By combining ATRP, dendrimer chemistry and 'click' reactions, a library of novel linear dendritic block copolymers (hybrids) was successfully synthesized. The isolated polymers displayed hydrophilic alkyne groups and T-g's ranging from 14 degrees C to 67 degrees C. A T-g threshold of 39 degrees C was found necessary for straightforward porous membrane fabrication via the breath figure method. Exploiting the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction, a robust and benign protocol was identified enabling surface functionalization under aqueous conditions. Such manipulations included the introduction of fluorescent rhodamine for thorough assessment by confocal fluorescence microscopy as well as polyethylene glycol chains or perfluorinated groups for tuning the membrane wettability. Finally, with the initial indication of being nontoxic to human dermal fibroblasts (hDF) and osteoblast-like MG63, the porous membranes can potentially find use in the field of controlled cell culture such as patterning of cell growth.

A new generation of honeycomb membranes is herein described from a novel library of multipurpose linear-dendritic block copolymers. These are accomplished by combining atom transfer radical polymerization together with dendrimer chemistry and click reactions. The resulted amorphous block copolymers, with T-g between 30 and 40 degrees C, display three important functions, i.e., pore generating aromatic groups, crosslinking azides, and multiple dendritic functional groups. All block copolymers enable the successful fabrication of honeycomb membranes through the facile breath figure method. The peripheral dendritic functionality is found to influence the porous morphologies from closed pored structure with pore size of 1.12 mu m(2) to open pore structure with pore size 10.26 mu m(2). Facile UV crosslinking of the azides yields membranes with highly durable structural integrity. Upon crosslinking, the pH and thermal stability are extended beyond the noncrosslinked membranes in which the porous integrity is maintained up to 400 degrees C and pH 1-14. Taking into account the straightforward and cost-efficient strategy to generate ordered, functional, and structurally stable honeycomb membranes on various solid substrates, it is apparent that these multipurpose block copolymers may unlock future applications including use as molds for soft lithography.

A facile methodology for the fabrication of functional crosslinked three dimensional (3D) networks has herein been explored via the benign and UV initiated thiol-ene coupling (TEC) chemistry. The careful selection of monomers or polymers and their feed ratio resulted in straightforward design of organic, inorganic and hydrogel networks with readily available alkenes or thiol functional groups. All crosslinked networks were fabricated within 1 second of UV exposure at wavelengths of 320-390 nm and generally exhibited excellent gel fractions around 90%. By introducing off-stoichiometric thiol and ene (OSTE) monomer feed ratios the window of mechanical properties could be manipulated. For the organic triazine system, the Young's modulus was altered from 780 MPa at an equimolar monomer ratio to soft 106 kPa for 2.5 equiv. with excess of thiol compared to enes. Postfunctionalizations with hydrophilic polyethylene glycols or acrylic acid and hydrophobic heneicosa-fluorododecyl acrylate were explored for the manipulation of functional networks. In this case, the rigid networks with excess of thiols were used as model substrates of which the initial contact angle (CA) of 60 degrees was decreased to 43 degrees by the introduction of acrylic acid and increased to 140 degrees by successful attachment of fluorinated molecules. Finally, amalgamating micropatterning strategy with simple postfunctionalizations of hydrophobic groups resulted in superhydrophobic rigid surfaces with a CA of 173 degrees.

Dendritic hydrogels from dendritic-linear-dendritic (DLD) block copolymers based on PEG and bis-MPA dendrons were constructed via UV-initiated thiol-ene, thiol-yne, CuAAC, and amine-NHS crosslinking chemistries. Stoichiometric ratio manipulations, prior to film formation, resulted in functional hydrogels with tuneable compressive moduli. The highest gel fractions for all networks were obtained at off-stoichiometric ratios with surplus of DLDs. Finally, sustainable networks were fabricated by amalgamating DLD, naturally abundant cellulose nanocrystal, and protein-based bovine serum albumin.