Unspecific interactions, at the interface between a synthetic material and an aqueous biological environment, leading to irreversible protein adsorption can cause to undesired consequences. These include fouling of a boat hull or a triggered immune response. Thus, stealthy materials are a topic that has generated a great deal of interest in the scientific community. This work deals with the design of networks, nanoparticles, and surfaces containing poly(ethylene glycol) (PEG), known for its resistance to protein adsorption and non-toxic nature. Initially, PEG-based networks, hydrogels, were synthesized using photoinduced thiol-ene chemistry in order to afford coatings targeted for marine antifouling applications. By varying the length of the PEG chain, curing chemistry, cross-linker as well as hydrolytical stability, a library of hydrogel coatings was produced. The coatings were subsequently characterized with respect to curing efficiency, thermal and mechanical properties, and aqueous stability. Furthermore, the antifouling properties of coatings were evaluated using in vitro tests with proteins, marine bacteria, and diatoms. As a final test the coatings were evaluated in a four month field test. It was found that coatings comprising longer PEG chains displayed enhanced antifouling performance, compared to shorter PEGs. In addition, the choice of cross-linker, curing chemistry, and hydrolytical stability also affected the properties to a great extent. This thesis further deals with the design of amphiphilic linear dendritic hybrids, with PEG as the hydrophilic block. Using non-toxic 2,2-bis(methylol) propionic acid (bis-MPA) based dendrons, bearing click functional cores (alkyne or allyl) and peripheral hydroxyl groups, as macrointitiators for ring-opening polymerization of ε-caprolactone, a library of star branched materials was afforded. As a final step, click functional (azide or thiol) PEGs were attached using copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) or thiol-ene click chemistry. The size of the dendrons was varied from generation 0-4, along with variation of both poly(ε-caprolactone) (PCL) length and PEG length. The materials were designed in order to allow a study of the impact of the dendron generation. Finally, the hybrid materials were used for the preparation of micelles, as well as for the formation of honeycomb membranes. The micelles critical micelle concentration, size and drug loading capacity were shown to be highly dependent on the generation of the dendron. The generation of the dendron also had a profound effect on the ability of the hybrid materials to form ordered honeycomb membranes, and hybrid materials of the 3rd generation yielded the most highly ordered membranes.

Ickespecifika interaktioner vid gränsytan, mellan ett syntetiskt material och en vattenbaserad biologisk miljö, kan leda till irreversibel adsorption av proteiner. Detta kan i sin tur leda till oönskade följdeffekter, såsom beväxning på båtskrov eller trigga en immunologisk reaktion. För att motverka dessa effekter har forskare utvecklat så kallade smygmaterial. Denna avhandling behandlar design av nätverk, nanopartiklar och ytor innehållande poly(etylenglykol) (PEG), som är känt för sina smygegenskaper och för att vara icke-toxiskt. Initialt behandlar avhandlingen PEG-baserade nätverk, hydrogeler, syntetiserade med fotoinitierad tiol-enekemi, för användning som beväxningsavvisande beläggningar för marina applikationer. Genom att variera olika parametrar, såsom längden på PEG-kedjan, härdningskemin, tvärbindaren samt den hydrolytiska stabiliteten, byggdes ett bibliotek av hydrogelbeläggningar upp. Hydrogelbeläggningarna karaktäriserades sedan med avseende på härdningseffektivitet, termiska och mekaniska egenskaper, samt hydrolytisk stabilitet. Vidare studerades beläggningarnas avvisande förmåga mot proteiner, bakterier samt kiselalger. Slutligen studerades ytbeläggningarna i ett fyra månader långt fälttest. Av testerna framgick att längre PEG-kedjor gav beläggningar med bättre avvisande förmåga. Dessutom framgick att valet av tvärbindare, härdningskemi samt hydrolytisk stabilitet var av betydelse för beläggningarnas effektivitet. Denna avhandling behandlar vidare design av amfifila linjära dendritiska hybridmaterial, med PEG som den hydrofila delen. Genom att använda icke-toxiska 2,2-bis(metylol)propionsyrabaserade dendroner, med en klickfunktionalitet i kärnan (alkyne eller allyl) och perifera hydroxylgrupper, som makroinitiatorer för ringöppningspolymerisation av ε-kaprolakton byggdes ett bibliotek av material upp. För att göra materialen amfifila, kopplades klickfunktionella PEG-kedjor (azid eller tiol) till kärnan med koppar(I)-katalyserad azid-alkyn cykloadditionskemi alternativt tiol-enekemi. Storleken på dendronerna varierades från generation 0-4, dessutom varierades längden på både poly(ε-kaprolakton)- och PEG-kedjorna. Materialen designades så att inverkan av dendrongenerationen kunde studeras. Slutligen användes dessa hybridmaterial för att framställa miceller samt isoporösa filmer. Micellernas kritiska micellbildningskoncentration, storlek samt förmåga att laddas med läkemedel visade sig vara mycket beroende av dendrongenerationen. Dendrongenerationen visade sig vidare även ha stor inverkan i hybridmaterialens förmåga att självorganisera sig till en isoporös struktur och material av tredje generationen gav de mest välordnade filmerna.

In the last decades, the fabrication of ordered nano- and microporous structures has attracted increasing interest due to their specific properties and multiple possible applications in electronics, as templates or in the biological field. The development of such materials has been favored by the introduction of the simple breath-figure templating method in the 1990’s. In order to fully exploit the potential of these porous materials, the use of advanced functional molecules as precursors is essential. One suitable class of molecules is the well-defined linear-dendritic hybrids (LD hybrids) family. The structural variations, multiple end-groups and possible amphiphilicity of these molecules are significant advantages that could lead to highly sophisticated functional materials with potential usage in biology. Therefore, this project was directed towards the synthesis of advanced LD hybrids and the evaluation of their ability to form ordered functional porous films.

A degradation and toxicity study was initially conducted on polyester-based 2,2-bis(methylol)propionic acid (bis-MPA) dendrimers under physiological conditions to support the potential usage of these molecules for biological purposes. The materials were found to undergo a relatively fast depolymerization process at pH 7.5. Moreover, the initial dendrimer and its decomposition products were proven to be non-toxic for immune competent cells, allowing for the utilization of these molecules for biological applications.

A linear-dendritic-linear hybrid library was successfully synthesized from biocompatible poly(ethylene glycol) (PEG), poly(ε-caprolactone) (PCL) and bis-MPA building blocks using a combination of ring-opening polymerization (ROP)and copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC). The materials, consisting of one long PEG block connected to the focal point of the dendron and several PCL arms attached at its periphery, were used to construct ordered porous films using the breath figure method. The polymeric architecture strongly affected the ordering of the films with a more regular morphology obtained from a more flexible polymer. Changing the semi-crystalline PCL to amorphous polylactide (PLA) also permitted the formation of porous arrays. Interestingly, films obtained from inverted structures possessing one long PCL block and several short PEG chains, also presented a regular morphology. Moreover they could be activated to exhibit multiple surface hydroxyl groups.

To increase the number of orthogonal synthetic methodologies available for the preparation of advanced macromolecules, high molecular weight dendritic macrothiols were synthesized. These molecules were efficiently coupled to a number of core molecules via thiol-ene coupling, generating a comprehensive library of dendritic materials. This approach represents an attractive alternative to the commonly used, but potentially toxic, CuAAC.

Exploiting the obtained results, a final LD hybrid was synthesized from atom transfer radical polymerization (ATRP) of 2-hydroxyethyl methacrylate (HEMA) derivatives and thiol-ene coupling (TEC) with macrothiols. This macromolecule was successfully utilized to form functional ordered porous arrays and the availability of peripheral alkyne functional groups was demonstrated by efficient coupling with fluorescent Rhodamine-B. The HEMA-backbone allowed for the introduction of cross-linkable azide groups that were used to significantly improve the thermal stability of the films from 50 °C to 200 °C. These materials have the potential to be used in applications such as catalysis, in medicine and as sensors.