Preparation of Compositional Gradient Polymeric Films Based on Gradient Mesh Template

Abstract

In this paper, a template-filling method was found to prepare composition gradient gelatin films by incorporating α-[3-(2,3-epoxypropoxy) propyl]-ω-butyl-polydimethylsiloxane (PDMS–E) grafted gelatin (PGG) into a gradient gelatin mesh template. The method can be used to prepare other composition gradient biopolymer films. Gradient mesh template prepared by the methacrylic anhydride cross-linked gelatin under temperature gradient field. The porosity of the template decreased from 89 to 35% which was accompanied by decrease in average pore size from 160 to 50 µm. Colloidal particles about 0.9~10 µm were formed from PGG after adding them to a mixed solvent system of 9:1 ( v / v ) of ethanol/water, which were filled in the mesh template under vacuum (0.06 MPa). A gradient film was obtained after drying at room temperature for 48 h. The results of scanning electron microscope-energy dispersive X-ray combined with freezing microtome and Fourier transform infrared spectroscopy suggested that the distribution of the Si element along the thickness showed a typical gradient pattern, which led to hydrophilic/hydrophobic continuous changing along the thickness of film. The water vapor permeability, thermal gravimetric analysis, differential scanning calorimetry and dynamic mechanical tensile results show that the gradient films had excellent water vapor permeability and flexibility, and hence could be used as biomimetic materials and leather finishing agents.

Electric field‐driven preparation of elastomer/plastic nanoparticles gradient films with enhanced damping property

“…By taking advantages of gradient change in properties such as modulus and hydrophibility of the PGMs, one of the applications of PGMs is joining two materials of different stiffness to avoid stress concentrations in the contact zone. For example, in the aerospace and electronics and electric application, the polymer material often was adhered between the substrates of a different hardness and temperature . When the device suffers the constant vibration or temperature shock, mismatch of modulus or coefficient of thermal expansion between the substrate and polymer will cause breakage at interface .…”

Gradient structure polyimide/graphene composite aerogels fabricated by layer‐by‐layer assembly and unidirectional freezing

“…pore size or density shows gradient change along one direction of the materials, [5][6][7] exhibit unique advantages in aerospace, medical science, environmental protection, and other fields. [8][9][10][11][12] Suk et al 13 prepared gradient porous Ti material by pulse current sintering process.…”