Nanotechnology-enabled materials and devices will play a major role in sectors such as electronics, communications, construction, and energy; all of which are key areas for the implementation of smart cities.

This is a quote from an article by Michael Berger published on the Nanowerk website. Further materials of this article are taken from this above-mentioned article and seem to me very important.

A smart city is an infrastructure framework that addresses the growing urbanization challenges by embracing integrated and automated information and communication technologies to help optimize all city operations, help achieve sustainability goals and better quality of life for its citizens. The development of smart cities requires more efficient and less polluting transport systems, more habitable residential buildings that require less energy to operate, establishment of better

managed public services of all kinds (gas, water, electricity, waste disposal, etc.).

When it comes to nanotechnology and the development of new nanomaterials and nano devices that   smart cities can benefit from, there are several areas that immediately stand out:

Millimeter- wave technology for 5G networks for virtual city-wide networks

Nanomaterials to be used in the construction of smart buildings

Tiny sensors or even smart dust to enable city-wide IoT

Smart windows to regulate buildings' indoor climate

Efficient, smart lighting systems

Energy-generating smart roads

High storage capacity batteries and ultracapacitors with fast loading times for electric vehicles and battery storage of renewable energy.

Water purification and filtration.

Let's take a look at some of the major nanotechnologies at play:

 5G Networks                                                                                          

By providing higher data rates, increased traffic capacity, ultra-low latency, and high connection density, 5G offers opportunities for urban innovators striving to create smart city services.

In conjunction with the Internet of Things (IoT) and crowd management tools, 5G should enable transport operators to improve their response to overcrowding and deliver information to passengers on safer routes and vehicles.

Researchers have demonstrated how properties of graphene enable ultra-wide bandwidth communications coupled with low power consumption to radically change the way data is transmitted across the optical communications systems. This could make graphene-integrated devices the key ingredient in the evolution of 5G and the IoT.

Already, researchers have demonstrated wafer-scale production of graphene-based photonic devices, enabling automation and paving the way to large scale production.

There are already plans to use the sub-terahertz range as a working range in the sixth generation (6G) wireless technology, which is being prepared for active introduction in our lives from the early 2030s. Researchers have already developed magnetic nanopowders to be used in 6G reception devices.

Nanotechnology-enabled sensor technology

Data-collecting sensors embedded in all kinds of devices are at the core of IoT applications. Especially in demand are light-weight, thin, robust, and flexible sensors that can be seamlessly integrated onto any surface, which is difficult to realize in conventional electromechanical sensors.

Wireless sensors, whether electronic or photonic (light-based), can monitor such environmental factors as humidity, temperature and air pressure. One example of IoT-suitable sensing devices are fully integrated and packaged wireless sensors for environmental           monitoring applications that can be 3S printed.

Another example are graphene sensors embedded into RFIDs for wireless humidity sensing: By layering graphene oxide (a derivative of graphene) over graphene to create a flexible heterostructure the team have developed humidity sensors for remote sensing with the ability to connect to any wireless network.

Still a bit in the future is smart dust – imagine a cloud of sensors, each the size of a grain of sand or even smaller, blown aloft by hurricane winds and relaying data on the storm to weather stations below. Picture an invisible sensor network embedded into a smart city’s roads to monitor traffic, road surface damage and identify available parking spaces – all in real time. Or billions of nanosensors distributed over areas with fire hazards to detect a fire at its very beginning. Or envision programmable smart dust that triggers an alarm signal when invisible microcracks are detected in a turbine blade.

Nanomaterials to be used in building construction

Nanotechnology has a significant impact in the construction sector. Several applications have been developed for this specific sector to improve the durability and enhanced performance of construction

components, energy efficiency and safety of the buildings, facilitating the ease of maintenance and to provide increased living comfort.

Nanoparticles of TiO2, Al2O3 or ZnO are applied as a final coating on construction ceramics to bring this characteristic to the surfaces. TiO2 is being used for its ability to break down dirt or pollution when exposed to UV light and then allow it to be washed off by rainwater on surfaces like tiles, glass and sanitary ware. ZnO is used to have UV resistance in both coatings and paints. Nanosized Al2O3 particles are used to make surfaces scratch resistant. These surfaces also prevent / decelerate formation of bad smells, fungus and mould.

Basic construction materials cement, concrete and steel will also benefit from nanotechnology. Addition of nanoparticles will lead to stronger, more durable, self-healing, air purifying, fire resistant, easy to clean and quick compacting concrete. Some of the nanoparticles that could be used for these features are nano silica (silica fume), nanostructured metals, carbon nanotubes (CNTs) and carbon nanofibers (CNFs).

A bit more futuristic: With the addition of engineered nanomaterials that change the crystalline structure of concrete, imaginative architectural designs become  possible and buildings achieve new heights and forms. Steel reinforcements are a thing of the past as concrete structures have ample strength to support themselves, in shapes that make the Guggenheim Museum look tame. Engineered from the strongest, lightest nanomaterials, suspension bridges and other weight-bearing elements look more like spider webs than structures.

Already, researchers have demonstrated strengthening of concrete by infusing it with nanocrystals or by nanoengineering concrete with graphene, resulting in a new composite material that is more than

twice as strong and four times more water resistant than existing concretes.

Widespread use of engineered nanomaterials in the Smart City

Engineered nanomaterials are expected to be widely used in city environments. Carbon dioxide and other air pollutants are reduced as power plants, buildings, and vehicles use nanostructured membranes. Recycled water is purified with nano-enabled filtration and osmosis systems, for instance by using nanofiltration membranes to treat industrial wastewater from heavy metals, and these systems are available for individual households and new local urban water treatment systems.

Nanowerk, 2021