No abstract

New type of carriers based on grafted poly(ionic liquid)s was designed for delivery of ionically attached salicylates (Sal). Choline derived ionic liquid monomeric units were successfully introduced with various content in the side chains by the controlled radical polymerization. Properly high amounts of ionic pharmaceutics in the polymer systems were achieved by the well-fitted length and grafting degree of the side chains. In aqueous solution the graft copolymers were self-assembled into the spherical superstructures with sizes up to 73 nm. Delivery studies showed “burst” release within 4 h, after that it was slower yielding ~70% of released drug within 80 h. Proposed nanocarriers supported low toxicity against human cells (NHDF and BEAS-2B), anti-inflammation activity evaluated with the use of pro-inflammatory interleukins (IL-6 and IL-8) and antibacterial activities towards E. coli. Adjustment of ionic drug content by structural parameters of graft copolymers, including grafting degree and graft length, are advantageous to tailor nanocarriers with self-assembly properties in aqueous media. Effective release process by ionic exchange and biological activity with low toxicity are promising for further development of this type of drug delivery (DDS).

Poly[trimethylammonium (meth)acrylate]s decorated by salicylate anions were investigated as drug carriers. Efficient exchange of drug was provided by phosphate anions contained in the medium within 4 h.

Copolymers of [2-(methacryloyloxy)ethyl]trimethylammonium chloride, salicylate or bis(trifluoromethanesulfonate)imide (Cl − , Sal − or Tf 2 N − ), and methyl methacrylate (MMA) were synthesized by atom transfer radical polymerization (ATRP). The effect of different molar fractions of ionic monomer (0.05−1.0) on physicochemical properties was investigated. The relative reactivity ratios of MMA and ionic monomer with the chloride anion (0.88 and 1.13, respectively) were determined by the linearization Jaacks method. The particles formed in water by copolymers with trimethylammonium chloride (≥50 mol %) reached sizes below 10 nm, whereas salicylate-containing copolymers supported strong self-assembly, yielding 200 nm superstructures. The copolymers, after modification by the exchange of Cl − and Sal − with Tf 2 N − , demonstrated the influence of the anion on solubility, glass transition temperature, and morphology. The anionmodified trimethylammonium copolymers, compared with those directly synthesized from Tf 2 N-containing monomer, indicated different properties. Both the chloride monomer (Cl − replaced by Sal − or Tf 2 N − ) and its copolymers are able to exchange anions, including biologically active ones, which extends their future applications as poly(ionic liquid)s with therapeutic properties for controlled drug delivery.

No abstract

A linear relationship between the α evaluated from DSC, FTIR and dc conductivity (from BDS) was found.

We examined the behavior of poly­(mercaptopropyl)­methyl­siloxane (PMMS), characterized by a polymer chain backbone of alternate silicon and oxygen atoms substituted by a polar pendant group able to form hydrogen bonds (−SH moiety), by means of infrared (FTIR) and dielectric (BDS) spectroscopy, differential scanning calorimetry (DSC), X-ray diffraction (XRD), and rheology. We observed that the examined PMMS forms relatively efficient hydrogen bonds leading to the association of chains in the form of ordered lamellar-like hydrogen-bonded nanodomains. Moreover, the recorded mechanical and dielectric spectra revealed the presence of two relaxation processes. A direct comparison of collected data and relaxation times extracted from two experimental techniques, BDS and rheology, indicates that they monitor different types of the mobility of PMMS macromolecules. Our mechanical measurements revealed the presence of Rouse modes connected to the chain dynamics (slow process) and segmental relaxation (a faster process), whereas in the dielectric loss spectra we observed two relaxation processes related most likely to either the association–dissociation phenomenon within lamellar-like self-assemblies or the sub-Rouse mode (α′-slower process) and segmental (α-faster process) dynamics. Data presented herein allow a better understanding of the peculiar dynamical properties of polysiloxanes and associating polymers having strongly polar pendant moieties.

Efficient ROP polymerization of ε-caprolactone, resulting in products characterized by high molecular weight of low dispersities, remains a challenging task and is currently an important matter of ongoing research, mostly due to the accompanying side reactions, i.e., hydrolysis and transesterification. Herein, we studied in detail the impact of 2D hard confinement on the progress and product of ring-opening polymerization (ROP) of ε-caprolactone with and without water acting as initiator in comparison to the macroscale conditions, where various forms (powder, sheet) of alumina were used. It turned out that applied aluminum oxide nanotemplates act as both catalyst and initiator (INICAT) of ROP nanopolymerization and seem to operate accordingly to the pseudoliving coordination− insertion mechanism, resulting in nanowires of PCL characterized by M n up to 53.5 kg/mol. Additionally, due to the applied confinement, the side reactions were successfully suppressed, resulting in macromolecules of moderate molecular weight distribution (Đ = 1.27−1.41) and unimodal GPC peaks. It can be related to the extremely short nanopolymerization time (around 40 min), which successfully counteracts side reactions to occur. Moreover, our data clearly indicated that nanoporous membranes favor the growth of polymer chains of similar length, resulting in low dispersity of produced macromolecules. We believe that presented data significantly broaden the current state of knowledge and allow for a better understanding of the processes taking place under confinement, which seem to be crucial in any further nanotechnology development.