Photolabile Carboxylic Acid Protected Terpolymers for Surface Patterning. Part 1:  Polymer Synthesis and Film Characterization

Abstract

We present the synthesis and characterization of a series of photolabile phenacyl derivative polymers and their subsequent thin film preparation. These systems are composed of up to three methacrylate units: a photolabile component including a p-methoxyphenacyl moiety which after selective irradiation (UV/laser) can provide free carboxylic groups in specific areas for further modification; an anchoring unit, trimethoxysiloxane or glycidyl methacrylate derivative, which allows the covalent attachment of the polymer to the substrate; and a spacer, methyl methacrylate or styrene, which in the appropriate proportion ensures the formation of films with good quality. Structural and thermal properties of these materials have been analyzed by means of NMR, FTIR, elemental analysis, UV, gel permeation chromatography, differental scanning calorimetry, and thermogravimetric analysis. The polymers have been subsequently processed by spin coating to render ultrathin films (<50 nm). Topographic and structural characterization studies of the films have been carried out with atomic force microscopy, contact angle measurements, and X-ray photoelectron spectroscopy. The extent of the substrate attachment of the polymers depending on the nature of the anchoring groups have been studied by ellipsometry and FTIR.

Synthesis of diblock copolymers bearing p-methoxyphenacyl side groups

“…The monomer was synthesized following the procedure described by Voit et al 23 para-Methoxyphenacyl methacrylate is obtained by a nucleophilic substitution which consists in firstly deprotonating the carboxylic acid with triethylamine to generate the carboxylate which substitutes the bromide of 2-bromo-4 0methoxyacetophenone in a second step (Scheme 1).…”

“…Indeed, FRP was largely used for the synthesis of homopolymers and statistical copolymers. [21][22][23][24] The grafting of an acetophenone derivative onto poly(methacrylic acid) by a nucleophilic substitution has been used for the formation of statistical copolymers bearing phenacyl derivatives as side groups. 26 Only one example of polymerization by a CRP technique has been reported up to now: phenacyl methacrylate was polymerized by atom transfer radical polymerization (ATRP) to produce homopolymers and statistical copolymers.…”

Malonic Acid Diazoesters for C−H Insertion Crosslinking (CHic) Reactions: A Versatile Method for the Generation of Tailor‐Made Surfaces

“…Tunable film thickness of the coating and the presence of a high surface density of functional groups, combined with excellent mechanical and chemical stability, are important features of such modified surfaces. The versatility of such surface architectures renders them very attractive for a broad range of applications ranging from biomedicine to microsystems engineering …”

Malonic Acid Diazoesters for C−H Insertion Crosslinking (CHic) Reactions: A Versatile Method for the Generation of Tailor‐Made Surfaces

“…[1][2][3][4][5][6] Crosslinking of bulk polymers is ac ommon method to stabilize the shape and internal structure of polymer objects and, therefore,many methods have been reported on how to achieve well-defined polymer networks. Tu nable film thickness of the coating and the presence of ah igh surface density of functional groups,c ombined with excellent mechanical and chemical stability,a re important features of such modified surfaces.T he versatility of such surface architectures renders them very attractive for abroad range of applications ranging from biomedicine to microsystems engineering.…”

“…Tu nable film thickness of the coating and the presence of ah igh surface density of functional groups,c ombined with excellent mechanical and chemical stability,a re important features of such modified surfaces.T he versatility of such surface architectures renders them very attractive for abroad range of applications ranging from biomedicine to microsystems engineering. [1][2][3][4][5][6] Crosslinking of bulk polymers is ac ommon method to stabilize the shape and internal structure of polymer objects and, therefore,many methods have been reported on how to achieve well-defined polymer networks. [7][8][9][10][11][12] To obtain crosslinked systems,t wo strategies can be followed:c rosslinking polymerization or the transformation of preformed polymers into polymer networks.H owever,i ts hould be noted, that most methods developed for the formation of bulk networks cannot be easily transferred to the generation of thin films on arbitrarily shaped (i.e.n on-planar) surfaces.P rocesses that involve viscous layers (solutions or melts) might deform during the process owing to these layers having the ability to flow.Systems with added crosslinkers can have atendencyfor phase separation, which is very detrimental for the generation of homogeneous thin films.Furthermore,the performance of chemical reactions in glassy thin films is expected to be rather difficult because of slow kinetics.…”