such as good biocompatibility, low cytotoxicity, high drug quality and increased stability. This paper deliberates the suitability of NLCs in transdermal drug delivery, their properties, the methods of preparation and their applications.

Augmented Oral Bioavailability and Prokinetic Activity of Levosulpiride Delivered in Nanostructured Lipid Carriers.

The present study is aimed to develop and optimize levosulpiride-loaded nanostructured lipid carriers (LSP-NLCs) for improving oral bioavailability and prokinetic activity of LSP. LSP-NLCs were optimized with D-optimal mixture design using solid lipid, liquid lipid and surfactant concentrations as independent variables. The prepared LSP-NLCs were evaluated for physicochemical properties and solid-state characterization. The in vivo oral pharmacokinetics and prokinetic activity of LSP-NLCs were evaluated in rats. LSP-NLCs formulation was optimized at Precirol® ATO 5/Labrasol (80.55/19.45%, w/w) and Tween 80/Span 80 concentration of 5% (w/w) as a surfactant mixture. LSP-NLCs showed a spherical shape with a particle size of 152 nm, a polydispersity index of 0.230 and an entrapment efficiency of 88%. The DSC and PXRD analysis revealed conversion of crystalline LSP to amorphous state after loading into the lipid matrix. LSP-NLCs displayed a 3.42- and 4.38-flods increase in AUC and Cmax after oral administration compared to LSP dispersion. In addition, LSP-NLCs showed enhanced gastric emptying (61.4%), intestinal transit (63.0%), and fecal count (68.8) compared to LSP dispersion (39.7%, 38.0% and 51.0, respectively). Taken together, these results show improved oral bioavailability and prokinetic activity of LSP-NLCs and presents a promising strategy to improve therapeutic activity of LSP for efficient treatment of gastric diseases.

Engineered reversible adhesive biofoams for accelerated dermal wound healing: Intriguing multi-covalent phenylboronic acid/cis-diol interaction

Development of wound dressings that not only have multiple advantages including good biocompatibility, barrier properties, adhesive properties, but also exhibit anti-bacterial, anti-infection, and promote cell adhesion, accelerated wound healing process, remains challenging in the skin tissue engineering. In this work, a noninvasive adhesive biofoam with interconnectivity structure and antibacterial property was first-time designed through solid surfactant stabilized high internal phase emulsion (HIPE) template, where bacteriostatic Zn-CuO@GO nanosheets dynamic assemble with 4-vinylphenylboronic acid at the oil/water interface as cooperative emulsifier. Taking advantage of the cooperative assembly of the PBA/Zn-CuO@GO, the biofoams display microfibrousity and interconnectivity to facilitate material-cellular interaction as well nutrient exchange, and can effectively inhibit the growth of E. coli and S. aureus. Meanwhile, phenylboronic acid functional groups not only endow biofoam reversible adhesive property though dynamic phenylboronic acid/cis-diol interaction, but also facilitate the rearrangement of Zn-CuO@GO nanosheets in more uniform way at emulsion interface. Taken together, the biofoams can strongly adhere to the wound bed reducing the risk of infection and accelerate earlier tissue regeneration, which exhibit great potential in bioengineering application.

Colloidosome-templated poly (L-lactic acid) crystalsomes

Polymers have been utilized to direct nanoparticle (NP) assembly into complex shapes and morphologies. Strategies for polymer-directed NP assembly often involve tuning the phase behavior of multi-component polymer/nanoparticle systems. In this work, we report the co-assembly of polymer and NPs into hollow vesicles using confined polymer crystallization-directed assembly. 5 nm and 20 nm Fe3O4 NPs are used as the solid surfactants to create Pickering emulsions of water and poly(L-lactic acid) (PLLA) toluene solution. The oil/water interface of the emulsion droplets templates the growth of PLLA crystals, which in turn, immobilize NPs onto the crystal surface, leading to the formation of colloido-polymer-crystalsomes (CPCs). The structure, morphology, and formation mechanism of the CPCs are investigated using electron microscopy and thermal analysis techniques. This work provides a new approach to fabricate nanoscale complex NP-polymer conjugates.

Nanostructured Lipid Carriers: New Insight for Cancer Therapy

Abstract: Cancer is a life-threatening disease that is associated with persistent tissue injury and uncontrolled cell growth. The treatments available to treat cancer include chemotherapy, surgery, and radiation therapy. These treatments are utilized in combination while the most preferred treatment is chemotherapy. Because of the non-specificity of anticancer drugs, they kill healthy cells along with cancer cells, which lead to severe side effects. To minimize such limitations associated with conventional chemotherapy, nanostructured lipids carriers (NLCs) can be developed. These are the nanocarriers consisting of a mixture of solid and liquid lipids and surfactants. Lipids utilized in the formulation of NLCs are biocompatible and biodegradable. NLCs ensure high drug payload, less drug expulsion, and more stability on storage. NLCs enhance the aqueous solubility of lipophilic anticancer drugs. Their surface modification can help to overcome drug resistance in cancer therapy. Controlled and targeted drug delivery of anticancer drugs can be possible by formulating them as NLCs. NLCs can play an important role in targeting anticancer drugs by different mechanisms. This review highlights types, formulation methods, characterization of nanostructured lipid carriers, and strategies to achieve targeted release of anticancer drugs loaded in NLCs.

On-the-Fly Formation of Polymer Film at Water Surface.

The self-propulsion of bodies floating in water is of great interest for developing new robotic and intelligent systems at different scales, and whenever possible, Marangoni propulsion is an attractive candidate for the locomotion of untethered micro-robots. Significant cases have been shown using liquid and solid surfactants that allow an effective propulsion for bodies floating on water to be achieved. Here, we show for the first time a strategy for activating a twofold functionality where the self-propulsion of a floating body is combined with the formation of a polymer thin film at the water surface. In fact, we demonstrate that by using polymer droplets with an appropriate concentration of solvent and delivering such drops at specific locations onto freely floating objects, it is possible to form “on-the-fly” thin polymer films at the free water surface. By exploiting self-propulsion, a polymer thin film can be formed that could cover quite extensive areas with different shapes depending on the motion of the floating object. This intriguing twice-functionality activated though a single phenomenon, i.e., film formation and related locomotion, could be used in perspective to perform complex operations at water surfaces, such as dynamic liquid packaging, cleaning, and moving away floating particles, monolayer films, or macro-sized objects, as discussed in the text.

An organic-based amphiphilic Janus polymer nanosheet: Synthesis, properties, and microscopic dispersion interpretations

Due to the distinctive anisotropy in shapes and affluent potential in properties, amphiphilic Janus polymer nanosheets (AJPN) have attracted widespread attention. Low-cost, controllable, and precise functional polymerization remains a great challenge to conventional template methods. Herein, an organic-based AJPN was synthesized with polystyrene as the hydrophobic side and carboxyl groups presented at the hydrophilic side. Sucrose was selected as the adsorption template, which could be removed simply by water-washing. The lateral sizes could be regulated by adjusting the ultrasonic time and power after the precise construction of polymer shells. The colloidal stability and aggregation kinetics of AJPN suspension under different conditions were quantitatively measured. In particular, Rheolaser optical microrheology was pioneered to explore the authentic migration behaviors and rheological properties of AJPN aqueous solution for the first time. The results revealed that AJPN solution presented as thermodynamically unstable solid suspension, which was far different from real solution, emulsion or cross-linked hydrogel formed by common hydrophilic polymers. The carboxyl groups and the steric effect of polymer chains greatly improved the self-stability of AJPN suspension. The influences of microscopic migration of AJPN on their macroscopic dispersion in different stages were concluded, which was closely related to the applicability of nanofluid products in storage, transportation, or performance periods. Moreover, due to the amphiphilic property, Janus nature and lamellar nanomorphology, AJPN could be used as solid surfactants to reduce oil–water interfacial tension and stabilize emulsions. We hope this work can offer more opportunities for the synthesis of AJPN with different chemical compositions, and promote the development of dispersion stability of nanosheets.