Facile Preparation of Highly Oriented Poly(vinylidene fluoride) Langmuir–Blodgett Nanofilms Assisted by Amphiphilic Polymer Nanosheets

Abstract

We describe a facile and novel method for preparing highly dense Langmuir–Blodgett (LB) nanofilms of poly(vinylidene fluoride) (PVDF) with precisely adjustable film thickness from several to hundreds of nanometers, assisted by amphiphilic poly(N-dodecylacrylamide) (pDDA) nanosheets. Even at a molar mixing ratio of PVDF:pDDA up to 50:1, the high collapse surface pressure of 44.4 mN/m obtained using this method is a breakthrough for the preparation of PVDF LB nanofilms, which is devoted to the resulting high-density PVDF nanofilms. As shown by FTIR and XRD measurements, the mixed LB nanofilms without any postprocessing comprised dominant ferroelectric β phase of ∼95% and negligible paraelectric α phase. Furthermore, through control of the surface pressure, controllable PVDF crystal morphologies were achieved. Moreover, β phase PVDF dominates in all cases. After applying a dc bias of 5 V through a conductive cantilever, the local polarized pattern on the surface of a nine-layer mixed LB nanofilm observed using Kelvin probe force microscopy indicates that it is possible to induce all dipoles in one direction in the mixed LB nanofilm, which is promising for application in low-voltage nanoelectronics.

Facile preparation of highly oriented poly(vinylidene fluoride) uniform films and their ferro- and piezoelectric properties

“…29,30 Recently, the Langmuir-Blodgett (LB) technique was used to obtain PVDF nanolms containing the bphase content up to 95%. 31,32 It was claimed that hydrogen bonding between PVDF and water contributes to the formation of b-phase and the dipole orientation. However, production of oriented PVDF lms with high content of b-phase without using external agent and sophisticated process is a challenging.…”

Preparation and Device Applications of Ferroelectric β-PVDF Films

“…Zhu et al reported that the 5-35 layers PVDF nanofilms could be prepared by the LB method at 20°C [30]. The dependence of root-mean square (RMS) surface roughness on the thickness of PVDF nanofilms is shown in Figure 4.…”

Luminescence Properties of Platinum Porphyrin Embedded in Multilayered Polymer Nanosheets

“…The monolayer is easily transferable on solid supports as Y-type LB films over 700 layers. [2] A diverse range of molecules have been successfully incorporated in ultrathin polymer films at the monolayer level: e.g., organometallic complexes, [3] aromatic hydrocarbons, [4][5][6] redox active groups, [7,8] thermosensitive groups, [9] nonlinear optical active groups, [10][11][12] ferroelectric polymers, [13] and polyhedral oligomeric silsesquioxane. [14,15] The ultrathin polymer films act as a nanoruler manipulating nanomaterials systematically with nanoscale precision.…”