Tuning and Transcription of the Supramolecular Organization of a Fluorescent Silsesquioxane Precursor into Silica‐Based Materials through Direct Photochemical Hydrolysis–Polycondensation and Micropatterning

Abstract

A new fluorescent silsequioxane precursor with tuned optical properties and controlled aggregation properties is designed. The two cyclohexyl moieties introduced in the molecular structure allow the formation of very good quality films. The J‐aggregated structure is transcribed into the solid by photoacid‐catalyzed hydrolysis–polycondensation. Aggregation of the chromophores is reduced and highly fluorescent materials are obtained. The photoacid generator lies on the surface of the homogeneous layer of the sol–gel precursor. This phase separation presents several advantages, including UV protection of the chromophore and easy removal of the PAG. The first example of chemical amplification in the photolithography of the conjugated silsesquioxane precursor is demonstrated. As hydrolysis–polycondensation could be achieved in a controlled way by UV exposure, chemically amplified photolithography is achieved by irradiating a composite film (∼110 nm thick) on silicon wafer by using a copper TEM grid as shadow mask. The pattern is produced uniformly on a miscroscopic scale of 3 mm, the photopatterned pixels remaining highly fluorescent. The sizes of the photolithographed pixels correspond to the sizes of the rectangular holes of the 300 × 75 mesh grid (hole: 63 <$>μ<$>m × 204 <$>μ<$>m).

Mimicking nature: Self-strengthening properties in a dental adhesive

“…Since the pioneering work of Crivello, onium salts have been widely used as photoinitiators to generate photoacids and initiate the cationic photopolymerization [32]. The photoacid-induced sol-gel reaction has been used in a few studies to prepare nanocomposite films [32–37]. Under acidic conditions, it is likely that an alkoxide group is protonated in a rapid first step, and then the hydrolysis occurs.…”

Activation of the sol–gel process by visible light-emitting diodes (LEDs) for the synthesis of inorganic films

“…[1][2][3][4] In typical experiments, bulk films based on alkoxysilane precursors have been directly hydrolyzed and condensed through the catalytic action of Brönsted acids released upon UV-C (280-200 nm) and UV-B (280-315 nm) irradiation. [1][2][3][4] In typical experiments, bulk films based on alkoxysilane precursors have been directly hydrolyzed and condensed through the catalytic action of Brönsted acids released upon UV-C (280-200 nm) and UV-B (280-315 nm) irradiation.…”

Photoinduced self-assembly of carboxylic acid-terminated lamellar silsesquioxane: highly functional films for attaching and patterning amino-based ligands

“…1,2 In the early development phase, the reported hybrids were amorphous, and their growth was essentially driven by the inexhaustible choice of organic moieties achieved through the Si-C bond molecular scale homogeneity. 8 In fact, unique chemical or physical properties may emerge from hybrid materials when organic moieties form mesoscopically segregated functional domains, both ordered and conned. 3,4 Harnessing silsesquioxanes in a way that the organic and siloxane fragments self-assemble into spatially dened and organized nanodomains has been a very attractive goal to fabricate a wide spectrum of advanced hybrid nanomaterials including membranes, 5 conductive lms, 6 absorbents 7 and optoelectronic devices.…”