A glucose-sensitive inverse opal hydrogel was synthesized through photopolymerization of 2-hydroxyethyl methacrylate and 3-acrylamidophenylboronic acid within the interstitial space of a dried poly(styrene) colloidal crystal template, followed by template removal. Charged complex formation between the phenylboronic acid functional group and the 1,2-cis-diol glucose resulted in reversible swelling of the inverse opal hydrogel, which was observed through shifts in the optical diffraction wavelength. The hydrogel was sensitive to glucose at physiological concentrations and ionic strength. The effects of phenylboronic acid concentration, ionic strength, and buffer pH on the equilibrium hydrogel swelling were also studied. The kinetics of hydrogel swelling was also examined, and it was found that the rate of diffraction shift matched well with diffusion-limited kinetics. Additionally, the diffraction response was compared with simulations using the scalar wave approximation and transfer matrix method.

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The wetting behavior of P(S-b-I) and P(S-b-nBMA) thin films placed upon tunable P(S-r-MMA) brush surfaces is addressed. Homopolymer dewetting experiments show an increase in interfacial energy between PI and P(S-r-MMA) with increasing styrene fraction, while the interfacial energy dependence of PnBMA with brush composition was indeterminate. Reflection optical micrographs of block copolymer films cast on PS and PMMA brush surfaces show island/hole structures that are indicative of a parallel orientation of the block copolymer domains with respect to the film boundaries. The micrographs are identical in structure and are comprised of the same interference colors, indicating antisymmetric wetting conditions for films cast upon both PS and PMMA brush surfaces. Thus, for P(S-b-I) and P(S-b-nBMA) films cast upon PMMA brush surfaces, unfavorable wetting of the PS component occurs at the PMMA brush surface in order to avert PI/PMMA and PnBMA/PMMA interactions which are more unfavorable. Consequently, the dependence of the interfacial energy between PI or PnBMA with P(S-r-MMA) random copolymer brushes as a function of styrene content does not influence the behavior of these systems. The general wetting behavior of block copolymer films on random copolymer surfaces is discussed with specific attention being made to wetting condition inversions and neutral surfaces.

The fabrication and characterization of two‐photon polymerized features written within and outside of colloidal crystals is presented. Two‐photon polymerization (TPP) response diagrams are introduced and developed to map the polymerization and damage thresholds for features written via modulated beam rastering. The use of tris[4‐(7‐benzothiazol‐2‐yl‐9,9‐diethylfluoren‐2‐yl)phenyl]amine (AF‐350) as an initiator for TPP is demonstrated for the first time and TPP response diagrams illustrate the polymerization window. These diagrams also demonstrate that the polymerization behavior within and outside of colloidal crystals is similar and electron microscopy reveals nearly identical resolution. Fluorescence confocal microscopy further enables visualization of non‐self‐supporting, three‐dimensional TPP features within self‐assembled photonic crystals. Finally, microspot spectroscopy is collected from a two‐photon feature written within a colloidal crystal and this is compared with simulation.

We present a quantitative experimental and theoretical study of the effect of numerical aperture (NA) on the Bragg diffraction from a dry polystyrene colloidal crystal. The diffraction peak parameters changed noticeably as the NA was increased from 0.017 to 0.5. The diffraction wavelength blueshifted 1.4% from 584 to 576 nm, and the normalized full width at half-maximum increased from 6.2% to 7.0%. These shifts occurred primarily for NA > 0.3 and agreed qualitatively with results predicted by a layered Korringa-Kohn-Rostoker method. Thus, by using focusing optics with NAs below 0.3, the diffraction response of low-photonic-strength mesostructures may be compared with normal-incidence experimental and theoretical data.