Piotr Stanislaw Mazurek

Preparing mono-dispersed liquid core PDMS microcapsules from thiol–ene–epoxy-tailored flow-focusing microfluidic devices

An applied dual-cure system based on thiol–ene and thiol–epoxy “click chemistry” reactions was proved to be an extremely effective and easy to use tool for preparing microfluidic chips, thereby allowing for precise control over material properties and providing the possibility of covalently bonding chip wafers. Different thiol–ene–epoxy-based polymer compositions were tested with the help of DSC and ATR FTIR, in order to investigate their physical and chemical properties. Water contact angles were determined, thus verifying the high efficiency and selectivity of the chemical surface modification of compositions in relation to high hydrophilicity and hydrophobicity. An obtained microfluidic device was subsequently used in order to produce PDMS microcapsules of very narrow size distribution and which contained various common liquids, such as water and ethanol, as well as an ionic liquid 2-hydroxyethylammonium formate.

A simple method for reducing inevitable dielectric loss in high-permittivity dielectric elastomers

Commercial viability of dielectric elastomers (DEs) is currently limited by a few obstacles, including high driving voltages (in the kV range). Driving voltage can be lowered by either decreasing the Youngs modulus or increasing the dielectric permittivity of silicone elastomers, or a combination thereof. A decrease in the Youngs modulus, however, is often accompanied by a loss in mechanical stability, whereas increases in dielectric permittivity are usually followed by a large increase in dielectric loss followed by a decrease in breakdown strength and thereby the lifetime of the DE. A new soft elastomer matrix, with high dielectric permittivity and a low Youngs modulus, aligned with no loss of mechanical stability, was prepared through the use of commercially available chloropropyl-functional silicone oil mixed into a tough commercial liquid silicone rubber silicone elastomer. The addition of chloropropyl-functional silicone oil in concentrations up to 30 phr was found to improve the properties of the silicone elastomer significantly, as dielectric permittivity increased to 4.4, dielectric breakdown increased up to 25% and dielectric losses were reduced. The chloropropyl-functional silicone oil also decreased the dielectric losses of an elastomer containing dielectric permittivity-enhancing TiO2 fillers. Commercially available chloropropyl-functional silicone oil thus constitutes a facile method for improved silicone DEs, with very low dielectric losses.

Novel encapsulation technique for incorporation of high permittivity fillers into silicone elastomers

The research on soft elastomers with high dielectric permittivity for the use as dielectric electroactive polymers (DEAP) has grown substantially within the last decade. The approaches to enhance the dielectric permittivity can be categorized into three main classes: 1) Mixing or blending in high permittivity fillers, 2) Grafting of high permittivity molecules onto the polymer backbone in the elastomer, and 3) Encapsulation of high permittivity fillers. The approach investigated here is a new type of encapsulation which does not interfere with the mechanical properties to the same content as for the traditionally applied thermoplastic encapsulation. The properties of the elastomers are investigated as function of the filler content and type. The dielectric permittivity, dielectric loss, conductivity, storage modulus as well as viscous loss are compared to elastomers with the same amounts of high permittivity fillers blended into the elastomer, and it is found that the encapsulation provides a technique to enhance some of these properties.

Glycerol-silicone elastomers as active matrices with controllable release profiles

Drug release regimes must be controlled for the optimal therapeutic effect. Although it is relatively straightforward to create first-order release matrices, it can be challenging to avoid an initial burst. Matrices with zero-order profiles are perceived to be beneficial in many cases but are even more difficult to formulate. We describe the straightforward synthesis of elastomeric composites prepared from silicone in which the active substance is dispersed in glycerol. The release of glycerol-soluble actives from the films of these materials was shown to be tunable with respect to the order of release (zero- or first-order) simply by changing the glycerol content. Importantly, release from the elastomers showed no burst effect. The discrete glycerol domains embedded within a silicone matrix act as reservoirs for active substances. Upon contact with aqueous media, the active substances are released from the matrices exhibiting zero-order, near zero-order, or first-order release kinetics. Various parameters that could influence the release process, including glycerol content, glycerol domain size, or membrane thickness, are thoroughly investigated, elucidating guidelines for creating matrices capable of delivering the active substances at desired rates. Additionally, the composites proved to absorb significant amounts of liquid water (up to 1850% of sample mass), a feature that can be tuned by the manipulation of the composite structure.

Advanced Wound Care Adhesives with New Functional Properties

Silicone_days.pdf. Embargo ended: 09/09/2018 Research output: Contribution to conference › Conference abstract for conference – Annual report year: 2018 › Research › peer-reviewObjective: To investigate the effects of clearing the Governor Vessel and refreshing the mind needling in neural development and remediation of children with cerebral palsy. Methods: 200 cases of children with cerebral palsy were randomly divided into the treatment group (n = 100) and the control group (n = 100). The treatment group was given the combined therapy of acupuncture and rehabilitation training, and the chosen acupoints were 13 points of the Governor Vessel, Shenshu (BL 23), Taixi (KI 3), Yanglingquan (GB 34), Zusanli (ST 36) and Sanyinjiao (SP 6), and points of refreshing the mind were also selected, which included puncturing Shenting (GV 24) toward Qianding (GV 21), puncturing Qianding (GV 21) toward Baihui (GV 20), puncturing Baihui (GV 20) toward Naohu (GV 17) and Sishencong (Ex-HN 1). The control group was only treated with rehabilitation training. A contrastive analysis of the therapeutic effect of acupuncture combined with rehabilitation training and pure rehabilitation training was made after a treatment course of 3 months. The Gross Motor Function Measure (GMFM) and Beijing Gesell Developmental Scale were adopted to assess the neural development and rehabilitation outcomes of the two groups. In addition, skull CT/MRI was adopted to evaluate the plerosis of injured cerebral nerve after treatment. Results: The total effective rate in treatment group was 87%, significantly higher than the 55% in the control group. The children’s development quotient (DQ) tested by Gesell Developmental Scale and scores tested by GMFM in the treatment group was obviously higher than the control group (P < 0.01). The improving and curing rates presented by skull CT/MRI in the treatment group were higher than the control group (P < 0.01). Conclusions: Clearing the Governor Vessel and refreshing the mind Needling could accelerate the recovery of injured brain nerve and the reconstruction of brain function. The acupuncture therapy could ameliorate both the motor development and cognitive development. On the other hand, the forward curative effect of acupuncture combined with rehabilitation training was significantly better than the pure rehabilitation training. Correspondence to: Liu ZH, Cerebral Palsy Rehabilitation Center of Nanhai Maternity and Children Hospital Affiliated to Guangzhou University of Chinese Medicine (Foshan 528200) Guicheng borough, Nanhai, Foshan city, Guangdong province, China. 528200. Tel: 0757-86232936; Email: Lzh1958424@163.comStatement of Problem: Diacerine (DCN) is a semi-synthetic anthraquinone anti-osteoarthritis drug; its poor solubility and limited dissolution profile lead to poor systemic bioavailability. In attempt to improve solubility and dissolution rate of DCN with response surface methodology, ternary solid dispersions were prepared with Pluronic F127 (PF127), Solutol HS 15 as surfactants and poly ethylene glycol 35K as carrier by ordinary fusion method. The interaction of DCN with PF127, Solutol HS 15 and PEG 35K has been evaluated by Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectrometry (FTIR) and Scanning Electron Microscopy (SEM) in all solid ternary systems.

Novel high dielectric constant hybrid elastomers based on glycerol-insilicone emulsions

Novel hybrid elastomers were prepared by speed-mixing of two virtually immiscible liquids - glycerol and polydimethylsiloxane (PDMS) prepolymer. Upon crosslinking of the PDMS phase of the resulting glycerol-in-silicone emulsion free-standing films were obtained. In this way glycerol became uniformly distributed within PDMS in shape of discrete droplets thus acting as a high dielectric constant filler efficiently enhancing the dielectric constant of the composites. Low- and high-voltage dielectric spectroscopy measurements were conducted in order to verify applicability of the composites as dielectric elastomer actuators. Conductivities of samples based on various PDMS compositions with different loadings of embedded glycerol were thoroughly investigated providing useful information about the dielectric behavior.