Gel Formation Processes and Materials for Functional Thin Films

Dear Colleagues,

This Special Issue on “Gel Formation Processes and Materials for Functional Thin Films” is dedicated to the gels applied for obtaining thin films, which have a variety of applications.

Gels are multi-component soft materials with long mechanical relaxation times that can be deformed with modest stresses. One of the main characteristics of gels is their ability to hold shape. Gelation is the transition of a liquid to a disordered solid via the formation of a network of chemical or physical bonds between the molecules or particles composing the liquid.

Gels are commonly used for a great deal of applications: sustained-release delivery systems, materials responsive to specific molecules (glucose or antigens used as biosensors), diapers, contact lenses, medical electrodes, water–gel explosives, breast implants, paints, coatings, adhesives, recyclable absorbents, bioreactors containing immobilized enzymes, bioassay systems, display devices, actuators, valves, sensors, artificial muscles for robotic devices, chemical memories, optical shutters, molecular separation systems and toys.

Sol–gel processing is a versatile technique that may be employed to create a wide range of materials based on biopolymers, such as glasses, ceramics, and coatings. It is considered an economical and straightforward method. Chemical tailoring of raw materials to produce new functional compositions is more feasible than conventional methods. The sol–gel process entails the chemical transformation of a sol (liquid) into a gel (solid). A polymer solution is formed into a thin film on a substrate using different methods, such dip coating, spin coating, or spray coating. After drying and heating, the coated substrate removes the solvent and promotes crosslinking of the polymer molecules; then, a solid film is formed. By changing the composition of the starting materials and processing conditions, the characteristics of the resulting materials based on polymers can be tailored.

Thin-film coatings have been explored extensively since films are well suited for studying the physical properties of materials and have many scientific, technological, and commercial applications. Among the numerous applications is optical coating, as films are known for their distinctive optical properties that can be applied in electronic devices, data communications, ultra-fast optical data storage, sensor materials, etc. Moreover, films are used as protect coatings with good thermal and electrical properties and high resistance to oxidation. Porous films are used in various fields because of their high surface area. They are used in solar cells and in many surface reactions as catalysis, sensors, and so on.

Since it is impossible to cover all aspects of gel formation processes, we are hoping that this Special Issue will stimulate new research and discoveries in this field.

Dr. Denitsa K. Elenkova
Dr. Katerina Lazarova
Dr. Joana Zaharieva
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Gels is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2100 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

• sol–gel method
• gels
• thin films
• deep coating
• spin coating
• film applications
• membranes