Dear Colleagues,

Janus particles, named after the ancient Roman god Janus who has two faces on his head, were used to describe a unique class of colloidal particles with more than a single type of surface chemistry, composition, or physical functionalities, ranging in size from hundreds of nanometers to a few micrometers. The idea of Janus particles was first popularized by Pierre-Gilles de Gennes in his 1991 Nobel Prize lecture. It did not attract much notice until around 15 years later, but, since then, interest in the topic has grown more and more every year. Because of their asymmetry, Janus particles can self-assemble into complex materials and structures that are not attainable for their homogeneous counterparts. Their intriguing and practical features of multidirectional interaction open up new avenues for research in the realms of soft matter, fundamental materials, as well as applications in other fields and technologies, such as solid surfactants, interfacial catalyst, electronic paper, microprobes, micromotors, and other building blocks for functional materials.

Technological advances in manufacturing novel particles would dramatically improve our ability to build sustainable infrastructure, develop personalized medicine, elevate cost efficiency, and reduce energy consumption. One critical factor in determining the product properties is the particle morphology. It has been a longstanding goal to create novel particle morphologies that can help to improve the coating formulation and impart new functionalities. One promising example is the Janus morphology. They can serve as a better stabilizer for emulsions, offer new drug delivery capabilities, and create a multi-functional coating matrix. However, the ability to create and control particle morphologies in large-scale manufacture remains extremely limited. Meanwhile, with the fast-expanding study of functional Janus particles, it becomes urgent to explore more industrial-related applications for these intriguing materials.

We invite contributions on the synthesis of the Janus particles (block polymer self-assembly, direct seeded growth, surface selective modification, emulsion-based phase separation, etc.). While contributions reporting their properties (emulsification, self-assembly, environmental responsiveness, etc.) and potential applications are highly encouraged, studies reporting Janus particles because of their intriguing morphologies are also welcome. We particularly encourage practical application studies utilizing Janus particles, such as smart coating additives, targeted delivery, and building blocks for hierarchical structures.

Dr. Yifan Li
Dr. Xiaoshuang Wei
Dr. Shensheng Chen
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. Crystals 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 2600 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.

• janus particles
• emulsion polymerization
• microfluidic synthesis
• amphiphilicity
• catalysis
• dipolar
• nanoparticles
• asymmetric properties
• multicompartment particles
• microprobes, reconfigurable materials and micromotors
• solid surfactants
• block copolymers
• surface modification and compartmentalization
• smart materials
• multifunctional coatings
• active surfaces and interfaces
• coating additives