Optimization of the Properties of Photocured Hydrogels for Use in Electrochemical Capacitors

In this work, hydrogel polymer electrolytes (HPEs) were obtained by the photopolymerization of a mixture of two monomers: Exothane 8 (Ex8) and 2-hydroxyethylmethacrylate acid phosphate (HEMA-P) in an organic solvent N-methyl-2-pyrrolidone (NMP), which was replaced after polymerization with water, and then with the electrolyte. The ratio of monomers as well as the concentration of NMP was changed in the composition to study its influence on the properties of the HPE: conductivity (electrochemical impedance spectroscopy, EIS) and mechanical properties (puncture resistance). Properties were optimized using a mathematical model to obtain a hydrogel with both good mechanical and conductive properties. To the best of our knowledge, it is the first publication that demonstrates the application of optimization methods for the preparation of HPE. Then, the hydrogel with optimal properties was tested as a separator in a two-electrode symmetric AC/AC pouch-cell. The cells were investigated by cyclic voltammetry galvanostatic charge/discharge with potential limitation and EIS. Good mechanical properties of HPE allowed for obtaining samples of smaller thickness while maintaining very good dimensional stability. Thus, the electrochemical capacitor (EC) resistance was reduced and their electrochemical properties improved. Moreover, photopolymerization kinetics in the solvent and in bulk by photo-DSC (differential scanning calorimetry) were performed. The great impact on the polymerization of HEMA-P and its mixtures (with Ex8 and NMP) have strong intermolecular interactions between reagents molecules (i.e., hydrogen bonds).

Wettability and sound absorption of graphene oxide doped polymer hydrogel

In this paper, we introduce a nanocomposite as a humidity-sensitive sound absorber. The nanocomposites were prepared using hydrogel polymer (HP) as a matrix and graphene oxide (GO) as a filler. Results show that the surface energy of the nanocomposite is 58.4 mJ m−2, and GO sheets increase the nanocomposite porosity from 2.6716 cm2 g−1 (for HP) up to 3.246 cm2 g−1. In addition, the diameter of nanocomposite pores is 8.5202 nm lower than that of HP (10.274 nm). To study the effect of humidity on the sound absorption, we exposed them to moisture for 30 and 60 min and then measured sound absorption. Results show an absorption peak for the HP at 1022 Hz with an attenuation value of 30%, while the nanocomposite shows two main peaks around 1898 and 3300 Hz. In addition, results show that sound absorption peaks shift to higher frequencies according to humidification time.

In Situ Photopolymerization of Acrylamide Hydrogel to Coat Cellulose Acetate Nanofibers for Drug Delivery System

In this study we developed electrospun cellulose acetate nanofibers (CANFs) that were loaded with a model non-steroidal anti-inflammatory drug (NSAID) (ibuprofen, Ib) and coated with poly(acrylamide) (poly-AAm) hydrogel polymer using two consecutive steps: an electrospinning process followed by photopolymerization of AAm. Coated and non-coated CANF formulations were characterized by several microscopic and spectroscopic techniques to evaluate their physicochemical properties. An analysis of the kinetic release profile of Ib showed noticeable differences due to the presence or absence of the poly-AAm hydrogel polymer. Poly-AAm coating facilitated a constant release rate of drug as opposed to a more conventional burst release. The non-coated CANFs showed low cumulative drug release concentrations (ca. 35 and 83% at 5 and 10% loading, respectively). Conversely, poly-AAm coated CANFs were found to promote the release of drug (ca. 84 and 99.8% at 5 and 10% loading, respectively). Finally, the CANFs were found to be superbly cytocompatible.

Towards Smart Drug Delivery: Exploration Of A Molecularly Imprinted Polymer Network

The current study explores the concept of Molecular Imprinting Technology (MIT) and evaluates the ability of a molecularly imprinted hydrogel polymer (MIP) to preferentially uptake the template drug propranolol from aqueous solution. The extent of the molecular affinity and recognition was challenged by introducing a secondary competing structure during uptake. The release of propranolol as a response to environmental stimuli was investigated. The MIP was synthesized with copolymers methyl methacrylate (MMA) and N,N-dimethyl acrylamide (DMAA). Morphology was studied by scanning electron microscopy (SEM), ptake, displacement, and release experiments were studied by fluorescence spectroscopy. The SEM studies did not indicate the presence of molecularly imprinted cavities. The MIPs demonstrated preferential uptake in comparison to the non-imprinted (NIP) counterpart. The displacement studies revealed that uptake by the MIP is not very selective. The release studies demonstrated that ropranolol release can be tailored to respond to environmental stimuli such as temperature and, especially, pH.

Towards Smart Drug Delivery: Exploration Of A Molecularly Imprinted Polymer Network

The current study explores the concept of Molecular Imprinting Technology (MIT) and evaluates the ability of a molecularly imprinted hydrogel polymer (MIP) to preferentially uptake the template drug propranolol from aqueous solution. The extent of the molecular affinity and recognition was challenged by introducing a secondary competing structure during uptake. The release of propranolol as a response to environmental stimuli was investigated. The MIP was synthesized with copolymers methyl methacrylate (MMA) and N,N-dimethyl acrylamide (DMAA). Morphology was studied by scanning electron microscopy (SEM), ptake, displacement, and release experiments were studied by fluorescence spectroscopy. The SEM studies did not indicate the presence of molecularly imprinted cavities. The MIPs demonstrated preferential uptake in comparison to the non-imprinted (NIP) counterpart. The displacement studies revealed that uptake by the MIP is not very selective. The release studies demonstrated that ropranolol release can be tailored to respond to environmental stimuli such as temperature and, especially, pH.

Graphene Oxide–Polymer Hydrogel: Wettability and Sound Absorption

In this paper, we introduce a nanocomposite as a humidity-sensitive sound absorber. The nanocomposites were prepared using hydrogel polymer (HP) as a matrix and graphene oxide (GO) as a filler. Results show that the surface energy of the nanocomposite is 58.4 mJm-2, and GO sheets increase the nanocomposite porosity from 2.6716 cm2 g-1 (for HP) up to 3.246 cm2 g-1. In addition, the diameter of nanocomposite pores is 8.5202 nm lower than that of HP (10.274 nm). To study the effect of humidity on the sound absorption, we exposed them to moisture for 30 and 60 min and then measured sound absorption. Results show an absorption peak for the HP at 1022 Hz with an attenuation value of 30%, while nanocomposite shows two main peaks around 1898 and 3300 Hz. In addition, results show that sound absorption peaks shift to higher frequency according to humidification time.

Low-frequency electromagnetic field and hydrogel to increase survival rate and growth of European spruce (Picea abies L.) seedlings

This paper presents the results of a study that was conducted in the Sergiev Posad forestry of the Moscow region forestry Department with the participation of the laboratory of the Department of Forest crops, breeding and dendrology of the BMSTU (Mytishchi branch). This study shows the technology of planting European (Picea abies L.), seedlings in culture, which can significantly increase the survival rate of experimental samples and improve their biometric characteristics: height, diameter of the root neck, weight, and also the anatomical structure of seedlings. The experiments were performed using a low-frequency generator «Rost-Active», the author’s technology pre-sowing treatment of seeds and seedlings by an electromagnetic field, hydrogel (polymer water-retaining agent) and a method of histometric analysis of cross sections of control and experimental stems of European spruce seedlings. The results of the study indicate a clear positive effect of electromagnetic field and hydrogel on the increase in survival of experimental samples of seedlings of common European spruce in relation to the control. Also, the results of comparative histometric analysis indicate the effectiveness of methods for treating pine seedlings with low-frequency EMF and applying hydrogel to the soil.