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Star-shaped polymers exhibit lower hydrodynamic volume, glass transition temperature, critical micelles concentration (CMC), and higher viscosity and drug-loading capacity compared to their linear counterparts. In the present study, amphiphilic biodegradable 4-arm star-shaped block copolymers, based on poly(ethylene oxide) (PEO) as a hydrophilic part and poly(3-caprolactone) (PCL) as a hydrophobic segment, are synthesized by ring-opening polymerization of 3-caprolactone employing pentaerythritol as an initiator and stannous octoate as a catalyst, followed by the coupling reaction with carboxyl-functionalized monomethoxy poly(ethylene oxide) (MeO-PEO-COOH). The structures of intermediates were deduced through 1 H-NMR and FT-IR spectroscopy. Average chemical composition of the star block copolymer is determined by proton NMR. Information related to molar mass distribution of targeted products and their precursors is obtained by size exclusion chromatography (SEC). However, due to its inherent poor resolution SEC could not reveal whether all the parent homopolymers are coupled to each other or remained unattached to the other segment. In order to comprehensively characterize the synthesized star-block copolymers, liquid chromatography at critical conditions of both blocks is employed. The study allowed for separation of homopolymer precursors from targeted star-block copolymers. The study exposed heterogeneity of star block copolymers that was not possible by conventional techniques.

Amphiphilic block copolymers have been the subject of great scientific interests due to their applications in various fields including nano drug delivery. Three amphiphilic block copolymers based on poly(ε-caprolactone) as a hydrophobic segment and methoxy poly(ethylene oxide) ( as a hydrophilic part were synthesized by the ring-opening polymerization of ε-caprolactone using MeO-PEO 5K as macroinitiator by varying initial feed ratios. The synthesized polymers were further explored for their drug delivery potential using clotrimazole as model hydrophobic drug. Drug-loaded micelles were characterized for shape, size, drug encapsulation efficiency, in vitro release, and thermal stability using atomic force microscope, zetasizer, UV-visible spectrophotometry, FTIR, differential scanning calorimetry, and thermogravimetric analysis. Clotrimazole loaded in micelles were also investigated for its antifungal activity through an in vitro assay and scanning electron microscopy. The antifungal activity of drug increased significantly by delivering through polymeric micelles. Current study provides insight into different factors that can be maneuvered to achieve a variety of desired properties of micelles for improved therapeutic efficacy of drugs like clotrimazole.

Amphiphilic di- and tri-block copolymers based on poly(ethylene oxide) as a hydrophilic segment and poly(ε-caprolactone) as a hydrophobic part are synthesized by the ring-opening polymerization of ε-caprolactone while using poly(ethylene glycol)s and methoxy poly(ethylene glycol)s of varying molar masses as macro-initiators. The synthesized block copolymers are characterized with respect to their total relative molar mass and its distribution by size exclusion chromatography. Liquid chromatography at critical conditions of both blocks is established for the analysis of individual block lengths and tracking presence of unwanted homopolymers of both types in the block copolymer samples. New critical conditions of polycaprolactone on reversed phase column are reported using organic mobile phase. The established critical conditions of polycaprolactone extended the applicable molar mass range significantly compared to already reported critical conditions of polycaprolactone in aqueous mobile phase. Block copolymers are also analyzed at critical conditions of poly(ethylene glycol). Complete analysis of the di- and tri-block copolymers at corresponding critical conditions provided a fair estimate of molar mass of non-critical block besides information regarding presence of homopolymers of both types in the samples.

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This study reports the synthesis of well-defined polymers of vitamin B5 analogous methacrylamide (poly­(B5AMA)) using the reversible addition fragmentation chain transfer polymerization method. The prepared telechelic poly­(B5AMA) with a predicted molecular weight and narrow polydispersities are grafted onto silanized glass surfaces using a “grafting to” approach. The polymer-treated samples are characterized for the water contact angle and surface roughness properties, as a function of polymer size and density of the polymers grafted onto the glass slides. The antifouling behavior of poly­(B5AMA)-grafted glass slides is then studied and compared with that of PEGylated glass slides, upon treatment with a variety of proteins and bacteria. The functionalized surfaces exhibit remarkable antifouling properties that are found to be dependent on both the density and the molecular weight of the grafted polymers.

Development of facile, on-spot, robust, and efficient optical nanosensors for drugs and pesticides is one of the active research area. In this study, a nanosensor based on fairly stable silver nanoparticles (AgNPs) conjugated with specially designed thiourea (TU)-based molecule, N-((4'-methoxy-2'-nitrophenyl) carbamothioyl) dodecanamide (TU3), was prepared using one pot protocol and characterized by Ultraviolet (UV)-Visible spectroscopy, dynamic light scattering (DLS), fourier transform infrared (FTIR) spectroscopy and atomic force microscopy (AFM). The TU3 conjugated AgNPs (TU3-AgNPs) were found to be selective spectrophotometric sensor for an antimicrobial drug, amlodipine (Ad), among the pool of different drugs. TU3-AgNPs based nanosensor allows for the rapid quantitative assay having a detection limit of 0.3 μM in an analytical range of 0.1-100 μM. The proposed sensor is specific in presence of number of other interfering drugs and other matrix. Upto the best of our literature survey, this is first ever colorimetric sensor for quantification of amlodipine in complex matrix. The specificity of the sensor allows for quantitative detection of amlodipine in environmental, biological and pharmaceutical samples.

In this study, the surface morphologies of poly(2-vinyl pyridine-block-methyl methacrylate), P(2VP-MMA), copolymer films were analyzed by atomic force microscopy. P(2VP-MMA) samples varying in total molar mass and individual block length were evaluated for variations in the surface morphologies of films cast from toluene on Si wafers. The incorporation of AuNPs into the polymer domain significantly influenced the surface morphology of the films. Variations in the surface morphology as a function of the polarity of the casting solvent were also examined. In this context toluene (a non-polar solvent), chloroform (of intermediate polarity)and ethyl acetate (a polar solvent) were employed as casting solvents. Toluene is a good solvent for PMMA compared to P2VP, chloroform has no preferential solvation, while ethyl acetate is a good solvent for P2VP compared to PMMA. The morphology of the films cast on substrates of distinctly different polarities, such as mica, Si wafers, and HOPG, were studied to appraise their selectivity. Finally, a detailed study of the effects of thermal annealing on the surface morphologies of P(2VP-MMA) and P(2VP-MMA)-AuNPs was conducted. Fig. 12 AFM 3D phase images of P(2VP 15 -MMA 85 ) cast from chloroform on substrates of varying polarity, demonstrating substrate selectivity for the surface morphology: (A) HOPG, (B) Si wafer, (C) mica.This journal is