Langmuir−Blodgett Films of a Novel Cellulose Derivative with Dihydrophytyl Group:  The Ability to Anchor β-Carotene Molecules

Abstract

A novel cellulose derivative, 6-O-dihydrophytylcellulose (DHPC), was first synthesized via a ring-opening polymerization and allowed to self-assemble onto an air-water interface. Langmuir-Blodgett (LB) films were characterized with atomic force microscope (AFM), UV-vis spectroscopy, and Fourier transform infrared spectroscopy. The surface pressure-area (pi-A) isotherms for DHPC and beta-carotene (betaC) mixture indicated strong interaction between these compounds to pack well. Thus, DHPC has the ability to anchor betaC in the monolayer. It was proved that a betaC-DHPC monolayer was transferred successfully onto a substrate, yielding Y-type LB films by UV spectroscopic analysis. The transmission and reflection-absorption IR spectra (RAS) indicated that the dihydrophytyl chains had almost trans-zigzag conformation and were oriented nearly perpendicular to the substrate. AFM section analysis revealed the thickness per layer to be 2.32 nm. Consequently, DHPC was found to be an appropriate matrix to fabricate the mixed LB films containing betaC.

First Cellulose Langmuir‐Blodgett Films towards Photocurrent Generation Systems

“…[11][12][13][14] In addition, the LB films of highly regioselectively substituted cellulose derivatives with a controlled pattern of functionalization and with well defined supramolecular nanoscale architecture, based on the basic concept of the role-sharing functionalization of cellulose, have bright prospects in the development of molecular assemblies with highly efficient photo-energy conversion. [15,16] We report herein the fabrication of LB films consisting (Figure 1). …”

“…0.55-0.6 nm 2 and 2-2.5 nm 2 , respectively. [9,16] Therefore, the limiting area of 1 suggests that the porphyrin rings are oriented almost perpendicular to the water surface. A monolayer could be successfully deposited onto several substrates at a surface pressure of 10 mN Á m…”

Fabrication of anodic photocurrent generation systems by use of 6-O-dihydrophytylcellulose as a matrix or a scaffold of porphyrins

“…The limiting molecular areas, which are obtained by extrapolating the linear region of the isotherm to zero surface pressure, decrease with increasing the DPor proportion in the mixture and exhibit a close linear relationship with the proportion (Table 1). This observation suggests that any remarkable attractive interaction between DPor and DHPC did not occur in sharp contrast to the strong interaction of DHPC with b-carotene (Sakakibara et al 2006). In the DPor-DHPC mixing ratios of 1:9, 2:8, and 5:5, the isotherms consist of two steep rises in pressure and a gradual transition phase between two regions, suggesting the weak immiscibility of the mixed films (Petty 1996).…”

“…Materials 6-O-Dihydrophytylcellulose was prepared by ringopening polymerization of the glucose orthopivalate derivative as described previously (Sakakibara et al 2006); M n = 2.2 9 10 4 ; DP n = 35.9. 5-(4 0 -Carboxyphenyl)-10,15,20-triphenylporphin (TPP-COOH) was prepared according to the literature procedures (Matile et al 1996;Tomé et al 2005).…”

“…1) as a matrix or as a scaffold of porphyrins toward anodic photocurrent generation systems. DHPC is an appropriate matrix to prepare the mixed LB films of several molecules with a diterpenoid carbon skeleton, such as b-carotene or dihydrophytyl ferrocenoate (Sakakibara et al 2006(Sakakibara et al , 2007a. Two fabrication methods were considered: (1) mixing a low-molecular-weight porphyrin having a diterpenoid carbon skeleton with DHPC as a matrix (matrix fabrication) and (2) introducing porphyrin molecules to the secondary hydroxyl groups of DHPC as a scaffold via a covalent bond (scaffold fabrication).…”