The present study investigates the challenging approach of post-polymerization modification on polymers with a sterically demanding reaction center. Therefore, the general possibility to functionalize polymethylene moieties was investigated. Poly(benzyl 2-ylidene-acetate) was synthesized by polymerization of benzyl 2-diazoacetate utilizing [(L-prolinate)Rh^I(1,5-dimethyl-1,5-cyclooctadiene)] as a catalyst. Subsequently, the modification of C1 polymerized poly(benzyl 2-ylidene-acetate) with amines was analyzed and the obtained data set was compared with experimental data derived for the C2 analog poly(benzyl acrylate). This is the first study on post-polymerization modification utilizing densely functionalized polymethylenes as starting materials. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 686–691

Poly(pentafluorophenyl acrylate)-block-poly(N-isopropylacrylamide) (PPFPA-b-PNIPAM) is synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. Light-responsive moieties of ortho-nitrobenzyl (ONB)-protected diamine are partially introduced to the PFPA moieties via postpolymerization modification. The amphiphilic block copolymers are assembled into micelles in water. The ONB-protected diamine group in the micelle core is released upon UV irradiation, which subsequently induces an in situ cross-linking by a spontaneous reaction with the remaining PFPA groups in the core and yields stable cross-linked micelles. Micellization of the copolymers is confirmed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). 4-Nitro-7-piperazino-2,1,3-benzoxadiazole (NBD) and pyrene are loaded in the core of cross-linked micelles to demonstrate the possibility for additional post-functionalization of residual PFPA moieties and hydrophobic molecule encapsulation, respectively. It is anticipated that these micelles can be alternative cargos for incorporating active compounds that may be useful for advanced applications. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1103–1113

A new 1,1-disubstituted-2-vinylcyclopropane monomer bearing a ketone and a pentafluorophenyl ester was synthesized and successfully polymerized to yield a polymer with two side chain moieties readily available for post-polymerization modification. After a quantitative modification of the pentafluorophenyl moiety with amines, a subsequent second functionalization reaction was successfully performed on the ketone moiety leading to a double side-chain functionalized polymer using two different routes. The first route utilized hydrazide and hydroxylamine derivatives leading to a ketone conversion of 25 to 85%. In the second route, the ketone moiety was first reduced to alcohol (reduction conversion up to 100%) and then converted into the corresponding ester or urethane using acyl halides or isocyanates, respectively, with a conversion ratio of up to 90%. A library of functionalized polymers was synthesized to confirm the effectiveness of this approach. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 2841–2849

Substituted polyphenylacetylenes featuring reactive pentafluorophenyl (PFP) ester moieties are synthesized. Parts of the reactive PFP groups are then converted with a mono ortho-nitrobenzyl-protected diamine in variable ratios. Thin films are prepared from these copolymers and irradiated with UV light (λ = 365 nm), resulting in crosslinking of the irradiated areas and hence enabling a photopatterning. We found that during the photocrosslinking process, the excess of PFP ester moieties is stable and remained intact, enabling a subsequent post-polymerization modification step with amines. Noteworthy, this subsequent modification with amines results in a dramatically shift in the UV–vis absorption spectra, rendering these patterned conjugated polymer films ideal candidates for optical sensors.

With a span as long as the history of polymer science itself, post-polymerization modification represents a versatile platform for the preparation of diversely functionalized polymers from a single precursor. Starting with the initial efforts by Staudinger in the 1920s, many of the early developments in modern polymer science can be attributed to the utilization of post-polymerization modification reactions. The scope of post-polymerization modification has greatly expanded since the 1990s due to the development of functional group tolerant controlled/living polymerization techniques combined with the (re)discovery of highly efficient coupling chemistries that allow quantitative, chemoselective, and orthogonal functionalization of reactive polymer precursors. After some basic mechanistic considerations, this Highlight will provide an overview of the development and evolution of eight main classes of post-polymerization modification reactions. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013

Amphiphilic diblock copolymers have the ability to adapt their surface's molecular composition to the hydrophilicity of their environment. In the case of about equal volume fractions of the two polymer blocks, the bulk of these polymers is known to develop a laminar ordering. We report here our investigation of the relationship between bulk ordering and surface morphology/chemical composition in thin films of such an amphiphilic diblock copolymer. Upon annealing in vacuum, the expected lamella ordering in the bulk of the film is observed and we find the morphology of the film surface to be defined by the thickness of the as-deposited film: If the as-deposited thickness matches the height of a lamella stack, then the film exhibits a smooth surface. Otherwise, an incomplete lamella forms at the film surface. We show that the coverage of this incomplete layer can be quantified by X-ray reflectivity. To establish the lamella ordering in the bulk, the film needs to be annealed above the glass temperature of the two blocks. Molecular segregation at the film surface, however, is already occurring at temperatures well below the glass temperature of the two blocks. This indicates that below the glass temperature of the blocks the bulk of the thin film is “frozen,” whereas the polymer chains composing the surface lamella have an increased mobility. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys., 2013, 51, 1282–1287

The successful sequence-controlled installation of an activated ester using a newly designed monomer pentafluorophenyl 4-maleimidobenzoate is demonstrated. Pentafluorophenyl 4-maleimidobenzoate is kinetically installed at different stages of a nitroxide-mediated polymerization, namely, near the α-chain end and in the middle of a PS chain. In addition, successful installation of apolar and polar functional groups is achieved via post-polymerization functionalization, which demonstrated the versatility of the synthesis of a universal precursor for locally functionalized polymers.

A strategy to fabricate nanostructured poly(3-hexylthiophene) (P3HT) films for organic photovoltaic (OPV) cells by a direct transfer method from a reusable soft replica mold is presented. The flexible polyfluoropolyether (PFPE) replica mold allows low-pressure and low- temperature process condition for the successful transfer of nanostructured P3HT films onto PEDOT/PSS-coated ITO substrates. To reduce the fabrication cost of masters in large area, we employed well-ordered anodic aluminum oxide (AAO) as a template. Also, we provide a method to fabricate reversed nanostructures by exploiting the self-replication of replica molds. The concept of the transfer method in low temperature with a flexible and reusable replica mold obtained from an AAO template will be a firm foundation for a low-cost fabrication process of ordered OPVs.

Uniform benzophenone-covered AuNP (Bph-AuNP) were prepared in a two-phase ethyl acetate/water reduction of auric acid employing a benzophenone-functionalized disulfide. Upon UV irradiation, the benzophenone carbonyl bond was excited allowing for insertion into a nearby C–H bond and thus a covalent attachment of the AuNP onto a substrate exhibiting C–H bonds. Using this technique, polycarbonate–gold core–shell particles were easily obtained, providing a simple synthetic pathway toward AuNP hybrids with polycondensation polymers. Bph-AuNP were also covalently attached to alkylated silica microspheres or cellulose paper. UV irradiation through a photo mask enabled a photolithographic surface patterning.

We present the synthesis of reactive polymer brushes prepared by surface reversible addition–fragmentation chain transfer polymerization of pentafluorophenyl acrylate. The reactive ester moieties can be used to functionalize the polymer brush film with virtually any functionality by simple post-polymerization modification with amines. Dithiobenzoic acid benzyl-(4-ethyltrimethoxylsilyl) ester was used as the surface chain transfer agent (S-CTA) and the anchoring group onto the silicon substrates. Reactive polymer brushes with adjustable molecular weight, high grafting density, and conformal coverage through the grafting-from approach were obtained. Subsequently, the reactive polymer brushes were converted with amino-spiropyrans resulting in reversible light-responsive polymer brush films. The wetting behavior could be altered by irradiation with ultraviolet (UV) or visible light. Furthermore, a patterned surface of polymer brushes was obtained using a lithography technique. UV irradiation of the S-CTA-modified substrates leads to a selective degradation of S-CTA in the exposed areas and gives patterned activated polymer brushes after a subsequent RAFT polymerization step. Conversion of the patterned polymer brushes with 5-((2-aminoethyl)amino)naphthalene-1-sulfonic acid resulted in patterned fluorescent polymer brush films. The utilization of reactive polymer brushes offers an easy approach in the fabrication of highly functional brushes, even for functionalities whose introduction is limited by other strategies. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012