## 1 Introduction  
Stimuli-responsive polymers show their potential in the variations of properties upon the application of an external stimuli [1]. Their peculiarities have attracted increasing interest in recent decades for their potential applications as smart materials, e.g., in drug delivery [2], tissue engineering [3], biosensing [4], and smart coating [5]. Among various possible stimuli, temperature is the most commonly exploited due to the ease of applying the stimulus, the possible applications in biological systems, and the often reversible nature of the change in properties of the polymer [6]. Thermoresponsive polymers can phase separately from a solution when temperature is increased or decreased, resulting in a miscibility gap in the phase diagram. If raising the temperature causes the immiscibility,the mixture exhibits lower critical solution temperature (LCST) behavior, whereas if the opposite is true, it exhibits upper critical solution temperature (UCST). The critical solution temperatures are considered the point of the minimum or maximum of the coexistence curve on the phase diagram, whereas the temperature at which a solution of a given concentration undergoes phase separation is called the cloud point temperature (\(T_{\text{cp}}\)). Systems possessing LCST are the most extensively studied of the two classes [7]. Thermodynamically, the separation between the two phases is caused by a negative entropy of mixing between the polymer and the solvent, an element increasing in importance with temperature. This counteracts the favorable exothermic enthalpy contribution that is due to the formation of hydrogen bonds between the hydrophilic components of the polymer and the surrounding water molecules [8; 9]. When the temperature at which the entropic term prevails is reached, the hydrated conformation, present at low temperatures, changes to a contracted conformation, minimizing contact with water, and the contracted polymer coils start aggregating into larger structures. LCST-thermoresponsive polymers are commonly described as subject to a coil-to-globule transition. This describes the conformational changes that a dissolved polymeric chain in an unfolded random coil conformation undergoes when reaching cloud point temperature, a contraction of the structure into a compact globule, which is accompanied by an aggregation of polymers due to hydrophobic interactions becoming dominant upon the loss of bound water [10; 11]. However, LCST-like phase separation is also a feature of other kinds of systems where polymer chains are not dissolved into a random coil conformation, but rather are dispersed into small globular structures even below the cloud point. Such globular particles may be constituted by a number of macromolecules self-assembling into micellar structures [12; 13] or by a single polymeric chain self-folding into a compact nanoparticle, commonly termed a unimer micelle [14; 15; 16], which is generated by intra-macromolecular hydrophobic interactions. The most common way to measure the cloud point for a thermoresponsive polymer is through turbidimetry measurements [17], thanks to the formation of a heterogeneous milky dispersion above this temperature. Dynamic light scattering (DLS) is also employed to study the size of polymer aggregation below and above the phase transition, as well as to detect such a transition. Differential scanning calorimetry (DSC) is another promising technique useful to study the transition by looking at the heat exchanged during a thermal scan. Despite its potential, the calorimetric evaluation of the phase transition is not so common in the literature. Extensive calorimetric investigations have been reported for the class of poly(\(N\)-isopropylacrylamide) PNIPAM, one of the most studied systems among thermoresponsive polymers [18; 19; 20; 21; 22; 23]. In particular, the studies in the field report a coil-to-globule transition caused by dehydration of the polymer chains during the heating scan followed by their aggregation into concentrated solutions.