Aqueous Solutions Of Polyethylene Glycol Research Articles

New Autonomous Water-Enabled Self-Healing Coating Material with Antibacterial-Agent-Releasing Properties.

A new autonomous water-enabled self-healing coating with antibacterial-agent-releasing capability was developed for the first time by precipitating an aqueous solution of hydrogen-bonded tannic acid (TA) and polyethylene glycol (PEG) (TA: 5 mg/mL; PEG: 5 mg/mL with MW = 100 kDa) to form a smooth, uniform coating layer with an average roughness of 0.688 nm and thickness of 22.3 μm on a polymethyl methacrylate (PMMA) substrate after 10 min of incubation. Our method is cost- and time-efficient, as the hydrophilic coating (water contact angle = 65.1°) forms rapidly, binding strongly to the PMMA substrate (adhesive energy = 83 mJ/m2), without the need for pretreatment or surface modification, and is capable of rapid self-repair (approximately 5 min) through hydrogen bonding in aqueous media. Furthermore, adding 0.5 mg/mL of chlorhexidine acetate (CHX), a commonly used antibacterial agent in dentistry, into the TA–PEG emulsion allowed the release of 2.89 μg/mL of the drug from the coating layer, which is promising for actively inhibiting the vitality and growth of bacteria around PMMA dental restorations. The use of CHX-loaded TA–PEG hydrogen-bonded complexes is highly favorable for the fabrication of an autonomous self-healing biocoating with active antibacterial-agent-releasing capability, which can be applied not only in dentistry but also in other medical fields.

Structure and Intermolecular Interactions in Aqueous Solutions of Polyethylene Glycol.

Aqueous solutions of polyethylene glycol are studied by small-angle neutron scattering over a broad range of polymer molecular masses and concentrations. The scattering data were modeled by a Gaussian chain form factor combined with random phase approximation, which provided good fits over the whole studied concentration range. The results showed that polyethylene glycol in the molecular mass range –20 kDa in water at physiological temperature T = 37 C behaves like a random coil in nearly theta solvent conditions. The obtained results serve as a reference for the description of complex mixtures with PEG used in various applications.

Characterization of hydrogen bond network of waters around polyethylene glycol by broadband dielectric spectroscopy

Polyethylene glycol (PEG) is a well-known water retention agent in biomedical products, the hydration efficiency of which is affected by its molecular weight. Using a broadband dielectric spectroscopy (100 MHz–18 THz), the hydration state of PEG aqueous solutions with various molecular weights was quantitatively evaluated. As the molecular weight increases, the restriction strength of hydration water increases in potency, while the number of hydration water molecules decreases. Owing to the opposite changes in hydration number and restriction strength, the measured collective hydrogen bond (HB) strength shows negligible molecular weight dependence. PEG with larger Mw produces a more heterogenous HB network. The internal folding and twining caused by the growth of the PEG chain obstruct the proper exposure of hydrophilic part of the monomer producing less hydration waters. The evaluation result supports an application of PEGs with low molecular weight in contact lens package solutions.

Ultrasonic and Volumetric Studies of Aqueous Solution of Polyethylene Glycol

In present study an attempt has been made to analyse the molecular interactions of aqueous solution of polyethylene glycol of molecular weight 200 at different concentration and at different temperature by determining density, viscosity, and ultrasonic velocity. Various parameters like, adiabatic compressibility acoustic impedance and intermolecular free length have been calculated at different temperatures and at 0.50% concentration. This study helps to understand the physio-chemical behavior of macro molecules with change in temperature and concentration.

Studies of intrinsic volumes of ethylene glycol and polyethylene glycol–300 molecules in aqueous solutions at 298.15 K: Application of Tammann–Tait–Gibson (TTG) equation of state

Systemic density (ρ) measurements have been carried–out for aqueous solutions of polyethylene glycols (PEG's) with the molar mass 200, 300, 400 and 600 D at (288.15, 293.15, 298.15, 303.15 and 308.15) K and at ambient pressure of 0.1 MPa in dilute solute concentration region (0.0119–0.4941 mol⋅kg−1). The ρ data are used to obtain the apparent molar volume (Vϕ) and partial molar volume (V¯2) of studied PEG's in aqueous solutions at finite concentration as well as at infinitely dilute solutions (Vϕ0) at studied temperatures. The coefficient of thermal expansion (α) for solutions, apparent molar expansivity (Eϕ) and limiting apparent molar expansivity (Eϕ0) for solutes are calculated at 293.15, 298.15 and 303.15 K. The densities of studied PEG's in carbon tetrachloride (CCl4) medium are also measured at 298.15 K. The transfer volume (ΔtrVϕ0) for PEG from pure liquid state to CCl4 and to water as solvent are estimated. The literature data of sound velocity (u), coefficient of thermal expansion (α) and specific heat capacity (CP) for solutions have been utilized to obtain thermodynamic properties like adiabatic compressibility (βad) and isothermal compressibility (βT) in case of aqueous solutions of ethylene glycol (EG) and PEG–300 at 298.15 K. The data are further utilized to obtain apparent molar adiabatic compressibility (KϕS) and apparent molar isothermal compressibility (KϕT) for EG and PEG–300 solute molecules at finite and at infinitely dilute solute concentration (KϕS0 and KϕT0, respectively). Further, the data of KϕT, α and CP data have been utilized to estimate internal pressure Pi (=∂U∂VT) of solutions containing EG and PEG–300 molecules as a function of concentration. The intrinsic volumes (Vint.) of these molecules have been calculated by applying Tammann–Tait–Gibson (TTG) equation of state. It is being observed that intrinsic volume differs appreciably from the value based upon EG and PEG–300 in a liquid state as a standard state. The excess volume change (V¯20E=V¯20-V¯int.0) values are found to be −16.1 and −63.8⋅10–6 m3⋅mol−1 for EG and PEG–300, respectively. Similar calculations made for PEG–300 in CCl4 medium also yield excess volume change of −60⋅10–6 m3⋅mol−1 magnitude. These results are explained on the basis of three dimensional hydrogen bonded structure of EG and the linkage ▪ interaction with solvent water having a presence of helical segments. The inferences drawn will be of help to understand the weak denaturing interactions of glycols in protein denaturation studies.

Enhancement of Adhesion Characteristics of Low-Density Polyethylene Using Atmospheric Plasma Initiated-Grafting of Polyethylene Glycol.

The low-density polyethylene/aluminum (LDPE/Al) joint in Tetra Pak provides stability and strength to food packaging, ensures protection against outside moisture, and maintains the nutritional values and flavors of food without the need for additives in the food products. However, a poor adhesion of LDPE to Al, due to its non-polar surface, is a limiting factor and extra polymeric interlayers or surface treatment is required. Plasma-assisted grafting of the LDPE surface with different molecular weight compounds of polyethylene glycol (PEG) was used to improve LDPE/Al adhesion. It was found that this surface modification contributed to significantly improve the wettability of the LDPE surface, as was confirmed by contact angle measurements. The chemical composition changes after plasma treatment and modification process were observed by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). A surface morphology was analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Adhesion characteristics of LDPE/Al adhesive joints were analyzed by the peel tests. The most significant adhesion improvement of the PEG modified LDPE surface was achieved using 10.0 wt.% aqueous (6000 M) PEG solution, while the peel resistance increased by approximately 54 times in comparison with untreated LDPE.

Stabilizing Aqueous Three-Dimensional Printed Constructs Using Chitosan-Cellulose Nanocrystal Assemblies.

The assembly and binding of nanoparticles at the interfaces of aqueous two-phase systems enable the three-dimensional (3D) printing of all-aqueous naturally occurring materials. When a dispersion of cellulose nanocrystals (CNCs) in an aqueous solution of polyethylene glycol (PEG) is brought into contact with chitosan dissolved in an aqueous solution of dextran, the CNCs and chitosan diffuse to the interface between the two immiscible aqueous solutions, electrostatically interact, and form a solid, membranous layer sufficiently rapidly to 3D print tubules of one liquid in the other. The diameter, length, spatial arrangement, and stability of the printed tubules can be broadly controlled. Adsorption and directional diffusion of ionic species across the membranous layer make heavy metal ion removal possible. The results present a platform for fabricating and developing all-aqueous compartmentalized systems where function can be independently coupled to the inherent functionality of the nanoparticles or ligands.

A novel waterborne polyurethane coating modified by highly dispersed nano‐boron carbide particles

AbstractIn this study, waterborne polyurethane (WPU) coatings were modified by adding various compositions of nano‐boron carbide (nano‐B4C) particles. In order to achieve proper dispersion of nano‐B4C in WPU and increasing chemical interactions between them, the nano‐B4C particles were treated with polyethylene glycol (PEG) or polypropylene glycol (PPG). The modified surface and microstructure of nano‐B4C were characterized by Fourier transform infrared, scanning electron microscopy and transmission electron microscopy. The deposition experiment was designed to evaluate the dispersion effect of nano‐B4C in PEG or PPG aqueous solution. The physical performance of nano‐B4C modified WPU coatings was measured following the national standards of paints and vanishes. The results revealed that the PEG6000 not only enhanced the interaction between nano‐B4C and WPU but also exhibited a remarkable ability to improve the physical performance of WPU coating. The coating with 15 wt% of nano‐B4C addition exhibited the best performance in terms of abrasion and hardness, which could be attributed to the best uniform dispersion of nano‐B4C particles in PEG6000 aqueous solution.

Interfacial Microcompartmentalization by Kinetic Control of Selective Interfacial Accumulation.

Reported here is a 2D, interfacial microcompartmentalization strategy governed by 3D phase separation. In aqueous polyethylene glycol (PEG) solutions doped with biotinylated polymers, the polymers spontaneously accumulate in the interfacial layer between the oil‐surfactant‐water interface and the adjacent polymer phase. In aqueous two‐phase systems, these polymers first accumulated in the interfacial layer separating two polymer solutions and then selectively migrated to the oil‐PEG interfacial layer. By using polymers with varying photopolymerizable groups and crosslinking rates, kinetic control and capture of spatial organisation in a variety of compartmentalized macroscopic structures, without the need of creating barrier layers, was achieved. This selective interfacial accumulation provides an extension of 3D phase separation towards synthetic compartmentalization, and is also relevant for understanding intracellular organisation.

Interfacial Microcompartmentalization by Kinetic Control of Selective Interfacial Accumulation

AbstractReported here is a 2D, interfacial microcompartmentalization strategy governed by 3D phase separation. In aqueous polyethylene glycol (PEG) solutions doped with biotinylated polymers, the polymers spontaneously accumulate in the interfacial layer between the oil‐surfactant‐water interface and the adjacent polymer phase. In aqueous two‐phase systems, these polymers first accumulated in the interfacial layer separating two polymer solutions and then selectively migrated to the oil‐PEG interfacial layer. By using polymers with varying photopolymerizable groups and crosslinking rates, kinetic control and capture of spatial organisation in a variety of compartmentalized macroscopic structures, without the need of creating barrier layers, was achieved. This selective interfacial accumulation provides an extension of 3D phase separation towards synthetic compartmentalization, and is also relevant for understanding intracellular organisation.

Structural analysis of embedding polyethylene glycol in silica aerogel

Embedding of the functional materials into aerogel powders was realized via the filtration method. In this work, the effect of aerogel on the molecule structure of the embedded polyethylene glycol (PEG) was investigated by dispersing aerogel powders in 20 wt% PEG aqueous solution with subsequent filtration method. The encapsulation of the PEG in the aerogel was characterized by isothermal nitrogen (N 2 ) adsorption/desorption. The structure of the embedded PEG in the aerogel powders was investigated via SEM-EDS, FE-SEM, FT-IR, XRD. TG-DTA, DSC, and leakage test. It was found that the only physical capillary force worked to adsorb PEG molecules from its solution by the aerogel powders. The BET surface area and the DFT pore volume of the PEG/aerogel powders were reduced obviously when compared with pure aerogel powders. The ability of the pores in the aerogel powders ranging from 14 nm to 16 nm to adsorbing the PEG molecules from the water system was weak. The crystallinity of the PEG was significantly reduced because of the limited space for crystal growth, and the decomposed temperature and thermal capacity decreased correspondingly. • Selective adsorption of PEG by pores in aerogel. • Space limitation of PEG crystal growth in aerogel. • Stable thermal property of PEG/aerogel powders.

Effect of flow patterns on bovine serum albumin and ampicillin partitioning using aqueous two-phase systems in microdevice

The separation and purification of biomolecules via aqueous two-phase extraction (ATPE) has encountered a series of obstacles to its industrial implementation. Recently, the miniaturization of ATPE has attracted interest due to the increase of performance, the possibility of operating in a continuous mode, and easy to scale-up by numbering-up approach. However, there is a gap in the literature with regard to the effects of flow patterns on the partitioning of biomolecules using microdevices. Thus, the present study investigated the ATPE of bovine serum albumin (BSA) and ampicillin, a beta-lactam antibiotic, under different flow patterns (slug, droplet and parallel) by means of microdevices. The microdevices were manufactured with circular tubes in a senoidal shape and the ATPE were prepared from the mixture between aqueous solutions of polyethylene glycol (PEG) and dibasic potassium phosphate. Using 1.80 mm tubes, slug, droplet and parallel flow patterns were observed only in the PEG 1500/dibasic potassium phosphate system, while the parallel flow pattern was not stabilized in systems involving PEG 4000 and PEG 6000. Experiments using a droplet flow pattern showed higher values of recovery (56% after 10 min) and partition coefficient of BSA compared to the slug and parallel flow patterns. In experiments involving ampicillin, the extraction performance was practically independent of the flow patterns. The BSA recovery behaved as an inverse function of the diameter tubes, which achieved slightly superior performance than the batch experiment (67% after 10 min) using droplet flow pattern, 0.51 mm tubes and residence time of 10 min (69%).

Bending elastic modulus of a polymer-doped lyotropic lamellar phase

The effect of inserting a neutral water-soluble adsorbing polymer on the flexibility of amphiphilic bilayers in a lamellar phase is investigated. The Lα system is a stack of charged undulating bilayers composed of sodium dodecyl sulfate (SDS) and octanol separated by aqueous solutions of polyethylene glycol (PEG). The mean bending elastic modulus κ is determined from the quadrupole splittings in the solid state NMR spectra of the perdeuterated octanol chains embedded in the membranes that undergo collective fluctuations. Parameters for describing the membrane behavior (bilayer thickness, elastic compressibility modulus, order parameter) are obtained by supplementing the NMR data with complementary experiments (x-ray scattering), NMR spectral simulations, and theoretical considerations. A fairly complete picture of the membrane rigidity emerges for any location in the lamellar phase thanks to a broad sweep of the lamellar domain by systematically varying the membrane fraction along dilution lines as well as the polymer composition. The most remarkable result is the difference between dilute and semi-dilute regimes. In the dilute PEG solution, no (or slight positive shift) polymer contribution to the rigidity curvature of the layered system is noted within the experimental resolution (≤0.3 kBT) and κ remains around 2.7 kBT. In contrast, the membrane rigidity increases steadily upon polymer addition once the crossover concentration cp* is exceeded, amounting to a 60% increase in κ at polymer concentration 2.5 cp* in the aqueous interlayers. These results are discussed with regard to the theoretical expectation of membrane rigidification upon irreversible polymer adsorption.

Study on fall velocity of continuously ejected micro inkjet droplet

One of the most important design parameters for the inkjet printing device is the inkjet drop velocity, which changes along the falling path from the ejection out of a nozzle to the impact on a substrate. Therefore, in this study, the droplet velocity of the piezoelectric drop-on-demand inkjet was measured. The nozzle diameter was 70 µm and polyethylene glycol aqueous solution was used as ink. The inkjet droplets were generated within a range from 500 to 10000 Hz of frequencies at a reference piezoelectric input voltage. The successive inkjet droplets were captured by the high-speed camera with 100000 fps, then the inkjet droplet velocities were analyzed visually at each falling location. The velocity change of a drop up to its terminal velocity was calculated theoretically to be compared with the experimental results. This study found that the velocity of the continuously ejected droplets depended on the interval of the droplets, as well as the density and diameter of the droplet which are essential factors of the general velocity change of a falling drop. The inkjet droplets with the long interval can be considered as an independent droplet so that it can follow the terminal velocity curve of the general drop. However, the inkjet droplets with short interval have the higher velocity than the general terminal velocity curve. It is considered that each droplet gets into the wake field of the former droplet so that its drag force can decrease and the velocity can increase.

Experimental Measurement of Equilibrium Surface Tension of an Aqueous Solution of Polyethylene Glycol and a Surfactant

A device is designed and constructed for measuring the equilibrium surface tension of water and a number of other solutions. The measured equilibrium surface tension of water, as a reference fluid, has good consistency with literature data. Moreover, the equilibrium surface tension of the aqueous solutions of surfactants and polymer composed of sodium dodecyl sulphate (SDS), Triton CG-110, dimethyl di-dodecyl-ammonium bromide (DDAB), and polyethylene glycol (PEG) with different molecular weights of 200, 300, 400, and 600, as well as that of the ternary solutions of SDS/PEG/water, Triton CG-110/PEG/water, and DDAB/PEG/water at 293.15 K and atmospheric pressure are measured. The equilibrium surface tension of the aqueous solutions of PEG 600 are measured at 296.15 K because PEG 600 is solid at 293.15 K. The measured data are compared with the predictions of thermodynamic models, and the results show that Redlich-Kister (RK) model has the lowest error in predicting the experimental data.

(Invited) High Speed AFM Observation of PEG Additive Behavior Depending on Electrode Potential

1. Introduction Copper electrodeposition has still attracted many attention, since it is applied for the miniaturization of integrated circuits (ICs) and micro electro mechanical systems (MEMS). A damascene process is employed there and a copper wiring controlled on a nanoscale is made. By using a several kinds of additives which is classified into inhibitors, accelerators and levelers, void-free filling electrodeposition is possible. Each additive works by adsorbing on the substrate surface, and their synergistic effect enables the complete filling in the trench. Many studies have been reported on the adsorption mechanism of additives, which is analyzed by in-situ techniques under electrochemical environment [1]. However, since the adsorption of additives occurs at high speed in a fine region, it is very difficult to capture the phenomenon. We could observe the nucleation phenomenon of copper electrodeposition by using high-speed atomic force microscope (HS-AFM) [2, 3]. In this presentation, we will focus on polyethylene glycol (PEG), which is widely used as a copper plating inhibitor, and observe the adsorption / desorption behavior by using HS-AFM in order to investigation the suppression mechanism depending on electrode potential.2. Experimental Experiments were conducted in a three-electrode cell. The working electrode was an Au(100) single crystal (ϕ =3mm, MaTecK), the counter electrode was a platinum wire and the reference electrode was a palladium wire occluded with hydrogen. Prior to each experiment, the single crystal was annealed with a butane burner for a few seconds and then cooled in the atmosphere. The electrolyte was a mixture of 300 ppm PEG aqueous solution (Mw avg ~ 3000, Fujifilm Wako Chemicals) with 1.2 mM hydrochloric acid and 50mM sulfuric acid. Experiments were conducted with an electrochemical measurement system (HZ-7000, Hokuto Denko Co.). The constant potentials from − 0.5 V to 0.1 V were applied at room temperature. The ultra-short cantilevers (NanoWorld AG) were used as the tips for HS-AFM observation. In the present experiment, the scan area was in the range of 500-1000 nm2 and the scanning speed was 1 frame s-1. During the observation, the electrode potential was kept constant value, and the morphological change of the electrode surface was recorde 3. Results and discussion Fig. 1 shows HS-AFM images of PEG adsorption when the electrode potential was -0.10V. Initially at open circuit potential, smooth surface was observed after annealing [Fig. 1 (a)]. PEG adsorption occurred immediately after applying cathodic potential, and line-like PEG structure was formed along the steps edge after 5 s [Fig. 1 (b)]. After 10 s, the adsorbed PEG grew in one direction (as indicated by the arrow) and formed film shape [Fig. 1 (c)]. The growth rate was calculated to be 3.7 nm s-1 from image analysis. This rate was found to be very slow compared to the results of copper deposition in a copper sulfate solution without PEG. After that, the electrode surface was covered with PEG thin film [Fig. 1 (d)]. From the height analysis, the thickness of the PEG film was approximately 4 nm or less, and it was suggested that PEG was adsorbed with a certain thickness by comparing with the literature value [4]. The PEG film was stable at −0.10 V and did not become thicker even after keeping the cathodic potential. REFERENCES [1] Moffat T. P., Wheeler D., Kim S. K., Josell D., J. Electrochem. Soc, 153 (2006) C127.[2] Yoshioka T., Matsushima H., Ueda M., Electrochim. Acta, 302 (2019) 422.[3] Yoshioka T., Matsushima H., Ueda M., Electrochem. Commun., 92 (2018) 29.[4] Walker M. L, Richter L. J, Moffat T. P., J. Electrochem. Soc, 152 (2005) 403. Figure 1

An alternative approach for determining suction of polyethylene glycols for soil testing

Determination of suction of polyethylene glycol (PEG) is vital for unsaturated laboratory testing that uses the osmotic technique to study the hydromechanical behaviour of fine-grained soils. To date, suctions of PEG solutions have been either experimentally measured or calculated from established semi-empirical relationships between the concentration of PEG and the suction. This paper presents an alternative approach for determining suctions of aqueous PEG solutions based on a modified Flory–Huggins equation. Using the proposed method, suctions of various PEGs can be precisely calculated by knowing the average molar mass, concentration of the solution and an interaction coefficient, which represents the quality of the PEG–solvent interaction. The suggested method relies on the characteristics and thermodynamical behaviour of PEGs in solution. Experimental data of several PEG–water mixtures reported in the literature were analysed. The superiority of this approach remains with the abilities to verify the molar mass of PEGs and estimate the suctions of PEG at high concentrations.

Preparation of Activated Carbon Supported Bead String Structure Nano Zero Valent Iron in a Polyethylene Glycol-Aqueous Solution and Its Efficient Treatment of Cr(VI) Wastewater.

Nanometer zero-valent iron (nZVI) has been widely used in the treatment of heavy metals such as hexavalent chromium (Cr(VI)). A novel composite of bead string-structured nZVI on modified activated carbon (nZVI–MAC) is prepared here, using polyethylene glycol as the stable dispersant rather than traditional ethanol during the loading process. The microstructure characterization shows that nZVI particles are loaded on MAC with a bead string structure in large quantity and stably due to the addition of hydroxyl functional groups on the surface by polyethylene glycol. Experiments on the treatment of Cr(VI) in wastewater show that the reaction process requires only 20 min to achieve equilibrium. The removal rate of Cr(VI) with a low concentration (80–100 mg/L) is over 99% and the maximum saturation removal capacity is up to 66 mg/g. The system converts Cr(VI) to trivalent chromium (Cr(III)) through an oxidation-reduction effect and forms an insoluble material with iron ions by coprecipitation, which is then adsorbed on the surface of the nZVI–MAC. The process conforms to the quasi-second order adsorption kinetics equation (mainly chemical adsorption process).

Unconventional Complex Coacervation between Neutral Polymer and Inorganic Polyoxometalate in Aqueous Solution via Direct Water Mediation

Water, specifically in a hydration shell, is critical for many biological supramolecular aggregations in nature, where water can directly mediate intermolecular association via hydrogen bonding and is regarded as “structured water”. Conversely, little has been reported on the biomimetic water-mediated supramolecular assembly with adequately high water content to date, because of the competing thermodynamic processes of water hydration and water as a building block to participate in self-assembly. In this work, we explore water-mediated complexation based on entropy-driven biphasic coacervate formation using highly hydrophilic neutral polymer and inorganic mineral-analogous nanoclusters. For the first time (to the best of our knowledge), nonelectrostatic liquid–liquid separating coacervate formation is demonstrated between polyethylene glycol (PEG) and polyoxometalate (POM) nanoclusters in aqueous solutions of varied PEG and POM concentrations, POM types, and aqueous medium conditions. Comprehensive charac...

Core-shell-corona chitosan-based micelles for tumor intracellular pH-triggered drug delivery: Improving performance by grafting polycation

Core-shell-corona chitosan-based micelles were designed for the tumor intracellular pH-triggered doxorubicin (DOX) delivery, via a facile in-situ micellization in an aqueous solution of DOX and polyethylene glycol (PEG) and poly(2-(diisopropylamino) ethyl methacrylate) (PDPA) dual-modified chitosan (PEG-g-CS-g-PDPA). The effect of the PDPA modification on the diameter, drug loading-capacity (DLC) and pH-triggered drug release was investigated for the three different polymerization degrees of PDPA (25, 32, and 42) with a similar modification degree of ~22%. The optimized ones, the core-shell-corona DOX/PEG-g-CS-g-PDPA32 micelles possessed a mean hydrodynamic diameter (Dh) of 211 nm and DLC of 54%, showing an excellent pH-triggered drug release with negligible premature drug leakage in 60 h. Such results indicated that grafting polycation could efficiently improve the performance of the chitosan-based drug delivery system (DDS) for tumor chemotherapy.